Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1532634 > unrolled thread
| Started by | Scott Bauer <scott.bauer@intel.com> |
|---|---|
| First post | 2016-11-29 19:30 +0100 |
| Last post | 2016-12-08 01:20 +0100 |
| Articles | 20 on this page of 27 — 7 participants |
Back to article view | Back to linux.kernel
BUG: KASAN: stack-out-of-bounds in unwind_get_return_address Scott Bauer <scott.bauer@intel.com> - 2016-11-29 19:30 +0100
Re: BUG: KASAN: stack-out-of-bounds in unwind_get_return_address Josh Poimboeuf <jpoimboe@redhat.com> - 2016-11-30 19:40 +0100
Re: BUG: KASAN: stack-out-of-bounds in unwind_get_return_address Scott Bauer <scott.bauer@intel.com> - 2016-11-30 20:10 +0100
[PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume Josh Poimboeuf <jpoimboe@redhat.com> - 2016-12-01 00:20 +0100
Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume "Rafael J. Wysocki" <rafael@kernel.org> - 2016-12-01 15:10 +0100
Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume Josh Poimboeuf <jpoimboe@redhat.com> - 2016-12-01 18:00 +0100
Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume "Rafael J. Wysocki" <rafael@kernel.org> - 2016-12-01 18:10 +0100
Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume Ingo Molnar <mingo@kernel.org> - 2016-12-02 11:20 +0100
Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume Josh Poimboeuf <jpoimboe@redhat.com> - 2016-12-01 16:00 +0100
Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume Josh Poimboeuf <jpoimboe@redhat.com> - 2016-12-01 17:50 +0100
Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume Dmitry Vyukov <dvyukov@google.com> - 2016-12-01 18:00 +0100
Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume Josh Poimboeuf <jpoimboe@redhat.com> - 2016-12-01 18:20 +0100
Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume Dmitry Vyukov <dvyukov@google.com> - 2016-12-01 18:30 +0100
Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume Josh Poimboeuf <jpoimboe@redhat.com> - 2016-12-01 18:40 +0100
Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume Dmitry Vyukov <dvyukov@google.com> - 2016-12-01 18:50 +0100
Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume Josh Poimboeuf <jpoimboe@redhat.com> - 2016-12-01 19:00 +0100
[PATCH v2] x86/suspend: fix false positive KASAN warning on suspend/resume Josh Poimboeuf <jpoimboe@redhat.com> - 2016-12-01 21:40 +0100
Re: [PATCH v2] x86/suspend: fix false positive KASAN warning on suspend/resume Dmitry Vyukov <dvyukov@google.com> - 2016-12-02 10:50 +0100
Re: [PATCH v2] x86/suspend: fix false positive KASAN warning on suspend/resume Pavel Machek <pavel@ucw.cz> - 2016-12-02 14:00 +0100
Re: [PATCH v2] x86/suspend: fix false positive KASAN warning on suspend/resume Dmitry Vyukov <dvyukov@google.com> - 2016-12-02 15:10 +0100
Re: [PATCH v2] x86/suspend: fix false positive KASAN warning on suspend/resume Josh Poimboeuf <jpoimboe@redhat.com> - 2016-12-02 15:10 +0100
[PATCH v3] x86/suspend: fix false positive KASAN warning on suspend/resume Josh Poimboeuf <jpoimboe@redhat.com> - 2016-12-02 15:50 +0100
Re: [PATCH v3] x86/suspend: fix false positive KASAN warning on suspend/resume Josh Poimboeuf <jpoimboe@redhat.com> - 2016-12-02 16:10 +0100
[PATCH v4] x86/suspend: fix false positive KASAN warning on suspend/resume Josh Poimboeuf <jpoimboe@redhat.com> - 2016-12-02 18:50 +0100
Re: [PATCH v4] x86/suspend: fix false positive KASAN warning on suspend/resume Pavel Machek <pavel@ucw.cz> - 2016-12-02 22:10 +0100
Re: [PATCH v4] x86/suspend: fix false positive KASAN warning on suspend/resume Josh Poimboeuf <jpoimboe@redhat.com> - 2016-12-02 23:00 +0100
Re: [PATCH v4] x86/suspend: fix false positive KASAN warning on suspend/resume "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2016-12-08 01:20 +0100
Page 1 of 2 [1] 2 Next page →
| From | Scott Bauer <scott.bauer@intel.com> |
|---|---|
| Date | 2016-11-29 19:30 +0100 |
| Subject | BUG: KASAN: stack-out-of-bounds in unwind_get_return_address |
| Message-ID | <sIVke-3Ce-19@gated-at.bofh.it> |
This is super easy to repro ontop of 4.9-rc7: run pm-suspend and it hits every time [ 968.667086] ================================================================== [ 968.667091] BUG: KASAN: stack-out-of-bounds in unwind_get_return_address+0x11d/0x130 at addr ffff8803867d7878 [ 968.667092] Read of size 8 by task pm-suspend/7774 [ 968.667095] page:ffffea000e19f5c0 count:0 mapcount:0 mapping: (null) index:0x0 [ 968.667096] flags: 0x2ffff0000000000() [ 968.667097] page dumped because: kasan: bad access detected [ 968.667099] CPU: 0 PID: 7774 Comm: pm-suspend Tainted: G B 4.9.0-rc7+ #8 [ 968.667100] Hardware name: Gigabyte Technology Co., Ltd. Z170X-UD5/Z170X-UD5-CF, BIOS F5 03/07/2016 [ 968.667102] ffff8803867d7468 ffffffffb4c0d051 ffff8803867d7500 ffff8803867d7878 [ 968.667103] ffff8803867d74f0 ffffffffb45cbe34 ffffffffb4e64136 ffffffffb4510d42 [ 968.667105] ffff8803828c3f4c 0000000000000097 0000000041b58ab3 ffffffffb6192731 [ 968.667105] Call Trace: [ 968.667108] [<ffffffffb4c0d051>] dump_stack+0x63/0x82 [ 968.667110] [<ffffffffb45cbe34>] kasan_report_error+0x4b4/0x4e0 [ 968.667112] [<ffffffffb4e64136>] ? acpi_hw_read_port+0xd0/0x1ea [ 968.667113] [<ffffffffb4510d42>] ? kfree_const+0x22/0x30 [ 968.667114] [<ffffffffb4e64066>] ? acpi_hw_validate_io_request+0x1a6/0x1a6 [ 968.667116] [<ffffffffb45cc011>] __asan_report_load8_noabort+0x61/0x70 [ 968.667117] [<ffffffffb411a29d>] ? unwind_get_return_address+0x11d/0x130 [ 968.667118] [<ffffffffb411a29d>] unwind_get_return_address+0x11d/0x130 [ 968.667119] [<ffffffffb411a497>] ? unwind_next_frame+0x97/0xf0 [ 968.667120] [<ffffffffb40b01e2>] __save_stack_trace+0x92/0x100 [ 968.667122] [<ffffffffb40b026b>] save_stack_trace+0x1b/0x20 [ 968.667123] [<ffffffffb45cac76>] save_stack+0x46/0xd0 [ 968.667124] [<ffffffffb40b026b>] ? save_stack_trace+0x1b/0x20 [ 968.667125] [<ffffffffb45cac76>] ? save_stack+0x46/0xd0 [ 968.667126] [<ffffffffb45caeed>] ? kasan_kmalloc+0xad/0xe0 [ 968.667127] [<ffffffffb45cb432>] ? kasan_slab_alloc+0x12/0x20 [ 968.667128] [<ffffffffb4e62d56>] ? acpi_hw_read+0x2b6/0x3aa [ 968.667129] [<ffffffffb4e62aa0>] ? acpi_hw_validate_register+0x20b/0x20b [ 968.667131] [<ffffffffb4e642c2>] ? acpi_hw_write_port+0x72/0xc7 [ 968.667132] [<ffffffffb4e63108>] ? acpi_hw_write+0x11f/0x15f [ 968.667133] [<ffffffffb4e62fe9>] ? acpi_hw_read_multiple+0x19f/0x19f [ 968.667134] [<ffffffffb45cb065>] ? memcpy+0x45/0x50 [ 968.667135] [<ffffffffb4e642c2>] ? acpi_hw_write_port+0x72/0xc7 [ 968.667136] [<ffffffffb4e63108>] ? acpi_hw_write+0x11f/0x15f [ 968.667137] [<ffffffffb4e62fe9>] ? acpi_hw_read_multiple+0x19f/0x19f [ 968.667138] [<ffffffffb45cad86>] ? kasan_unpoison_shadow+0x36/0x50 [ 968.667140] [<ffffffffb45caeed>] kasan_kmalloc+0xad/0xe0 [ 968.667141] [<ffffffffb45cb432>] kasan_slab_alloc+0x12/0x20 [ 968.667142] [<ffffffffb45c757c>] kmem_cache_alloc_trace+0xbc/0x1e0 [ 968.667143] [<ffffffffb4e64de2>] ? acpi_get_sleep_type_data+0x9a/0x578 [ 968.667144] [<ffffffffb4e64de2>] acpi_get_sleep_type_data+0x9a/0x578 [ 968.667146] [<ffffffffb4e63bc9>] acpi_hw_legacy_wake_prep+0x88/0x22c [ 968.667147] [<ffffffffb4e63b41>] ? acpi_hw_legacy_sleep+0x3c7/0x3c7 [ 968.667148] [<ffffffffb4e64904>] ? acpi_write_bit_register+0x28d/0x2d3 [ 968.667149] [<ffffffffb4e64677>] ? acpi_read_bit_register+0x19b/0x19b [ 968.667150] [<ffffffffb4e6555d>] acpi_hw_sleep_dispatch+0xb5/0xba [ 968.667151] [<ffffffffb4e65579>] acpi_leave_sleep_state_prep+0x17/0x19 [ 968.667153] [<ffffffffb4e0e1d4>] acpi_suspend_enter+0x154/0x1e0 [ 968.667154] [<ffffffffb4e0e080>] ? trace_suspend_resume+0xe8/0xe8 [ 968.667156] [<ffffffffb4262539>] suspend_devices_and_enter+0xb09/0xdb0 [ 968.667157] [<ffffffffb44a6069>] ? printk+0xa8/0xd8 [ 968.667158] [<ffffffffb4261a30>] ? arch_suspend_enable_irqs+0x20/0x20 [ 968.667159] [<ffffffffb4260815>] ? try_to_freeze_tasks+0x295/0x600 [ 968.667160] [<ffffffffb4262ea9>] pm_suspend+0x6c9/0x780 [ 968.667162] [<ffffffffb4244010>] ? finish_wait+0x1f0/0x1f0 [ 968.667163] [<ffffffffb42627e0>] ? suspend_devices_and_enter+0xdb0/0xdb0 [ 968.667164] [<ffffffffb425fe02>] state_store+0xa2/0x120 [ 968.667165] [<ffffffffb4c12ca0>] ? kobj_attr_show+0x60/0x60 [ 968.667166] [<ffffffffb4c12cd6>] kobj_attr_store+0x36/0x70 [ 968.667168] [<ffffffffb47b0701>] sysfs_kf_write+0x131/0x200 [ 968.667169] [<ffffffffb47ae0e5>] kernfs_fop_write+0x295/0x3f0 [ 968.667170] [<ffffffffb462aadf>] __vfs_write+0xef/0x760 [ 968.667172] [<ffffffffb454d136>] ? handle_mm_fault+0x1346/0x35e0 [ 968.667173] [<ffffffffb462a9f0>] ? do_iter_readv_writev+0x660/0x660 [ 968.667174] [<ffffffffb454bdf0>] ? __pmd_alloc+0x310/0x310 [ 968.667176] [<ffffffffb47345d0>] ? do_lock_file_wait+0x1e0/0x1e0 [ 968.667178] [<ffffffffb4ad66e8>] ? apparmor_file_permission+0x18/0x20 [ 968.667179] [<ffffffffb4a14773>] ? security_file_permission+0x73/0x1c0 [ 968.667181] [<ffffffffb462ba3d>] ? rw_verify_area+0xbd/0x2b0 [ 968.667182] [<ffffffffb462c069>] vfs_write+0x149/0x4a0 [ 968.667184] [<ffffffffb462f9a9>] SyS_write+0xd9/0x1c0 [ 968.667185] [<ffffffffb462f8d0>] ? SyS_read+0x1c0/0x1c0 [ 968.667187] [<ffffffffb5a708fb>] entry_SYSCALL_64_fastpath+0x1e/0xad [ 968.667188] Memory state around the buggy address: [ 968.667189] ffff8803867d7700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 968.667190] ffff8803867d7780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 968.667191] >ffff8803867d7800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f4 [ 968.667192] ^ [ 968.667192] ffff8803867d7880: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 [ 968.667193] ffff8803867d7900: 00 00 00 f1 f1 f1 f1 04 f4 f4 f4 f3 f3 f3 f3 00 [ 968.667193] ==================================================================
[toc] | [next] | [standalone]
| From | Josh Poimboeuf <jpoimboe@redhat.com> |
|---|---|
| Date | 2016-11-30 19:40 +0100 |
| Message-ID | <sJhXr-1dw-7@gated-at.bofh.it> |
| In reply to | #1532634 |
On Tue, Nov 29, 2016 at 11:13:01AM -0700, Scott Bauer wrote:
> This is super easy to repro ontop of 4.9-rc7:
> run pm-suspend and it hits every time
>
>
> [ 968.667086] ==================================================================
> [ 968.667091] BUG: KASAN: stack-out-of-bounds in unwind_get_return_address+0x11d/0x130 at addr ffff8803867d7878
> [ 968.667092] Read of size 8 by task pm-suspend/7774
> [ 968.667095] page:ffffea000e19f5c0 count:0 mapcount:0 mapping: (null) index:0x0
> [ 968.667096] flags: 0x2ffff0000000000()
> [ 968.667097] page dumped because: kasan: bad access detected
Thanks for reporting this. I think it's a false positive caused by the
fact that the suspend and resume happen at different contexts.
