Groups > linux.kernel > #1202056

[PATCH 3.13.y-ckt 39/53] ARC: make sure instruction_pointer() returns unsigned value

From	Kamal Mostafa <kamal@canonical.com>
Newsgroups	linux.kernel
Subject	[PATCH 3.13.y-ckt 39/53] ARC: make sure instruction_pointer() returns unsigned value
Date	2015-08-06 22:50 +0200
Message-ID	<pUAgZ-3gz-73@gated-at.bofh.it> (permalink)
References	<pUA7f-34H-5@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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3.13.11-ckt25 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alexey Brodkin <abrodkin@synopsys.com>

commit f51e2f1911122879eefefa4c592dea8bf794b39c upstream.

Currently instruction_pointer() returns pt_regs->ret and so return value
is of type "long", which implicitly stands for "signed long".

While that's perfectly fine when dealing with 32-bit values if return
value of instruction_pointer() gets assigned to 64-bit variable sign
extension may happen.

And at least in one real use-case it happens already.
In perf_prepare_sample() return value of perf_instruction_pointer()
(which is an alias to instruction_pointer() in case of ARC) is assigned
to (struct perf_sample_data)->ip (which type is "u64").

And what we see if instuction pointer points to user-space application
that in case of ARC lays below 0x8000_0000 "ip" gets set properly with
leading 32 zeros. But if instruction pointer points to kernel address
space that starts from 0x8000_0000 then "ip" is set with 32 leadig
"f"-s. I.e. id instruction_pointer() returns 0x8100_0000, "ip" will be
assigned with 0xffff_ffff__8100_0000. Which is obviously wrong.

In particular that issuse broke output of perf, because perf was unable
to associate addresses like 0xffff_ffff__8100_0000 with anything from
/proc/kallsyms.

That's what we used to see:
 ----------->8----------
  6.27%  ls       [unknown]                [k] 0xffffffff8046c5cc
  2.96%  ls       libuClibc-0.9.34-git.so  [.] memcpy
  2.25%  ls       libuClibc-0.9.34-git.so  [.] memset
  1.66%  ls       [unknown]                [k] 0xffffffff80666536
  1.54%  ls       libuClibc-0.9.34-git.so  [.] 0x000224d6
  1.18%  ls       libuClibc-0.9.34-git.so  [.] 0x00022472
 ----------->8----------

With that change perf output looks much better now:
 ----------->8----------
  8.21%  ls       [kernel.kallsyms]        [k] memset
  3.52%  ls       libuClibc-0.9.34-git.so  [.] memcpy
  2.11%  ls       libuClibc-0.9.34-git.so  [.] malloc
  1.88%  ls       libuClibc-0.9.34-git.so  [.] memset
  1.64%  ls       [kernel.kallsyms]        [k] _raw_spin_unlock_irqrestore
  1.41%  ls       [kernel.kallsyms]        [k] __d_lookup_rcu
 ----------->8----------

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: arc-linux-dev@synopsys.com
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 arch/arc/include/asm/ptrace.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arc/include/asm/ptrace.h b/arch/arc/include/asm/ptrace.h
index 1bfeec2..2a58af7 100644
--- a/arch/arc/include/asm/ptrace.h
+++ b/arch/arc/include/asm/ptrace.h
@@ -63,7 +63,7 @@ struct callee_regs {
 	long r25, r24, r23, r22, r21, r20, r19, r18, r17, r16, r15, r14, r13;
 };
 
-#define instruction_pointer(regs)	((regs)->ret)
+#define instruction_pointer(regs)	(unsigned long)((regs)->ret)
 #define profile_pc(regs)		instruction_pointer(regs)
 