Can you test if this patch fixes it?
diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
index 4858733..62bd046 100644
--- a/arch/x86/kernel/acpi/sleep.c
+++ b/arch/x86/kernel/acpi/sleep.c
@@ -115,6 +115,9 @@ int x86_acpi_suspend_lowlevel(void)
pause_graph_tracing();
do_suspend_lowlevel();
unpause_graph_tracing();
+
+ kasan_unpoison_stack_below_sp();
+
return 0;
}
diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 820c0ad..ca36126 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -45,6 +45,12 @@ void kasan_unpoison_shadow(const void *address, size_t size);
void kasan_unpoison_task_stack(struct task_struct *task);
void kasan_unpoison_stack_above_sp_to(const void *watermark);
+asmlinkage void kasan_unpoison_task_stack_below(const void *watermark);
+
+static inline void kasan_unpoison_stack_below_sp(void)
+{
+ kasan_unpoison_task_stack_below(__builtin_frame_address(0));
+}
void kasan_alloc_pages(struct page *page, unsigned int order);
void kasan_free_pages(struct page *page, unsigned int order);
[toc] | [prev] | [next] | [standalone]
| From | Scott Bauer <scott.bauer@intel.com> |
|---|---|
| Date | 2016-11-30 20:10 +0100 |
| Message-ID | <sJiqu-1CH-13@gated-at.bofh.it> |
| In reply to | #1533496 |
On Wed, Nov 30, 2016 at 12:35:07PM -0600, Josh Poimboeuf wrote:
> On Tue, Nov 29, 2016 at 11:13:01AM -0700, Scott Bauer wrote:
> > This is super easy to repro ontop of 4.9-rc7:
> > run pm-suspend and it hits every time
> >
> >
> > [ 968.667086] ==================================================================
> > [ 968.667091] BUG: KASAN: stack-out-of-bounds in unwind_get_return_address+0x11d/0x130 at addr ffff8803867d7878
> > [ 968.667092] Read of size 8 by task pm-suspend/7774
> > [ 968.667095] page:ffffea000e19f5c0 count:0 mapcount:0 mapping: (null) index:0x0
> > [ 968.667096] flags: 0x2ffff0000000000()
> > [ 968.667097] page dumped because: kasan: bad access detected
>
> Thanks for reporting this. I think it's a false positive caused by the
> fact that the suspend and resume happen at different contexts.
>
> Can you test if this patch fixes it?
>
> diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
> index 4858733..62bd046 100644
> --- a/arch/x86/kernel/acpi/sleep.c
> +++ b/arch/x86/kernel/acpi/sleep.c
> @@ -115,6 +115,9 @@ int x86_acpi_suspend_lowlevel(void)
> pause_graph_tracing();
> do_suspend_lowlevel();
> unpause_graph_tracing();
> +
> + kasan_unpoison_stack_below_sp();
> +
> return 0;
> }
>
> diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> index 820c0ad..ca36126 100644
> --- a/include/linux/kasan.h
> +++ b/include/linux/kasan.h
> @@ -45,6 +45,12 @@ void kasan_unpoison_shadow(const void *address, size_t size);
>
> void kasan_unpoison_task_stack(struct task_struct *task);
> void kasan_unpoison_stack_above_sp_to(const void *watermark);
> +asmlinkage void kasan_unpoison_task_stack_below(const void *watermark);
> +
> +static inline void kasan_unpoison_stack_below_sp(void)
> +{
> + kasan_unpoison_task_stack_below(__builtin_frame_address(0));
> +}
>
> void kasan_alloc_pages(struct page *page, unsigned int order);
> void kasan_free_pages(struct page *page, unsigned int order);
Thanks for the quick turn-around. This patch worked for me. You can add me as
tested by if you need.
[toc] | [prev] | [next] | [standalone]
| From | Josh Poimboeuf <jpoimboe@redhat.com> |
|---|---|
| Date | 2016-12-01 00:20 +0100 |
| Subject | [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume |
| Message-ID | <sJmkp-4c1-1@gated-at.bofh.it> |
| In reply to | #1533516 |
Resuming from a suspend operation is showing a KASAN false positive
warning:
BUG: KASAN: stack-out-of-bounds in unwind_get_return_address+0x11d/0x130 at addr ffff8803867d7878
Read of size 8 by task pm-suspend/7774
page:ffffea000e19f5c0 count:0 mapcount:0 mapping: (null) index:0x0
flags: 0x2ffff0000000000()
page dumped because: kasan: bad access detected
CPU: 0 PID: 7774 Comm: pm-suspend Tainted: G B 4.9.0-rc7+ #8
Hardware name: Gigabyte Technology Co., Ltd. Z170X-UD5/Z170X-UD5-CF, BIOS F5 03/07/2016
ffff8803867d7468 ffffffffb4c0d051 ffff8803867d7500 ffff8803867d7878
ffff8803867d74f0 ffffffffb45cbe34 ffffffffb4e64136 ffffffffb4510d42
ffff8803828c3f4c 0000000000000097 0000000041b58ab3 ffffffffb6192731
Call Trace:
dump_stack+0x63/0x82
kasan_report_error+0x4b4/0x4e0
? acpi_hw_read_port+0xd0/0x1ea
? kfree_const+0x22/0x30
? acpi_hw_validate_io_request+0x1a6/0x1a6
__asan_report_load8_noabort+0x61/0x70
? unwind_get_return_address+0x11d/0x130
unwind_get_return_address+0x11d/0x130
? unwind_next_frame+0x97/0xf0
__save_stack_trace+0x92/0x100
save_stack_trace+0x1b/0x20
save_stack+0x46/0xd0
? save_stack_trace+0x1b/0x20
? save_stack+0x46/0xd0
? kasan_kmalloc+0xad/0xe0
? kasan_slab_alloc+0x12/0x20
? acpi_hw_read+0x2b6/0x3aa
? acpi_hw_validate_register+0x20b/0x20b
? acpi_hw_write_port+0x72/0xc7
? acpi_hw_write+0x11f/0x15f
? acpi_hw_read_multiple+0x19f/0x19f
? memcpy+0x45/0x50
? acpi_hw_write_port+0x72/0xc7
? acpi_hw_write+0x11f/0x15f
? acpi_hw_read_multiple+0x19f/0x19f
? kasan_unpoison_shadow+0x36/0x50
kasan_kmalloc+0xad/0xe0
kasan_slab_alloc+0x12/0x20
kmem_cache_alloc_trace+0xbc/0x1e0
? acpi_get_sleep_type_data+0x9a/0x578
acpi_get_sleep_type_data+0x9a/0x578
acpi_hw_legacy_wake_prep+0x88/0x22c
? acpi_hw_legacy_sleep+0x3c7/0x3c7
? acpi_write_bit_register+0x28d/0x2d3
? acpi_read_bit_register+0x19b/0x19b
acpi_hw_sleep_dispatch+0xb5/0xba
acpi_leave_sleep_state_prep+0x17/0x19
acpi_suspend_enter+0x154/0x1e0
? trace_suspend_resume+0xe8/0xe8
suspend_devices_and_enter+0xb09/0xdb0
? printk+0xa8/0xd8
? arch_suspend_enable_irqs+0x20/0x20
? try_to_freeze_tasks+0x295/0x600
pm_suspend+0x6c9/0x780
? finish_wait+0x1f0/0x1f0
? suspend_devices_and_enter+0xdb0/0xdb0
state_store+0xa2/0x120
? kobj_attr_show+0x60/0x60
kobj_attr_store+0x36/0x70
sysfs_kf_write+0x131/0x200
kernfs_fop_write+0x295/0x3f0
__vfs_write+0xef/0x760
? handle_mm_fault+0x1346/0x35e0
? do_iter_readv_writev+0x660/0x660
? __pmd_alloc+0x310/0x310
? do_lock_file_wait+0x1e0/0x1e0
? apparmor_file_permission+0x18/0x20
? security_file_permission+0x73/0x1c0
? rw_verify_area+0xbd/0x2b0
vfs_write+0x149/0x4a0
SyS_write+0xd9/0x1c0
? SyS_read+0x1c0/0x1c0
entry_SYSCALL_64_fastpath+0x1e/0xad
Memory state around the buggy address:
ffff8803867d7700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8803867d7780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8803867d7800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f4
^
ffff8803867d7880: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
ffff8803867d7900: 00 00 00 f1 f1 f1 f1 04 f4 f4 f4 f3 f3 f3 f3 00
KASAN instrumentation poisons the stack when entering a function and
unpoisons it when exiting the function. However, in the suspend path,
some functions never return, so their stack never gets unpoisoned,
resulting in stale KASAN shadow data which can cause false positive
warnings like the one above.
Reported-by: Scott Bauer <scott.bauer@intel.com>
Tested-by: Scott Bauer <scott.bauer@intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
arch/x86/kernel/acpi/sleep.c | 3 +++
include/linux/kasan.h | 7 +++++++
2 files changed, 10 insertions(+)
diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
index 4858733..62bd046 100644
--- a/arch/x86/kernel/acpi/sleep.c
+++ b/arch/x86/kernel/acpi/sleep.c
@@ -115,6 +115,9 @@ int x86_acpi_suspend_lowlevel(void)
pause_graph_tracing();
do_suspend_lowlevel();
unpause_graph_tracing();
+
+ kasan_unpoison_stack_below_sp();
+
return 0;
}
diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 820c0ad..e0945d5 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -45,6 +45,12 @@ void kasan_unpoison_shadow(const void *address, size_t size);
void kasan_unpoison_task_stack(struct task_struct *task);
void kasan_unpoison_stack_above_sp_to(const void *watermark);
+asmlinkage void kasan_unpoison_task_stack_below(const void *watermark);
+
+static inline void kasan_unpoison_stack_below_sp(void)
+{
+ kasan_unpoison_task_stack_below(__builtin_frame_address(0));
+}
void kasan_alloc_pages(struct page *page, unsigned int order);
void kasan_free_pages(struct page *page, unsigned int order);
@@ -87,6 +93,7 @@ static inline void kasan_unpoison_shadow(const void *address, size_t size) {}
static inline void kasan_unpoison_task_stack(struct task_struct *task) {}
static inline void kasan_unpoison_stack_above_sp_to(const void *watermark) {}
+static inline void kasan_unpoison_stack_below_sp(void) {}
static inline void kasan_enable_current(void) {}
static inline void kasan_disable_current(void) {}
--
2.7.4
[toc] | [prev] | [next] | [standalone]
| From | "Rafael J. Wysocki" <rafael@kernel.org> |
|---|---|
| Date | 2016-12-01 15:10 +0100 |
| Subject | Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume |
| Message-ID | <sJAdJ-4Rh-41@gated-at.bofh.it> |
| In reply to | #1533667 |
On Thu, Dec 1, 2016 at 12:10 AM, Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> Resuming from a suspend operation is showing a KASAN false positive
> warning:
>
> BUG: KASAN: stack-out-of-bounds in unwind_get_return_address+0x11d/0x130 at addr ffff8803867d7878
> Read of size 8 by task pm-suspend/7774
> page:ffffea000e19f5c0 count:0 mapcount:0 mapping: (null) index:0x0
> flags: 0x2ffff0000000000()
> page dumped because: kasan: bad access detected
> CPU: 0 PID: 7774 Comm: pm-suspend Tainted: G B 4.9.0-rc7+ #8
> Hardware name: Gigabyte Technology Co., Ltd. Z170X-UD5/Z170X-UD5-CF, BIOS F5 03/07/2016
> ffff8803867d7468 ffffffffb4c0d051 ffff8803867d7500 ffff8803867d7878
> ffff8803867d74f0 ffffffffb45cbe34 ffffffffb4e64136 ffffffffb4510d42
> ffff8803828c3f4c 0000000000000097 0000000041b58ab3 ffffffffb6192731
> Call Trace:
> dump_stack+0x63/0x82
> kasan_report_error+0x4b4/0x4e0
> ? acpi_hw_read_port+0xd0/0x1ea
> ? kfree_const+0x22/0x30
> ? acpi_hw_validate_io_request+0x1a6/0x1a6
> __asan_report_load8_noabort+0x61/0x70
> ? unwind_get_return_address+0x11d/0x130
> unwind_get_return_address+0x11d/0x130
> ? unwind_next_frame+0x97/0xf0
> __save_stack_trace+0x92/0x100
> save_stack_trace+0x1b/0x20
> save_stack+0x46/0xd0
> ? save_stack_trace+0x1b/0x20
> ? save_stack+0x46/0xd0
> ? kasan_kmalloc+0xad/0xe0
> ? kasan_slab_alloc+0x12/0x20
> ? acpi_hw_read+0x2b6/0x3aa
> ? acpi_hw_validate_register+0x20b/0x20b
> ? acpi_hw_write_port+0x72/0xc7
> ? acpi_hw_write+0x11f/0x15f
> ? acpi_hw_read_multiple+0x19f/0x19f
> ? memcpy+0x45/0x50
> ? acpi_hw_write_port+0x72/0xc7
> ? acpi_hw_write+0x11f/0x15f
> ? acpi_hw_read_multiple+0x19f/0x19f
> ? kasan_unpoison_shadow+0x36/0x50
> kasan_kmalloc+0xad/0xe0
> kasan_slab_alloc+0x12/0x20
> kmem_cache_alloc_trace+0xbc/0x1e0
> ? acpi_get_sleep_type_data+0x9a/0x578
> acpi_get_sleep_type_data+0x9a/0x578
> acpi_hw_legacy_wake_prep+0x88/0x22c
> ? acpi_hw_legacy_sleep+0x3c7/0x3c7
> ? acpi_write_bit_register+0x28d/0x2d3
> ? acpi_read_bit_register+0x19b/0x19b
> acpi_hw_sleep_dispatch+0xb5/0xba
> acpi_leave_sleep_state_prep+0x17/0x19
> acpi_suspend_enter+0x154/0x1e0
> ? trace_suspend_resume+0xe8/0xe8
> suspend_devices_and_enter+0xb09/0xdb0
> ? printk+0xa8/0xd8
> ? arch_suspend_enable_irqs+0x20/0x20
> ? try_to_freeze_tasks+0x295/0x600
> pm_suspend+0x6c9/0x780
> ? finish_wait+0x1f0/0x1f0
> ? suspend_devices_and_enter+0xdb0/0xdb0
> state_store+0xa2/0x120
> ? kobj_attr_show+0x60/0x60
> kobj_attr_store+0x36/0x70
> sysfs_kf_write+0x131/0x200
> kernfs_fop_write+0x295/0x3f0
> __vfs_write+0xef/0x760
> ? handle_mm_fault+0x1346/0x35e0
> ? do_iter_readv_writev+0x660/0x660
> ? __pmd_alloc+0x310/0x310
> ? do_lock_file_wait+0x1e0/0x1e0
> ? apparmor_file_permission+0x18/0x20
> ? security_file_permission+0x73/0x1c0
> ? rw_verify_area+0xbd/0x2b0
> vfs_write+0x149/0x4a0
> SyS_write+0xd9/0x1c0
> ? SyS_read+0x1c0/0x1c0
> entry_SYSCALL_64_fastpath+0x1e/0xad
> Memory state around the buggy address:
> ffff8803867d7700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> ffff8803867d7780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> >ffff8803867d7800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f4
> ^
> ffff8803867d7880: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
> ffff8803867d7900: 00 00 00 f1 f1 f1 f1 04 f4 f4 f4 f3 f3 f3 f3 00
>
> KASAN instrumentation poisons the stack when entering a function and
> unpoisons it when exiting the function. However, in the suspend path,
> some functions never return, so their stack never gets unpoisoned,
> resulting in stale KASAN shadow data which can cause false positive
> warnings like the one above.
>
> Reported-by: Scott Bauer <scott.bauer@intel.com>
> Tested-by: Scott Bauer <scott.bauer@intel.com>
> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
> ---
> arch/x86/kernel/acpi/sleep.c | 3 +++
> include/linux/kasan.h | 7 +++++++
> 2 files changed, 10 insertions(+)
>
> diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
> index 4858733..62bd046 100644
> --- a/arch/x86/kernel/acpi/sleep.c
> +++ b/arch/x86/kernel/acpi/sleep.c
> @@ -115,6 +115,9 @@ int x86_acpi_suspend_lowlevel(void)
> pause_graph_tracing();
> do_suspend_lowlevel();
> unpause_graph_tracing();
> +
> + kasan_unpoison_stack_below_sp();
> +
> return 0;
> }
>
> diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> index 820c0ad..e0945d5 100644
> --- a/include/linux/kasan.h
> +++ b/include/linux/kasan.h
> @@ -45,6 +45,12 @@ void kasan_unpoison_shadow(const void *address, size_t size);
>
> void kasan_unpoison_task_stack(struct task_struct *task);
> void kasan_unpoison_stack_above_sp_to(const void *watermark);
> +asmlinkage void kasan_unpoison_task_stack_below(const void *watermark);
> +
> +static inline void kasan_unpoison_stack_below_sp(void)
> +{
> + kasan_unpoison_task_stack_below(__builtin_frame_address(0));
> +}
>
> void kasan_alloc_pages(struct page *page, unsigned int order);
> void kasan_free_pages(struct page *page, unsigned int order);
> @@ -87,6 +93,7 @@ static inline void kasan_unpoison_shadow(const void *address, size_t size) {}
>
> static inline void kasan_unpoison_task_stack(struct task_struct *task) {}
> static inline void kasan_unpoison_stack_above_sp_to(const void *watermark) {}
> +static inline void kasan_unpoison_stack_below_sp(void) {}
>
> static inline void kasan_enable_current(void) {}
> static inline void kasan_disable_current(void) {}
> --
Looks OK to me.
Whom do you expect to apply this?
Thanks,
Rafael
[toc] | [prev] | [next] | [standalone]
| From | Josh Poimboeuf <jpoimboe@redhat.com> |
|---|---|
| Date | 2016-12-01 18:00 +0100 |
| Subject | Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume |
| Message-ID | <sJCSe-6Dp-31@gated-at.bofh.it> |
| In reply to | #1534127 |
On Thu, Dec 01, 2016 at 03:04:22PM +0100, Rafael J. Wysocki wrote:
> On Thu, Dec 1, 2016 at 12:10 AM, Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> > Resuming from a suspend operation is showing a KASAN false positive
> > warning:
> >
> > BUG: KASAN: stack-out-of-bounds in unwind_get_return_address+0x11d/0x130 at addr ffff8803867d7878
> > Read of size 8 by task pm-suspend/7774
> > page:ffffea000e19f5c0 count:0 mapcount:0 mapping: (null) index:0x0
> > flags: 0x2ffff0000000000()
> > page dumped because: kasan: bad access detected
> > CPU: 0 PID: 7774 Comm: pm-suspend Tainted: G B 4.9.0-rc7+ #8
> > Hardware name: Gigabyte Technology Co., Ltd. Z170X-UD5/Z170X-UD5-CF, BIOS F5 03/07/2016
> > ffff8803867d7468 ffffffffb4c0d051 ffff8803867d7500 ffff8803867d7878
> > ffff8803867d74f0 ffffffffb45cbe34 ffffffffb4e64136 ffffffffb4510d42
> > ffff8803828c3f4c 0000000000000097 0000000041b58ab3 ffffffffb6192731
> > Call Trace:
> > dump_stack+0x63/0x82
> > kasan_report_error+0x4b4/0x4e0
> > ? acpi_hw_read_port+0xd0/0x1ea
> > ? kfree_const+0x22/0x30
> > ? acpi_hw_validate_io_request+0x1a6/0x1a6
> > __asan_report_load8_noabort+0x61/0x70
> > ? unwind_get_return_address+0x11d/0x130
> > unwind_get_return_address+0x11d/0x130
> > ? unwind_next_frame+0x97/0xf0
> > __save_stack_trace+0x92/0x100
> > save_stack_trace+0x1b/0x20
> > save_stack+0x46/0xd0
> > ? save_stack_trace+0x1b/0x20
> > ? save_stack+0x46/0xd0
> > ? kasan_kmalloc+0xad/0xe0
> > ? kasan_slab_alloc+0x12/0x20
> > ? acpi_hw_read+0x2b6/0x3aa
> > ? acpi_hw_validate_register+0x20b/0x20b
> > ? acpi_hw_write_port+0x72/0xc7
> > ? acpi_hw_write+0x11f/0x15f
> > ? acpi_hw_read_multiple+0x19f/0x19f
> > ? memcpy+0x45/0x50
> > ? acpi_hw_write_port+0x72/0xc7
> > ? acpi_hw_write+0x11f/0x15f
> > ? acpi_hw_read_multiple+0x19f/0x19f
> > ? kasan_unpoison_shadow+0x36/0x50
> > kasan_kmalloc+0xad/0xe0
> > kasan_slab_alloc+0x12/0x20
> > kmem_cache_alloc_trace+0xbc/0x1e0
> > ? acpi_get_sleep_type_data+0x9a/0x578
> > acpi_get_sleep_type_data+0x9a/0x578
> > acpi_hw_legacy_wake_prep+0x88/0x22c
> > ? acpi_hw_legacy_sleep+0x3c7/0x3c7
> > ? acpi_write_bit_register+0x28d/0x2d3
> > ? acpi_read_bit_register+0x19b/0x19b
> > acpi_hw_sleep_dispatch+0xb5/0xba
> > acpi_leave_sleep_state_prep+0x17/0x19
> > acpi_suspend_enter+0x154/0x1e0
> > ? trace_suspend_resume+0xe8/0xe8
> > suspend_devices_and_enter+0xb09/0xdb0
> > ? printk+0xa8/0xd8
> > ? arch_suspend_enable_irqs+0x20/0x20
> > ? try_to_freeze_tasks+0x295/0x600
> > pm_suspend+0x6c9/0x780
> > ? finish_wait+0x1f0/0x1f0
> > ? suspend_devices_and_enter+0xdb0/0xdb0
> > state_store+0xa2/0x120
> > ? kobj_attr_show+0x60/0x60
> > kobj_attr_store+0x36/0x70
> > sysfs_kf_write+0x131/0x200
> > kernfs_fop_write+0x295/0x3f0
> > __vfs_write+0xef/0x760
> > ? handle_mm_fault+0x1346/0x35e0
> > ? do_iter_readv_writev+0x660/0x660
> > ? __pmd_alloc+0x310/0x310
> > ? do_lock_file_wait+0x1e0/0x1e0
> > ? apparmor_file_permission+0x18/0x20
> > ? security_file_permission+0x73/0x1c0
> > ? rw_verify_area+0xbd/0x2b0
> > vfs_write+0x149/0x4a0
> > SyS_write+0xd9/0x1c0
> > ? SyS_read+0x1c0/0x1c0
> > entry_SYSCALL_64_fastpath+0x1e/0xad
> > Memory state around the buggy address:
> > ffff8803867d7700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> > ffff8803867d7780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> > >ffff8803867d7800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f4
> > ^
> > ffff8803867d7880: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
> > ffff8803867d7900: 00 00 00 f1 f1 f1 f1 04 f4 f4 f4 f3 f3 f3 f3 00
> >
> > KASAN instrumentation poisons the stack when entering a function and
> > unpoisons it when exiting the function. However, in the suspend path,
> > some functions never return, so their stack never gets unpoisoned,
> > resulting in stale KASAN shadow data which can cause false positive
> > warnings like the one above.