 /* return 1 if user mode or 0 if kernel mode */
-- 
1.9.1

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Thread

[3.13.y-ckt stable] Linux 3.13.11-ckt25 stable review Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:40 +0200
  [PATCH 3.13.y-ckt 37/53] USB: serial: Destroy serial_minors IDR on module exit Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 44/53] genirq: Prevent resend to interrupts marked IRQ_NESTED_THREAD Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 01/53] x86/asm/entry/64: Fold the 'test_in_nmi' macro into its only user Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 47/53] bridge: mdb: zero out the local br_ip variable before use Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 49/53] net: graceful exit from netif_alloc_netdev_queues() Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 45/53] ip_tunnel: fix ipv4 pmtu check to honor inner ip header df Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 24/53] iio: adc: at91_adc: allow to use full range of startup time Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 29/53] USB: cp210x: add ID for Aruba Networks controllers Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 28/53] USB: option: add 2020:4000 ID Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 11/53] Btrfs: use kmem_cache_free when freeing entry in inode cache Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 50/53] net: dsa: Fix off-by-one in switch address parsing Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 10/53] sg_start_req(): make sure that there's not too many elements in iovec Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 25/53] ALSA: usb-audio: Add MIDI support for Steinberg MI2/MI4 Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 38/53] Btrfs: fix memory leak in the extent_same ioctl Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 13/53] Btrfs: fix fsync data loss after append write Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 19/53] hpfs: kstrdup() out of memory handling Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 34/53] ARM: dts: mx23: fix iio-hwmon support Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 46/53] bridge: mdb: start delete timer for temp static entries Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 41/53] st: null pointer dereference panic caused by use after kref_put by st_open Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 40/53] s390/process: fix sfpc inline assembly Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 33/53] drm: add a check for x/y in drm_mode_setcrtc Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 15/53] ext4: be more strict when migrating to non-extent based file Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 02/53] x86/asm/entry/64: Remove a redundant jump Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 35/53] tracing: Have branch tracer use recursive field of task struct Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 27/53] dm btree remove: fix bug in redistribute3 Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 32/53] s390/sclp: clear upper register halves in _sclp_print_early Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 30/53] dm btree: silence lockdep lock inversion in dm_btree_del() Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 26/53] iio: tmp006: Check channel info on write Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 36/53] drivers: net: cpsw: fix crash while accessing second slave ethernet interface Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 31/53] usb: musb: host: rely on port_mode to call musb_start() Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 22/53] iio: inv-mpu: Specify the expected format/precision for write channels Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 42/53] drm/radeon: add a dpm quirk for Sapphire Radeon R9 270X 2GB GDDR5 Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 39/53] ARC: make sure instruction_pointer() returns unsigned value Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 23/53] iio: DAC: ad5624r_spi: fix bit shift of output data value Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 14/53] ext4: fix reservation release on invalidatepage for delalloc fs Kamal Mostafa <kamal@canonical.com> - 2015-08-06 22:50 +0200
  [PATCH 3.13.y-ckt 07/53] x86/nmi/64: Reorder nested NMI checks Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200
  [PATCH 3.13.y-ckt 21/53] freeing unlinked file indefinitely delayed Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200
  [PATCH 3.13.y-ckt 08/53] x86/nmi/64: Use DF to avoid userspace RSP confusing nested NMI detection Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200
  [PATCH 3.13.y-ckt 16/53] ext4: correctly migrate a file with a hole at the beginning Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200
  [PATCH 3.13.y-ckt 06/53] x86/nmi/64: Improve nested NMI comments Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200
  [PATCH 3.13.y-ckt 05/53] x86/nmi/64: Switch stacks on userspace NMI entry Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200
  [PATCH 3.13.y-ckt 20/53] 9p: don't leave a half-initialized inode sitting around Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200
  [PATCH 3.13.y-ckt 12/53] Btrfs: fix race between caching kthread and returning inode to inode cache Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200
  [PATCH 3.13.y-ckt 03/53] x86/nmi: Enable nested do_nmi handling for 64-bit kernels Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200
  [PATCH 3.13.y-ckt 18/53] ACPI / PNP: Reserve ACPI resources at the fs_initcall_sync stage Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200
  [PATCH 3.13.y-ckt 17/53] ext4: replace open coded nofail allocation in ext4_free_blocks() Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200
  [PATCH 3.13.y-ckt 09/53] KEYS: ensure we free the assoc array edit if edit is valid Kamal Mostafa <kamal@canonical.com> - 2015-08-06 23:00 +0200

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