> >
> > Reported-by: Scott Bauer <scott.bauer@intel.com>
> > Tested-by: Scott Bauer <scott.bauer@intel.com>
> > Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
> > ---
> > arch/x86/kernel/acpi/sleep.c | 3 +++
> > include/linux/kasan.h | 7 +++++++
> > 2 files changed, 10 insertions(+)
> >
> > diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
> > index 4858733..62bd046 100644
> > --- a/arch/x86/kernel/acpi/sleep.c
> > +++ b/arch/x86/kernel/acpi/sleep.c
> > @@ -115,6 +115,9 @@ int x86_acpi_suspend_lowlevel(void)
> > pause_graph_tracing();
> > do_suspend_lowlevel();
> > unpause_graph_tracing();
> > +
> > + kasan_unpoison_stack_below_sp();
> > +
> > return 0;
> > }
> >
> > diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> > index 820c0ad..e0945d5 100644
> > --- a/include/linux/kasan.h
> > +++ b/include/linux/kasan.h
> > @@ -45,6 +45,12 @@ void kasan_unpoison_shadow(const void *address, size_t size);
> >
> > void kasan_unpoison_task_stack(struct task_struct *task);
> > void kasan_unpoison_stack_above_sp_to(const void *watermark);
> > +asmlinkage void kasan_unpoison_task_stack_below(const void *watermark);
> > +
> > +static inline void kasan_unpoison_stack_below_sp(void)
> > +{
> > + kasan_unpoison_task_stack_below(__builtin_frame_address(0));
> > +}
> >
> > void kasan_alloc_pages(struct page *page, unsigned int order);
> > void kasan_free_pages(struct page *page, unsigned int order);
> > @@ -87,6 +93,7 @@ static inline void kasan_unpoison_shadow(const void *address, size_t size) {}
> >
> > static inline void kasan_unpoison_task_stack(struct task_struct *task) {}
> > static inline void kasan_unpoison_stack_above_sp_to(const void *watermark) {}
> > +static inline void kasan_unpoison_stack_below_sp(void) {}
> >
> > static inline void kasan_enable_current(void) {}
> > static inline void kasan_disable_current(void) {}
> > --
>
> Looks OK to me.
>
> Whom do you expect to apply this?
Assuming it gets an ack from Andrey, can you take it? Or would the tip
tree be better?
--
Josh
[toc] | [prev] | [next] | [standalone]
| From | "Rafael J. Wysocki" <rafael@kernel.org> |
|---|---|
| Date | 2016-12-01 18:10 +0100 |
| Subject | Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume |
| Message-ID | <sJD1U-70r-19@gated-at.bofh.it> |
| In reply to | #1534293 |
On Thu, Dec 1, 2016 at 5:53 PM, Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> On Thu, Dec 01, 2016 at 03:04:22PM +0100, Rafael J. Wysocki wrote:
>> On Thu, Dec 1, 2016 at 12:10 AM, Josh Poimboeuf <jpoimboe@redhat.com> wrote:
>> > Resuming from a suspend operation is showing a KASAN false positive
>> > warning:
>> >
>> > BUG: KASAN: stack-out-of-bounds in unwind_get_return_address+0x11d/0x130 at addr ffff8803867d7878
>> > Read of size 8 by task pm-suspend/7774
>> > page:ffffea000e19f5c0 count:0 mapcount:0 mapping: (null) index:0x0
>> > flags: 0x2ffff0000000000()
>> > page dumped because: kasan: bad access detected
>> > CPU: 0 PID: 7774 Comm: pm-suspend Tainted: G B 4.9.0-rc7+ #8
>> > Hardware name: Gigabyte Technology Co., Ltd. Z170X-UD5/Z170X-UD5-CF, BIOS F5 03/07/2016
>> > ffff8803867d7468 ffffffffb4c0d051 ffff8803867d7500 ffff8803867d7878
>> > ffff8803867d74f0 ffffffffb45cbe34 ffffffffb4e64136 ffffffffb4510d42
>> > ffff8803828c3f4c 0000000000000097 0000000041b58ab3 ffffffffb6192731
>> > Call Trace:
>> > dump_stack+0x63/0x82
>> > kasan_report_error+0x4b4/0x4e0
>> > ? acpi_hw_read_port+0xd0/0x1ea
>> > ? kfree_const+0x22/0x30
>> > ? acpi_hw_validate_io_request+0x1a6/0x1a6
>> > __asan_report_load8_noabort+0x61/0x70
>> > ? unwind_get_return_address+0x11d/0x130
>> > unwind_get_return_address+0x11d/0x130
>> > ? unwind_next_frame+0x97/0xf0
>> > __save_stack_trace+0x92/0x100
>> > save_stack_trace+0x1b/0x20
>> > save_stack+0x46/0xd0
>> > ? save_stack_trace+0x1b/0x20
>> > ? save_stack+0x46/0xd0
>> > ? kasan_kmalloc+0xad/0xe0
>> > ? kasan_slab_alloc+0x12/0x20
>> > ? acpi_hw_read+0x2b6/0x3aa
>> > ? acpi_hw_validate_register+0x20b/0x20b
>> > ? acpi_hw_write_port+0x72/0xc7
>> > ? acpi_hw_write+0x11f/0x15f
>> > ? acpi_hw_read_multiple+0x19f/0x19f
>> > ? memcpy+0x45/0x50
>> > ? acpi_hw_write_port+0x72/0xc7
>> > ? acpi_hw_write+0x11f/0x15f
>> > ? acpi_hw_read_multiple+0x19f/0x19f
>> > ? kasan_unpoison_shadow+0x36/0x50
>> > kasan_kmalloc+0xad/0xe0
>> > kasan_slab_alloc+0x12/0x20
>> > kmem_cache_alloc_trace+0xbc/0x1e0
>> > ? acpi_get_sleep_type_data+0x9a/0x578
>> > acpi_get_sleep_type_data+0x9a/0x578
>> > acpi_hw_legacy_wake_prep+0x88/0x22c
>> > ? acpi_hw_legacy_sleep+0x3c7/0x3c7
>> > ? acpi_write_bit_register+0x28d/0x2d3
>> > ? acpi_read_bit_register+0x19b/0x19b
>> > acpi_hw_sleep_dispatch+0xb5/0xba
>> > acpi_leave_sleep_state_prep+0x17/0x19
>> > acpi_suspend_enter+0x154/0x1e0
>> > ? trace_suspend_resume+0xe8/0xe8
>> > suspend_devices_and_enter+0xb09/0xdb0
>> > ? printk+0xa8/0xd8
>> > ? arch_suspend_enable_irqs+0x20/0x20
>> > ? try_to_freeze_tasks+0x295/0x600
>> > pm_suspend+0x6c9/0x780
>> > ? finish_wait+0x1f0/0x1f0
>> > ? suspend_devices_and_enter+0xdb0/0xdb0
>> > state_store+0xa2/0x120
>> > ? kobj_attr_show+0x60/0x60
>> > kobj_attr_store+0x36/0x70
>> > sysfs_kf_write+0x131/0x200
>> > kernfs_fop_write+0x295/0x3f0
>> > __vfs_write+0xef/0x760
>> > ? handle_mm_fault+0x1346/0x35e0
>> > ? do_iter_readv_writev+0x660/0x660
>> > ? __pmd_alloc+0x310/0x310
>> > ? do_lock_file_wait+0x1e0/0x1e0
>> > ? apparmor_file_permission+0x18/0x20
>> > ? security_file_permission+0x73/0x1c0
>> > ? rw_verify_area+0xbd/0x2b0
>> > vfs_write+0x149/0x4a0
>> > SyS_write+0xd9/0x1c0
>> > ? SyS_read+0x1c0/0x1c0
>> > entry_SYSCALL_64_fastpath+0x1e/0xad
>> > Memory state around the buggy address:
>> > ffff8803867d7700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>> > ffff8803867d7780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>> > >ffff8803867d7800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f4
>> > ^
>> > ffff8803867d7880: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
>> > ffff8803867d7900: 00 00 00 f1 f1 f1 f1 04 f4 f4 f4 f3 f3 f3 f3 00
>> >
>> > KASAN instrumentation poisons the stack when entering a function and
>> > unpoisons it when exiting the function. However, in the suspend path,
>> > some functions never return, so their stack never gets unpoisoned,
>> > resulting in stale KASAN shadow data which can cause false positive
>> > warnings like the one above.
>> >
>> > Reported-by: Scott Bauer <scott.bauer@intel.com>
>> > Tested-by: Scott Bauer <scott.bauer@intel.com>
>> > Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
>> > ---
>> > arch/x86/kernel/acpi/sleep.c | 3 +++
>> > include/linux/kasan.h | 7 +++++++
>> > 2 files changed, 10 insertions(+)
>> >
>> > diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
>> > index 4858733..62bd046 100644
>> > --- a/arch/x86/kernel/acpi/sleep.c
>> > +++ b/arch/x86/kernel/acpi/sleep.c
>> > @@ -115,6 +115,9 @@ int x86_acpi_suspend_lowlevel(void)
>> > pause_graph_tracing();
>> > do_suspend_lowlevel();
>> > unpause_graph_tracing();
>> > +
>> > + kasan_unpoison_stack_below_sp();
>> > +
>> > return 0;
>> > }
>> >
>> > diff --git a/include/linux/kasan.h b/include/linux/kasan.h
>> > index 820c0ad..e0945d5 100644
>> > --- a/include/linux/kasan.h
>> > +++ b/include/linux/kasan.h
>> > @@ -45,6 +45,12 @@ void kasan_unpoison_shadow(const void *address, size_t size);
>> >
>> > void kasan_unpoison_task_stack(struct task_struct *task);
>> > void kasan_unpoison_stack_above_sp_to(const void *watermark);
>> > +asmlinkage void kasan_unpoison_task_stack_below(const void *watermark);
>> > +
>> > +static inline void kasan_unpoison_stack_below_sp(void)
>> > +{
>> > + kasan_unpoison_task_stack_below(__builtin_frame_address(0));
>> > +}
>> >
>> > void kasan_alloc_pages(struct page *page, unsigned int order);
>> > void kasan_free_pages(struct page *page, unsigned int order);
>> > @@ -87,6 +93,7 @@ static inline void kasan_unpoison_shadow(const void *address, size_t size) {}
>> >
>> > static inline void kasan_unpoison_task_stack(struct task_struct *task) {}
>> > static inline void kasan_unpoison_stack_above_sp_to(const void *watermark) {}
>> > +static inline void kasan_unpoison_stack_below_sp(void) {}
>> >
>> > static inline void kasan_enable_current(void) {}
>> > static inline void kasan_disable_current(void) {}
>> > --
>>
>> Looks OK to me.
>>
>> Whom do you expect to apply this?
>
> Assuming it gets an ack from Andrey, can you take it? Or would the tip
> tree be better?
I can take it unless anyone else wants to take care of it. :-)
Thanks,
Rafael
[toc] | [prev] | [next] | [standalone]
| From | Ingo Molnar <mingo@kernel.org> |
|---|---|
| Date | 2016-12-02 11:20 +0100 |
| Subject | Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume |
| Message-ID | <sJT6F-2yH-13@gated-at.bofh.it> |
| In reply to | #1534302 |
* Rafael J. Wysocki <rafael@kernel.org> wrote: > >> Looks OK to me. > >> > >> Whom do you expect to apply this? > > > > Assuming it gets an ack from Andrey, can you take it? Or would the tip > > tree be better? > > I can take it unless anyone else wants to take care of it. :-) Please pick up the fixes in this thread. Thanks! Ingo
[toc] | [prev] | [next] | [standalone]
| From | Josh Poimboeuf <jpoimboe@redhat.com> |
|---|---|
| Date | 2016-12-01 16:00 +0100 |
| Subject | Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume |
| Message-ID | <sJB05-5a9-15@gated-at.bofh.it> |
| In reply to | #1533667 |
On Thu, Dec 01, 2016 at 12:05:34PM +0300, Andrey Ryabinin wrote: > > > On 12/01/2016 02:10 AM, Josh Poimboeuf wrote: > > Resuming from a suspend operation is showing a KASAN false positive > > warning: > > > > > KASAN instrumentation poisons the stack when entering a function and > > unpoisons it when exiting the function. However, in the suspend path, > > some functions never return, so their stack never gets unpoisoned, > > resulting in stale KASAN shadow data which can cause false positive > > warnings like the one above. > > > > Reported-by: Scott Bauer <scott.bauer@intel.com> > > Tested-by: Scott Bauer <scott.bauer@intel.com> > > Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> > > --- > > arch/x86/kernel/acpi/sleep.c | 3 +++ > > include/linux/kasan.h | 7 +++++++ > > 2 files changed, 10 insertions(+) > > > > diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c > > index 4858733..62bd046 100644 > > --- a/arch/x86/kernel/acpi/sleep.c > > +++ b/arch/x86/kernel/acpi/sleep.c > > @@ -115,6 +115,9 @@ int x86_acpi_suspend_lowlevel(void) > > pause_graph_tracing(); > > do_suspend_lowlevel(); > > unpause_graph_tracing(); > > + > > + kasan_unpoison_stack_below_sp(); > > + > > I think this might be too late. We may hit stale poison in the first C function called > after resume (restore_processor_state()). Thus the shadow must be unpoisoned prior such call, > i.e. somewhere in do_suspend_lowlevel() after .Lresume_point. Yeah, I think you're right. Will spin a v2. -- Josh
[toc] | [prev] | [next] | [standalone]
| From | Josh Poimboeuf <jpoimboe@redhat.com> |
|---|---|
| Date | 2016-12-01 17:50 +0100 |
| Subject | Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume |
| Message-ID | <sJCIx-6wt-5@gated-at.bofh.it> |
| In reply to | #1534168 |
On Thu, Dec 01, 2016 at 08:58:21AM -0600, Josh Poimboeuf wrote: > On Thu, Dec 01, 2016 at 12:05:34PM +0300, Andrey Ryabinin wrote: > > > > > > On 12/01/2016 02:10 AM, Josh Poimboeuf wrote: > > > Resuming from a suspend operation is showing a KASAN false positive > > > warning: > > > > > > > > KASAN instrumentation poisons the stack when entering a function and > > > unpoisons it when exiting the function. However, in the suspend path, > > > some functions never return, so their stack never gets unpoisoned, > > > resulting in stale KASAN shadow data which can cause false positive > > > warnings like the one above. > > > > > > Reported-by: Scott Bauer <scott.bauer@intel.com> > > > Tested-by: Scott Bauer <scott.bauer@intel.com> > > > Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> > > > --- > > > arch/x86/kernel/acpi/sleep.c | 3 +++ > > > include/linux/kasan.h | 7 +++++++ > > > 2 files changed, 10 insertions(+) > > > > > > diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c > > > index 4858733..62bd046 100644 > > > --- a/arch/x86/kernel/acpi/sleep.c > > > +++ b/arch/x86/kernel/acpi/sleep.c > > > @@ -115,6 +115,9 @@ int x86_acpi_suspend_lowlevel(void) > > > pause_graph_tracing(); > > > do_suspend_lowlevel(); > > > unpause_graph_tracing(); > > > + > > > + kasan_unpoison_stack_below_sp(); > > > + > > > > I think this might be too late. We may hit stale poison in the first C function called > > after resume (restore_processor_state()). Thus the shadow must be unpoisoned prior such call, > > i.e. somewhere in do_suspend_lowlevel() after .Lresume_point. > > Yeah, I think you're right. Will spin a v2. So I tried calling kasan_unpoison_task_stack_below() from do_suspend_lowlevel(), but it hung on the resume. Presumably because restore_processor_state() does some important setup which would be needed before calling into kasan_unpoison_task_stack_below(). For example, setting up the gs register. So it's a bit of a catch-22. It could probably be fixed properly by rewriting do_suspend_lowlevel() to call restore_processor_state() with the temporary stack before switching to the original stack and doing the unpoison. (And there are some other issues with do_suspend_lowlevel() and I'd love to try taking a scalpel to it. But I have too many knives in the air already to want to try to attempt that right now...) Unless somebody else wants to take a stab at it, my original patch is probably good enough for now, since restore_processor_state() doesn't seem to be triggering any KASAN warnings. -- Josh
[toc] | [prev] | [next] | [standalone]
| From | Dmitry Vyukov <dvyukov@google.com> |
|---|---|
| Date | 2016-12-01 18:00 +0100 |
| Subject | Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume |
| Message-ID | <sJCSe-6Dp-33@gated-at.bofh.it> |
| In reply to | #1534278 |
On Thu, Dec 1, 2016 at 5:45 PM, Josh Poimboeuf <jpoimboe@redhat.com> wrote: > On Thu, Dec 01, 2016 at 08:58:21AM -0600, Josh Poimboeuf wrote: >> On Thu, Dec 01, 2016 at 12:05:34PM +0300, Andrey Ryabinin wrote: >> > >> > >> > On 12/01/2016 02:10 AM, Josh Poimboeuf wrote: >> > > Resuming from a suspend operation is showing a KASAN false positive >> > > warning: >> > > >> > >> > > KASAN instrumentation poisons the stack when entering a function and >> > > unpoisons it when exiting the function. However, in the suspend path, >> > > some functions never return, so their stack never gets unpoisoned, >> > > resulting in stale KASAN shadow data which can cause false positive >> > > warnings like the one above. >> > > >> > > Reported-by: Scott Bauer <scott.bauer@intel.com> >> > > Tested-by: Scott Bauer <scott.bauer@intel.com> >> > > Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> >> > > --- >> > > arch/x86/kernel/acpi/sleep.c | 3 +++ >> > > include/linux/kasan.h | 7 +++++++ >> > > 2 files changed, 10 insertions(+) >> > > >> > > diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c >> > > index 4858733..62bd046 100644 >> > > --- a/arch/x86/kernel/acpi/sleep.c >> > > +++ b/arch/x86/kernel/acpi/sleep.c >> > > @@ -115,6 +115,9 @@ int x86_acpi_suspend_lowlevel(void) >> > > pause_graph_tracing(); >> > > do_suspend_lowlevel(); >> > > unpause_graph_tracing(); >> > > + >> > > + kasan_unpoison_stack_below_sp(); >> > > + >> > >> > I think this might be too late. We may hit stale poison in the first C function called >> > after resume (restore_processor_state()). Thus the shadow must be unpoisoned prior such call, >> > i.e. somewhere in do_suspend_lowlevel() after .Lresume_point. >> >> Yeah, I think you're right. Will spin a v2. > > So I tried calling kasan_unpoison_task_stack_below() from > do_suspend_lowlevel(), but it hung on the resume. Presumably because > restore_processor_state() does some important setup which would be > needed before calling into kasan_unpoison_task_stack_below(). For > example, setting up the gs register. So it's a bit of a catch-22. > > It could probably be fixed properly by rewriting do_suspend_lowlevel() > to call restore_processor_state() with the temporary stack before > switching to the original stack and doing the unpoison. > > (And there are some other issues with do_suspend_lowlevel() and I'd love > to try taking a scalpel to it. But I have too many knives in the air > already to want to try to attempt that right now...) > > Unless somebody else wants to take a stab at it, my original patch is > probably good enough for now, since restore_processor_state() doesn't > seem to be triggering any KASAN warnings. restore_processor_state/__restore_processor_state does not seem to have any local variables, so KASAN does not do any stack checks there. We could disable KASAN instrumentation of the file, or of particular functions. Or we could call kasan_unpoison_shadow() on the stack range before switching to it.
[toc] | [prev] | [next] | [standalone]
| From | Josh Poimboeuf <jpoimboe@redhat.com> |
|---|---|
| Date | 2016-12-01 18:20 +0100 |
| Subject | Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume |
| Message-ID | <sJDbA-78p-27@gated-at.bofh.it> |
| In reply to | #1534294 |
On Thu, Dec 01, 2016 at 05:51:52PM +0100, Dmitry Vyukov wrote: > On Thu, Dec 1, 2016 at 5:45 PM, Josh Poimboeuf <jpoimboe@redhat.com> wrote: > > On Thu, Dec 01, 2016 at 08:58:21AM -0600, Josh Poimboeuf wrote: > >> On Thu, Dec 01, 2016 at 12:05:34PM +0300, Andrey Ryabinin wrote: > >> > > >> > > >> > On 12/01/2016 02:10 AM, Josh Poimboeuf wrote: > >> > > Resuming from a suspend operation is showing a KASAN false positive > >> > > warning: > >> > > > >> > > >> > > KASAN instrumentation poisons the stack when entering a function and > >> > > unpoisons it when exiting the function. However, in the suspend path, > >> > > some functions never return, so their stack never gets unpoisoned, > >> > > resulting in stale KASAN shadow data which can cause false positive > >> > > warnings like the one above. > >> > > > >> > > Reported-by: Scott Bauer <scott.bauer@intel.com> > >> > > Tested-by: Scott Bauer <scott.bauer@intel.com> > >> > > Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> > >> > > --- > >> > > arch/x86/kernel/acpi/sleep.c | 3 +++ > >> > > include/linux/kasan.h | 7 +++++++ > >> > > 2 files changed, 10 insertions(+) > >> > > > >> > > diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c > >> > > index 4858733..62bd046 100644 > >> > > --- a/arch/x86/kernel/acpi/sleep.c > >> > > +++ b/arch/x86/kernel/acpi/sleep.c > >> > > @@ -115,6 +115,9 @@ int x86_acpi_suspend_lowlevel(void) > >> > > pause_graph_tracing(); > >> > > do_suspend_lowlevel(); > >> > > unpause_graph_tracing(); > >> > > + > >> > > + kasan_unpoison_stack_below_sp(); > >> > > + > >> > > >> > I think this might be too late. We may hit stale poison in the first C function called > >> > after resume (restore_processor_state()). Thus the shadow must be unpoisoned prior such call, > >> > i.e. somewhere in do_suspend_lowlevel() after .Lresume_point. > >> > >> Yeah, I think you're right. Will spin a v2. > > > > So I tried calling kasan_unpoison_task_stack_below() from > > do_suspend_lowlevel(), but it hung on the resume. Presumably because > > restore_processor_state() does some important setup which would be > > needed before calling into kasan_unpoison_task_stack_below(). For > > example, setting up the gs register. So it's a bit of a catch-22. > > > > It could probably be fixed properly by rewriting do_suspend_lowlevel() > > to call restore_processor_state() with the temporary stack before > > switching to the original stack and doing the unpoison. > > > > (And there are some other issues with do_suspend_lowlevel() and I'd love > > to try taking a scalpel to it. But I have too many knives in the air > > already to want to try to attempt that right now...) > > > > Unless somebody else wants to take a stab at it, my original patch is > > probably good enough for now, since restore_processor_state() doesn't > > seem to be triggering any KASAN warnings. > > restore_processor_state/__restore_processor_state does not seem to > have any local variables, so KASAN does not do any stack checks there. Actually, looking at the object code, it uses a lot of stack space and has several calls to __asan_report_load*() functions. Probably due to inlining of other functions which have stack variables. > We could disable KASAN instrumentation of the file, or of particular > functions. I don't think that would be sufficient unless it were disabled for __restore_processor_state() and all the functions it calls (and the functions they call, etc), which wouldn't necessarily be straightforward. > Or we could call kasan_unpoison_shadow() on the stack range > before switching to it. I tried that already, but it hung because restore_processor_state() hadn't been called yet (the catch-22 I mentioned aboved). -- Josh
[toc] | [prev] | [next] | [standalone]
| From | Dmitry Vyukov <dvyukov@google.com> |
|---|---|
| Date | 2016-12-01 18:30 +0100 |
| Subject | Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume |
| Message-ID | <sJDlf-7gi-1@gated-at.bofh.it> |
| In reply to | #1534321 |
On Thu, Dec 1, 2016 at 6:13 PM, Josh Poimboeuf <jpoimboe@redhat.com> wrote: > On Thu, Dec 01, 2016 at 05:51:52PM +0100, Dmitry Vyukov wrote: >> On Thu, Dec 1, 2016 at 5:45 PM, Josh Poimboeuf <jpoimboe@redhat.com> wrote: >> > On Thu, Dec 01, 2016 at 08:58:21AM -0600, Josh Poimboeuf wrote: >> >> On Thu, Dec 01, 2016 at 12:05:34PM +0300, Andrey Ryabinin wrote: >> >> > >> >> > >> >> > On 12/01/2016 02:10 AM, Josh Poimboeuf wrote: >> >> > > Resuming from a suspend operation is showing a KASAN false positive >> >> > > warning: >> >> > > >> >> > >> >> > > KASAN instrumentation poisons the stack when entering a function and >> >> > > unpoisons it when exiting the function. However, in the suspend path, >> >> > > some functions never return, so their stack never gets unpoisoned, >> >> > > resulting in stale KASAN shadow data which can cause false positive >> >> > > warnings like the one above. >> >> > > >> >> > > Reported-by: Scott Bauer <scott.bauer@intel.com> >> >> > > Tested-by: Scott Bauer <scott.bauer@intel.com> >> >> > > Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> >> >> > > --- >> >> > > arch/x86/kernel/acpi/sleep.c | 3 +++ >> >> > > include/linux/kasan.h | 7 +++++++ >> >> > > 2 files changed, 10 insertions(+) >> >> > > >> >> > > diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c >> >> > > index 4858733..62bd046 100644 >> >> > > --- a/arch/x86/kernel/acpi/sleep.c >> >> > > +++ b/arch/x86/kernel/acpi/sleep.c >> >> > > @@ -115,6 +115,9 @@ int x86_acpi_suspend_lowlevel(void) >> >> > > pause_graph_tracing(); >> >> > > do_suspend_lowlevel(); >> >> > > unpause_graph_tracing(); >> >> > > + >> >> > > + kasan_unpoison_stack_below_sp(); >> >> > > + >> >> > >> >> > I think this might be too late. We may hit stale poison in the first C function called >> >> > after resume (restore_processor_state()). Thus the shadow must be unpoisoned prior such call, >> >> > i.e. somewhere in do_suspend_lowlevel() after .Lresume_point. >> >> >> >> Yeah, I think you're right. Will spin a v2. >> > >> > So I tried calling kasan_unpoison_task_stack_below() from >> > do_suspend_lowlevel(), but it hung on the resume. Presumably because >> > restore_processor_state() does some important setup which would be >> > needed before calling into kasan_unpoison_task_stack_below(). For >> > example, setting up the gs register. So it's a bit of a catch-22. >> > >> > It could probably be fixed properly by rewriting do_suspend_lowlevel() >> > to call restore_processor_state() with the temporary stack before >> > switching to the original stack and doing the unpoison. >> > >> > (And there are some other issues with do_suspend_lowlevel() and I'd love >> > to try taking a scalpel to it. But I have too many knives in the air >> > already to want to try to attempt that right now...) >> > >> > Unless somebody else wants to take a stab at it, my original patch is >> > probably good enough for now, since restore_processor_state() doesn't >> > seem to be triggering any KASAN warnings. >> >> restore_processor_state/__restore_processor_state does not seem to >> have any local variables, so KASAN does not do any stack checks there. > > Actually, looking at the object code, it uses a lot of stack space and > has several calls to __asan_report_load*() functions. Probably due to > inlining of other functions which have stack variables. That can be loads of heap variables (or other non-stack data). KASAN will emit these checks for lots of loads, but they don't necessary go to stack. >> We could disable KASAN instrumentation of the file, or of particular >> functions. > > I don't think that would be sufficient unless it were disabled for > __restore_processor_state() and all the functions it calls (and the > functions they call, etc), which wouldn't necessarily be > straightforward. > >> Or we could call kasan_unpoison_shadow() on the stack range >> before switching to it. > > I tried that already, but it hung because restore_processor_state() > hadn't been called yet (the catch-22 I mentioned aboved). Ah, I see, we just can't execute normal C code at that point...
[toc] | [prev] | [next] | [standalone]
| From | Josh Poimboeuf <jpoimboe@redhat.com> |
|---|---|
| Date | 2016-12-01 18:40 +0100 |
| Subject | Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume |
| Message-ID | <sJDuV-7nV-1@gated-at.bofh.it> |
| In reply to | #1534322 |
On Thu, Dec 01, 2016 at 06:27:31PM +0100, Dmitry Vyukov wrote: > On Thu, Dec 1, 2016 at 6:13 PM, Josh Poimboeuf <jpoimboe@redhat.com> wrote: > > On Thu, Dec 01, 2016 at 05:51:52PM +0100, Dmitry Vyukov wrote: > >> On Thu, Dec 1, 2016 at 5:45 PM, Josh Poimboeuf <jpoimboe@redhat.com> wrote: > >> > On Thu, Dec 01, 2016 at 08:58:21AM -0600, Josh Poimboeuf wrote: > >> >> On Thu, Dec 01, 2016 at 12:05:34PM +0300, Andrey Ryabinin wrote: > >> >> > > >> >> > > >> >> > On 12/01/2016 02:10 AM, Josh Poimboeuf wrote: > >> >> > > Resuming from a suspend operation is showing a KASAN false positive > >> >> > > warning: > >> >> > > > >> >> > > >> >> > > KASAN instrumentation poisons the stack when entering a function and > >> >> > > unpoisons it when exiting the function. However, in the suspend path, > >> >> > > some functions never return, so their stack never gets unpoisoned, > >> >> > > resulting in stale KASAN shadow data which can cause false positive > >> >> > > warnings like the one above. > >> >> > > > >> >> > > Reported-by: Scott Bauer <scott.bauer@intel.com> > >> >> > > Tested-by: Scott Bauer <scott.bauer@intel.com> > >> >> > > Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> > >> >> > > --- > >> >> > > arch/x86/kernel/acpi/sleep.c | 3 +++ > >> >> > > include/linux/kasan.h | 7 +++++++ > >> >> > > 2 files changed, 10 insertions(+) > >> >> > > > >> >> > > diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c > >> >> > > index 4858733..62bd046 100644 > >> >> > > --- a/arch/x86/kernel/acpi/sleep.c > >> >> > > +++ b/arch/x86/kernel/acpi/sleep.c > >> >> > > @@ -115,6 +115,9 @@ int x86_acpi_suspend_lowlevel(void) > >> >> > > pause_graph_tracing(); > >> >> > > do_suspend_lowlevel(); > >> >> > > unpause_graph_tracing(); > >> >> > > + > >> >> > > + kasan_unpoison_stack_below_sp(); > >> >> > > + > >> >> > > >> >> > I think this might be too late. We may hit stale poison in the first C function called > >> >> > after resume (restore_processor_state()). Thus the shadow must be unpoisoned prior such call, > >> >> > i.e. somewhere in do_suspend_lowlevel() after .Lresume_point. > >> >> > >> >> Yeah, I think you're right. Will spin a v2. > >> > > >> > So I tried calling kasan_unpoison_task_stack_below() from > >> > do_suspend_lowlevel(), but it hung on the resume. Presumably because > >> > restore_processor_state() does some important setup which would be > >> > needed before calling into kasan_unpoison_task_stack_below(). For > >> > example, setting up the gs register. So it's a bit of a catch-22. > >> > > >> > It could probably be fixed properly by rewriting do_suspend_lowlevel() > >> > to call restore_processor_state() with the temporary stack before > >> > switching to the original stack and doing the unpoison. > >> > > >> > (And there are some other issues with do_suspend_lowlevel() and I'd love > >> > to try taking a scalpel to it. But I have too many knives in the air > >> > already to want to try to attempt that right now...) > >> > > >> > Unless somebody else wants to take a stab at it, my original patch is > >> > probably good enough for now, since restore_processor_state() doesn't > >> > seem to be triggering any KASAN warnings. > >> > >> restore_processor_state/__restore_processor_state does not seem to > >> have any local variables, so KASAN does not do any stack checks there. > > > > Actually, looking at the object code, it uses a lot of stack space and > > has several calls to __asan_report_load*() functions. Probably due to > > inlining of other functions which have stack variables. > > That can be loads of heap variables (or other non-stack data). KASAN > will emit these checks for lots of loads, but they don't necessary go > to stack. I also see the stack poisoning instructions: 54f: 49 c1 ee 03 shr $0x3,%r14 553: 4c 01 f0 add %r14,%rax 556: c7 00 f1 f1 f1 f1 movl $0xf1f1f1f1,(%rax) 55c: c7 40 04 00 00 f4 f4 movl $0xf4f40000,0x4(%rax) 563: c7 40 08 f3 f3 f3 f3 movl $0xf3f3f3f3,0x8(%rax) > >> We could disable KASAN instrumentation of the file, or of particular > >> functions. > > > > I don't think that would be sufficient unless it were disabled for > > __restore_processor_state() and all the functions it calls (and the > > functions they call, etc), which wouldn't necessarily be > > straightforward. > > > >> Or we could call kasan_unpoison_shadow() on the stack range > >> before switching to it. > > > > I tried that already, but it hung because restore_processor_state() > > hadn't been called yet (the catch-22 I mentioned aboved). > > Ah, I see, we just can't execute normal C code at that point... Right. -- Josh
[toc] | [prev] | [next] | [standalone]
| From | Dmitry Vyukov <dvyukov@google.com> |
|---|---|
| Date | 2016-12-01 18:50 +0100 |
| Subject | Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume |
| Message-ID | <sJDEB-7vD-13@gated-at.bofh.it> |
| In reply to | #1534327 |
On Thu, Dec 1, 2016 at 6:34 PM, Josh Poimboeuf <jpoimboe@redhat.com> wrote: >> >> >> > >> >> >> > On 12/01/2016 02:10 AM, Josh Poimboeuf wrote: >> >> >> > > Resuming from a suspend operation is showing a KASAN false positive >> >> >> > > warning: >> >> >> > > >> >> >> > >> >> >> > > KASAN instrumentation poisons the stack when entering a function and >> >> >> > > unpoisons it when exiting the function. However, in the suspend path, >> >> >> > > some functions never return, so their stack never gets unpoisoned, >> >> >> > > resulting in stale KASAN shadow data which can cause false positive >> >> >> > > warnings like the one above. >> >> >> > > >> >> >> > > Reported-by: Scott Bauer <scott.bauer@intel.com> >> >> >> > > Tested-by: Scott Bauer <scott.bauer@intel.com> >> >> >> > > Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> >> >> >> > > --- >> >> >> > > arch/x86/kernel/acpi/sleep.c | 3 +++ >> >> >> > > include/linux/kasan.h | 7 +++++++ >> >> >> > > 2 files changed, 10 insertions(+) >> >> >> > > >> >> >> > > diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c >> >> >> > > index 4858733..62bd046 100644 >> >> >> > > --- a/arch/x86/kernel/acpi/sleep.c >> >> >> > > +++ b/arch/x86/kernel/acpi/sleep.c >> >> >> > > @@ -115,6 +115,9 @@ int x86_acpi_suspend_lowlevel(void) >> >> >> > > pause_graph_tracing(); >> >> >> > > do_suspend_lowlevel(); >> >> >> > > unpause_graph_tracing(); >> >> >> > > + >> >> >> > > + kasan_unpoison_stack_below_sp(); >> >> >> > > + >> >> >> > >> >> >> > I think this might be too late. We may hit stale poison in the first C function called >> >> >> > after resume (restore_processor_state()). Thus the shadow must be unpoisoned prior such call, >> >> >> > i.e. somewhere in do_suspend_lowlevel() after .Lresume_point. >> >> >> >> >> >> Yeah, I think you're right. Will spin a v2. >> >> > >> >> > So I tried calling kasan_unpoison_task_stack_below() from >> >> > do_suspend_lowlevel(), but it hung on the resume. Presumably because >> >> > restore_processor_state() does some important setup which would be >> >> > needed before calling into kasan_unpoison_task_stack_below(). For >> >> > example, setting up the gs register. So it's a bit of a catch-22. >> >> > >> >> > It could probably be fixed properly by rewriting do_suspend_lowlevel() >> >> > to call restore_processor_state() with the temporary stack before >> >> > switching to the original stack and doing the unpoison. >> >> > >> >> > (And there are some other issues with do_suspend_lowlevel() and I'd love >> >> > to try taking a scalpel to it. But I have too many knives in the air >> >> > already to want to try to attempt that right now...) >> >> > >> >> > Unless somebody else wants to take a stab at it, my original patch is >> >> > probably good enough for now, since restore_processor_state() doesn't >> >> > seem to be triggering any KASAN warnings. >> >> >> >> restore_processor_state/__restore_processor_state does not seem to >> >> have any local variables, so KASAN does not do any stack checks there. >> > >> > Actually, looking at the object code, it uses a lot of stack space and >> > has several calls to __asan_report_load*() functions. Probably due to >> > inlining of other functions which have stack variables. >> >> That can be loads of heap variables (or other non-stack data). KASAN >> will emit these checks for lots of loads, but they don't necessary go >> to stack. > > I also see the stack poisoning instructions: > > 54f: 49 c1 ee 03 shr $0x3,%r14 > 553: 4c 01 f0 add %r14,%rax > 556: c7 00 f1 f1 f1 f1 movl $0xf1f1f1f1,(%rax) > 55c: c7 40 04 00 00 f4 f4 movl $0xf4f40000,0x4(%rax) > 563: c7 40 08 f3 f3 f3 f3 movl $0xf3f3f3f3,0x8(%rax) OK, then we are in trouble potentially. It may work as long as as the stack region that is used for local vars in restore_processor_state() does not contain any stale poisoning. But it can break at any moment. Have you tried kasan_unpoison_task_stack_below() or kasan_unpoison_shadow()? I can see how kasan_unpoison_task_stack_below() can hang (it at least uses current). But kasan_unpoison_shadow() is quite trivial, it computes shadow address with simple math and writes zeroes there. >> >> We could disable KASAN instrumentation of the file, or of particular >> >> functions. >> > >> > I don't think that would be sufficient unless it were disabled for >> > __restore_processor_state() and all the functions it calls (and the >> > functions they call, etc), which wouldn't necessarily be >> > straightforward. >> > >> >> Or we could call kasan_unpoison_shadow() on the stack range >> >> before switching to it. >> > >> > I tried that already, but it hung because restore_processor_state() >> > hadn't been called yet (the catch-22 I mentioned aboved). >> >> Ah, I see, we just can't execute normal C code at that point... > > Right. > > -- > Josh > > -- > You received this message because you are subscribed to the Google Groups "kasan-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an email to kasan-dev+unsubscribe@googlegroups.com. > To post to this group, send email to kasan-dev@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/kasan-dev/20161201173438.bfe5eq23i6ezfxsq%40treble. > For more options, visit https://groups.google.com/d/optout.
[toc] | [prev] | [next] | [standalone]
| From | Josh Poimboeuf <jpoimboe@redhat.com> |
|---|---|
| Date | 2016-12-01 19:00 +0100 |
| Subject | Re: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume |
| Message-ID | <sJDOi-7Cs-9@gated-at.bofh.it> |
| In reply to | #1534338 |
On Thu, Dec 01, 2016 at 06:47:07PM +0100, Dmitry Vyukov wrote: > On Thu, Dec 1, 2016 at 6:34 PM, Josh Poimboeuf <jpoimboe@redhat.com> wrote: > >> >> >> > > >> >> >> > On 12/01/2016 02:10 AM, Josh Poimboeuf wrote: > >> >> >> > > Resuming from a suspend operation is showing a KASAN false positive > >> >> >> > > warning: > >> >> >> > > > >> >> >> > > >> >> >> > > KASAN instrumentation poisons the stack when entering a function and > >> >> >> > > unpoisons it when exiting the function. However, in the suspend path, > >> >> >> > > some functions never return, so their stack never gets unpoisoned, > >> >> >> > > resulting in stale KASAN shadow data which can cause false positive > >> >> >> > > warnings like the one above. > >> >> >> > > > >> >> >> > > Reported-by: Scott Bauer <scott.bauer@intel.com> > >> >> >> > > Tested-by: Scott Bauer <scott.bauer@intel.com> > >> >> >> > > Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> > >> >> >> > > --- > >> >> >> > > arch/x86/kernel/acpi/sleep.c | 3 +++ > >> >> >> > > include/linux/kasan.h | 7 +++++++ > >> >> >> > > 2 files changed, 10 insertions(+) > >> >> >> > > > >> >> >> > > diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c > >> >> >> > > index 4858733..62bd046 100644 > >> >> >> > > --- a/arch/x86/kernel/acpi/sleep.c > >> >> >> > > +++ b/arch/x86/kernel/acpi/sleep.c > >> >> >> > > @@ -115,6 +115,9 @@ int x86_acpi_suspend_lowlevel(void) > >> >> >> > > pause_graph_tracing(); > >> >> >> > > do_suspend_lowlevel(); > >> >> >> > > unpause_graph_tracing(); > >> >> >> > > + > >> >> >> > > + kasan_unpoison_stack_below_sp(); > >> >> >> > > + > >> >> >> > > >> >> >> > I think this might be too late. We may hit stale poison in the first C function called > >> >> >> > after resume (restore_processor_state()). Thus the shadow must be unpoisoned prior such call, > >> >> >> > i.e. somewhere in do_suspend_lowlevel() after .Lresume_point. > >> >> >> > >> >> >> Yeah, I think you're right. Will spin a v2. > >> >> > > >> >> > So I tried calling kasan_unpoison_task_stack_below() from > >> >> > do_suspend_lowlevel(), but it hung on the resume. Presumably because > >> >> > restore_processor_state() does some important setup which would be > >> >> > needed before calling into kasan_unpoison_task_stack_below(). For > >> >> > example, setting up the gs register. So it's a bit of a catch-22. > >> >> > > >> >> > It could probably be fixed properly by rewriting do_suspend_lowlevel() > >> >> > to call restore_processor_state() with the temporary stack before > >> >> > switching to the original stack and doing the unpoison. > >> >> > > >> >> > (And there are some other issues with do_suspend_lowlevel() and I'd love > >> >> > to try taking a scalpel to it. But I have too many knives in the air > >> >> > already to want to try to attempt that right now...) > >> >> > > >> >> > Unless somebody else wants to take a stab at it, my original patch is > >> >> > probably good enough for now, since restore_processor_state() doesn't > >> >> > seem to be triggering any KASAN warnings. > >> >> > >> >> restore_processor_state/__restore_processor_state does not seem to > >> >> have any local variables, so KASAN does not do any stack checks there. > >> > > >> > Actually, looking at the object code, it uses a lot of stack space and > >> > has several calls to __asan_report_load*() functions. Probably due to > >> > inlining of other functions which have stack variables. > >> > >> That can be loads of heap variables (or other non-stack data). KASAN > >> will emit these checks for lots of loads, but they don't necessary go > >> to stack. > > > > I also see the stack poisoning instructions: > > > > 54f: 49 c1 ee 03 shr $0x3,%r14 > > 553: 4c 01 f0 add %r14,%rax > > 556: c7 00 f1 f1 f1 f1 movl $0xf1f1f1f1,(%rax) > > 55c: c7 40 04 00 00 f4 f4 movl $0xf4f40000,0x4(%rax) > > 563: c7 40 08 f3 f3 f3 f3 movl $0xf3f3f3f3,0x8(%rax) > > OK, then we are in trouble potentially. > It may work as long as as the stack region that is used for local vars > in restore_processor_state() does not contain any stale poisoning. But > it can break at any moment. > > Have you tried kasan_unpoison_task_stack_below() or kasan_unpoison_shadow()? > I can see how kasan_unpoison_task_stack_below() can hang (it at least > uses current). But kasan_unpoison_shadow() is quite trivial, it > computes shadow address with simple math and writes zeroes there. Good idea, I'll give kasan_unpoison_shadow() a shot. -- Josh
[toc] | [prev] | [next] | [standalone]
| From | Josh Poimboeuf <jpoimboe@redhat.com> |
|---|---|
| Date | 2016-12-01 21:40 +0100 |
| Subject | [PATCH v2] x86/suspend: fix false positive KASAN warning on suspend/resume |
| Message-ID | <sJGj7-1KM-3@gated-at.bofh.it> |
| In reply to | #1534342 |
Resuming from a suspend operation is showing a KASAN false positive
warning:
BUG: KASAN: stack-out-of-bounds in unwind_get_return_address+0x11d/0x130 at addr ffff8803867d7878
Read of size 8 by task pm-suspend/7774
page:ffffea000e19f5c0 count:0 mapcount:0 mapping: (null) index:0x0
flags: 0x2ffff0000000000()
page dumped because: kasan: bad access detected
CPU: 0 PID: 7774 Comm: pm-suspend Tainted: G B 4.9.0-rc7+ #8
Hardware name: Gigabyte Technology Co., Ltd. Z170X-UD5/Z170X-UD5-CF, BIOS F5 03/07/2016
Call Trace:
dump_stack+0x63/0x82
kasan_report_error+0x4b4/0x4e0
? acpi_hw_read_port+0xd0/0x1ea
? kfree_const+0x22/0x30
? acpi_hw_validate_io_request+0x1a6/0x1a6
__asan_report_load8_noabort+0x61/0x70
? unwind_get_return_address+0x11d/0x130
unwind_get_return_address+0x11d/0x130
? unwind_next_frame+0x97/0xf0
__save_stack_trace+0x92/0x100
save_stack_trace+0x1b/0x20
save_stack+0x46/0xd0
? save_stack_trace+0x1b/0x20
? save_stack+0x46/0xd0
? kasan_kmalloc+0xad/0xe0
? kasan_slab_alloc+0x12/0x20
? acpi_hw_read+0x2b6/0x3aa
? acpi_hw_validate_register+0x20b/0x20b
? acpi_hw_write_port+0x72/0xc7
? acpi_hw_write+0x11f/0x15f
? acpi_hw_read_multiple+0x19f/0x19f
? memcpy+0x45/0x50
? acpi_hw_write_port+0x72/0xc7
? acpi_hw_write+0x11f/0x15f
? acpi_hw_read_multiple+0x19f/0x19f
? kasan_unpoison_shadow+0x36/0x50
kasan_kmalloc+0xad/0xe0
kasan_slab_alloc+0x12/0x20
kmem_cache_alloc_trace+0xbc/0x1e0
? acpi_get_sleep_type_data+0x9a/0x578
acpi_get_sleep_type_data+0x9a/0x578
acpi_hw_legacy_wake_prep+0x88/0x22c
? acpi_hw_legacy_sleep+0x3c7/0x3c7
? acpi_write_bit_register+0x28d/0x2d3
? acpi_read_bit_register+0x19b/0x19b
acpi_hw_sleep_dispatch+0xb5/0xba
acpi_leave_sleep_state_prep+0x17/0x19
acpi_suspend_enter+0x154/0x1e0
? trace_suspend_resume+0xe8/0xe8
suspend_devices_and_enter+0xb09/0xdb0
? printk+0xa8/0xd8
? arch_suspend_enable_irqs+0x20/0x20
? try_to_freeze_tasks+0x295/0x600
pm_suspend+0x6c9/0x780
? finish_wait+0x1f0/0x1f0
? suspend_devices_and_enter+0xdb0/0xdb0
state_store+0xa2/0x120
? kobj_attr_show+0x60/0x60
kobj_attr_store+0x36/0x70
sysfs_kf_write+0x131/0x200
kernfs_fop_write+0x295/0x3f0
__vfs_write+0xef/0x760
? handle_mm_fault+0x1346/0x35e0
? do_iter_readv_writev+0x660/0x660
? __pmd_alloc+0x310/0x310
? do_lock_file_wait+0x1e0/0x1e0
? apparmor_file_permission+0x18/0x20
? security_file_permission+0x73/0x1c0
? rw_verify_area+0xbd/0x2b0
vfs_write+0x149/0x4a0
SyS_write+0xd9/0x1c0
? SyS_read+0x1c0/0x1c0
entry_SYSCALL_64_fastpath+0x1e/0xad
Memory state around the buggy address:
ffff8803867d7700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8803867d7780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8803867d7800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f4
^
ffff8803867d7880: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
ffff8803867d7900: 00 00 00 f1 f1 f1 f1 04 f4 f4 f4 f3 f3 f3 f3 00
KASAN instrumentation poisons the stack when entering a function and
unpoisons it when exiting the function. However, in the suspend path,
some functions never return, so their stack never gets unpoisoned,
resulting in stale KASAN shadow data which can cause later false
positive warnings like the one above.
Reported-by: Scott Bauer <scott.bauer@intel.com>
Suggested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
arch/x86/kernel/acpi/wakeup_64.S | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/arch/x86/kernel/acpi/wakeup_64.S b/arch/x86/kernel/acpi/wakeup_64.S
index 169963f..1df9b75 100644
--- a/arch/x86/kernel/acpi/wakeup_64.S
+++ b/arch/x86/kernel/acpi/wakeup_64.S
@@ -109,6 +109,22 @@ ENTRY(do_suspend_lowlevel)
movq pt_regs_r14(%rax), %r14
movq pt_regs_r15(%rax), %r15
+#ifdef CONFIG_KASAN
+ /*
+ * The suspend path may have poisoned some areas deeper in the stack,
+ * which we now need to unpoison.
+ *
+ * We can't call kasan_unpoison_task_stack_below() because it uses %gs
+ * for 'current', which hasn't been set up yet. Instead, calculate the
+ * stack range manually and call kasan_unpoison_shadow().
+ */
+ movq %rsp, %rdi
+ andq $CURRENT_MASK, %rdi
+ movq %rsp, %rsi
+ xorq %rdi, %rsi
+ call kasan_unpoison_shadow
+#endif
+
xorl %eax, %eax
addq $8, %rsp
FRAME_END
--
2.7.4
[toc] | [prev] | [next] | [standalone]
| From | Dmitry Vyukov <dvyukov@google.com> |
|---|---|
| Date | 2016-12-02 10:50 +0100 |
| Subject | Re: [PATCH v2] x86/suspend: fix false positive KASAN warning on suspend/resume |
| Message-ID | <sJSDD-26e-19@gated-at.bofh.it> |
| In reply to | #1534425 |
On Thu, Dec 1, 2016 at 9:31 PM, Josh Poimboeuf <jpoimboe@redhat.com> wrote: > Resuming from a suspend operation is showing a KASAN false positive > warning: > > BUG: KASAN: stack-out-of-bounds in unwind_get_return_address+0x11d/0x130 at addr ffff8803867d7878 > Read of size 8 by task pm-suspend/7774 > page:ffffea000e19f5c0 count:0 mapcount:0 mapping: (null) index:0x0 > flags: 0x2ffff0000000000() > page dumped because: kasan: bad access detected > CPU: 0 PID: 7774 Comm: pm-suspend Tainted: G B 4.9.0-rc7+ #8 > Hardware name: Gigabyte Technology Co., Ltd. Z170X-UD5/Z170X-UD5-CF, BIOS F5 03/07/2016 > Call Trace: > dump_stack+0x63/0x82 > kasan_report_error+0x4b4/0x4e0 > ? acpi_hw_read_port+0xd0/0x1ea > ? kfree_const+0x22/0x30 > ? acpi_hw_validate_io_request+0x1a6/0x1a6 > __asan_report_load8_noabort+0x61/0x70 > ? unwind_get_return_address+0x11d/0x130 > unwind_get_return_address+0x11d/0x130 > ? unwind_next_frame+0x97/0xf0 > __save_stack_trace+0x92/0x100 > save_stack_trace+0x1b/0x20 > save_stack+0x46/0xd0 > ? save_stack_trace+0x1b/0x20 > ? save_stack+0x46/0xd0 > ? kasan_kmalloc+0xad/0xe0 > ? kasan_slab_alloc+0x12/0x20 > ? acpi_hw_read+0x2b6/0x3aa > ? acpi_hw_validate_register+0x20b/0x20b > ? acpi_hw_write_port+0x72/0xc7 > ? acpi_hw_write+0x11f/0x15f > ? acpi_hw_read_multiple+0x19f/0x19f > ? memcpy+0x45/0x50 > ? acpi_hw_write_port+0x72/0xc7 > ? acpi_hw_write+0x11f/0x15f > ? acpi_hw_read_multiple+0x19f/0x19f > ? kasan_unpoison_shadow+0x36/0x50 > kasan_kmalloc+0xad/0xe0 > kasan_slab_alloc+0x12/0x20 > kmem_cache_alloc_trace+0xbc/0x1e0 > ? acpi_get_sleep_type_data+0x9a/0x578 > acpi_get_sleep_type_data+0x9a/0x578 > acpi_hw_legacy_wake_prep+0x88/0x22c > ? acpi_hw_legacy_sleep+0x3c7/0x3c7 > ? acpi_write_bit_register+0x28d/0x2d3 > ? acpi_read_bit_register+0x19b/0x19b > acpi_hw_sleep_dispatch+0xb5/0xba > acpi_leave_sleep_state_prep+0x17/0x19 > acpi_suspend_enter+0x154/0x1e0 > ? trace_suspend_resume+0xe8/0xe8 > suspend_devices_and_enter+0xb09/0xdb0 > ? printk+0xa8/0xd8 > ? arch_suspend_enable_irqs+0x20/0x20 > ? try_to_freeze_tasks+0x295/0x600 > pm_suspend+0x6c9/0x780 > ? finish_wait+0x1f0/0x1f0 > ? suspend_devices_and_enter+0xdb0/0xdb0 > state_store+0xa2/0x120 > ? kobj_attr_show+0x60/0x60 > kobj_attr_store+0x36/0x70 > sysfs_kf_write+0x131/0x200 > kernfs_fop_write+0x295/0x3f0 > __vfs_write+0xef/0x760 > ? handle_mm_fault+0x1346/0x35e0 > ? do_iter_readv_writev+0x660/0x660 > ? __pmd_alloc+0x310/0x310 > ? do_lock_file_wait+0x1e0/0x1e0 > ? apparmor_file_permission+0x18/0x20 > ? security_file_permission+0x73/0x1c0 > ? rw_verify_area+0xbd/0x2b0 > vfs_write+0x149/0x4a0 > SyS_write+0xd9/0x1c0 > ? SyS_read+0x1c0/0x1c0 > entry_SYSCALL_64_fastpath+0x1e/0xad > Memory state around the buggy address: > ffff8803867d7700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ffff8803867d7780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > >ffff8803867d7800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f4 > ^ > ffff8803867d7880: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 > ffff8803867d7900: 00 00 00 f1 f1 f1 f1 04 f4 f4 f4 f3 f3 f3 f3 00 > > KASAN instrumentation poisons the stack when entering a function and > unpoisons it when exiting the function. However, in the suspend path, > some functions never return, so their stack never gets unpoisoned, > resulting in stale KASAN shadow data which can cause later false > positive warnings like the one above. > > Reported-by: Scott Bauer <scott.bauer@intel.com> > Suggested-by: Dmitry Vyukov <dvyukov@google.com> > Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> > --- > arch/x86/kernel/acpi/wakeup_64.S | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/arch/x86/kernel/acpi/wakeup_64.S b/arch/x86/kernel/acpi/wakeup_64.S > index 169963f..1df9b75 100644 > --- a/arch/x86/kernel/acpi/wakeup_64.S > +++ b/arch/x86/kernel/acpi/wakeup_64.S > @@ -109,6 +109,22 @@ ENTRY(do_suspend_lowlevel) > movq pt_regs_r14(%rax), %r14 > movq pt_regs_r15(%rax), %r15 > > +#ifdef CONFIG_KASAN > + /* > + * The suspend path may have poisoned some areas deeper in the stack, > + * which we now need to unpoison. > + * > + * We can't call kasan_unpoison_task_stack_below() because it uses %gs > + * for 'current', which hasn't been set up yet. Instead, calculate the > + * stack range manually and call kasan_unpoison_shadow(). > + */ > + movq %rsp, %rdi > + andq $CURRENT_MASK, %rdi > + movq %rsp, %rsi > + xorq %rdi, %rsi > + call kasan_unpoison_shadow > +#endif > + > xorl %eax, %eax > addq $8, %rsp > FRAME_END Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Thanks!
[toc] | [prev] | [next] | [standalone]
| From | Pavel Machek <pavel@ucw.cz> |
|---|---|
| Date | 2016-12-02 14:00 +0100 |
| Subject | Re: [PATCH v2] x86/suspend: fix false positive KASAN warning on suspend/resume |
| Message-ID | <sJVBw-3XH-27@gated-at.bofh.it> |
| In reply to | #1534425 |
[Multipart message — attachments visible in raw view] — view raw
Hi! > Resuming from a suspend operation is showing a KASAN false positive > warning: > KASAN instrumentation poisons the stack when entering a function and > unpoisons it when exiting the function. However, in the suspend path, > some functions never return, so their stack never gets unpoisoned, > resulting in stale KASAN shadow data which can cause later false > positive warnings like the one above. > > Reported-by: Scott Bauer <scott.bauer@intel.com> > Suggested-by: Dmitry Vyukov <dvyukov@google.com> > Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Pavel Machek <pavel@ucw.cz> > --- > arch/x86/kernel/acpi/wakeup_64.S | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/arch/x86/kernel/acpi/wakeup_64.S b/arch/x86/kernel/acpi/wakeup_64.S > index 169963f..1df9b75 100644 > --- a/arch/x86/kernel/acpi/wakeup_64.S > +++ b/arch/x86/kernel/acpi/wakeup_64.S > @@ -109,6 +109,22 @@ ENTRY(do_suspend_lowlevel) > movq pt_regs_r14(%rax), %r14 > movq pt_regs_r15(%rax), %r15 > > +#ifdef CONFIG_KASAN > + /* > + * The suspend path may have poisoned some areas deeper in the stack, > + * which we now need to unpoison. > + * > + * We can't call kasan_unpoison_task_stack_below() because it uses %gs > + * for 'current', which hasn't been set up yet. Instead, calculate the > + * stack range manually and call kasan_unpoison_shadow(). > + */ > + movq %rsp, %rdi > + andq $CURRENT_MASK, %rdi > + movq %rsp, %rsi > + xorq %rdi, %rsi > + call kasan_unpoison_shadow > +#endif Well... you may want to add note to kasan_unpoison_shadow() /* * This is called by early resume code, with cpu not yer properly * resumed. In particular, %gs may not be set up, and thus current * is not available. */ Thanks, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
[toc] | [prev] | [next] | [standalone]
| From | Dmitry Vyukov <dvyukov@google.com> |
|---|---|
| Date | 2016-12-02 15:10 +0100 |
| Subject | Re: [PATCH v2] x86/suspend: fix false positive KASAN warning on suspend/resume |
| Message-ID | <sJWHg-4R5-37@gated-at.bofh.it> |
| In reply to | #1534425 |
On Fri, Dec 2, 2016 at 3:01 PM, Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> On Fri, Dec 02, 2016 at 04:41:09PM +0300, Andrey Ryabinin wrote:
>>
>>
>> On 12/01/2016 11:31 PM, Josh Poimboeuf wrote:
>>
>> > arch/x86/kernel/acpi/wakeup_64.S | 16 ++++++++++++++++
>> > 1 file changed, 16 insertions(+)
>> >
>> > diff --git a/arch/x86/kernel/acpi/wakeup_64.S b/arch/x86/kernel/acpi/wakeup_64.S
>> > index 169963f..1df9b75 100644
>> > --- a/arch/x86/kernel/acpi/wakeup_64.S
>> > +++ b/arch/x86/kernel/acpi/wakeup_64.S
>> > @@ -109,6 +109,22 @@ ENTRY(do_suspend_lowlevel)
>> > movq pt_regs_r14(%rax), %r14
>> > movq pt_regs_r15(%rax), %r15
>> >
>> > +#ifdef CONFIG_KASAN
>> > + /*
>> > + * The suspend path may have poisoned some areas deeper in the stack,
>> > + * which we now need to unpoison.
>> > + *
>> > + * We can't call kasan_unpoison_task_stack_below() because it uses %gs
>> > + * for 'current', which hasn't been set up yet. Instead, calculate the
>> > + * stack range manually and call kasan_unpoison_shadow().
>> > + */
>> > + movq %rsp, %rdi
>> > + andq $CURRENT_MASK, %rdi
>> > + movq %rsp, %rsi
>> > + xorq %rdi, %rsi
>> > + call kasan_unpoison_shadow
>> > +#endif
>> > +
>>
>> Looks good, but in fact we can use kasan_unpoison_task_stack_below(). We just need to change it a little:
>>
>> diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
>> index 70c0097..e779236 100644
>> --- a/mm/kasan/kasan.c
>> +++ b/mm/kasan/kasan.c
>> @@ -80,7 +80,9 @@ void kasan_unpoison_task_stack(struct task_struct *task)
>> /* Unpoison the stack for the current task beyond a watermark sp value. */
>> asmlinkage void kasan_unpoison_task_stack_below(const void *watermark)
>> {
>> - __kasan_unpoison_stack(current, watermark);
>> + void *base = (void *)((unsigned long)watermark & ~(THREAD_SIZE - 1));
>> +
>> + kasan_unpoison_shadow(base, watermark - base);
>> }
>>
>>
>> With this we don't have to calculate stack range in assembly.
>
> That is better indeed, will do a v3.
agree
[toc] | [prev] | [next] | [standalone]
Page 1 of 2 [1] 2 Next page →
Back to top | Article view | linux.kernel
csiph-web