Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1635509
| From | Jiri Slaby <jslaby@suse.cz> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 3.12 82/86] MIPS: KGDB: Use kernel context for sleeping threads |
| Date | 2017-05-04 11:10 +0200 |
| Message-ID | <tDkVR-1oS-39@gated-at.bofh.it> (permalink) |
| References | <tDkVQ-1oS-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
From: James Hogan <james.hogan@imgtec.com>
3.12-stable review patch. If anyone has any objections, please let me know.
===============
commit 162b270c664dca2e0944308e92f9fcc887151a72 upstream.
KGDB is a kernel debug stub and it can't be used to debug userland as it
can only safely access kernel memory.
On MIPS however KGDB has always got the register state of sleeping
processes from the userland register context at the beginning of the
kernel stack. This is meaningless for kernel threads (which never enter
userland), and for user threads it prevents the user seeing what it is
doing while in the kernel:
(gdb) info threads
Id Target Id Frame
...
3 Thread 2 (kthreadd) 0x0000000000000000 in ?? ()
2 Thread 1 (init) 0x000000007705c4b4 in ?? ()
1 Thread -2 (shadowCPU0) 0xffffffff8012524c in arch_kgdb_breakpoint () at arch/mips/kernel/kgdb.c:201
Get the register state instead from the (partial) kernel register
context stored in the task's thread_struct for resume() to restore. All
threads now correctly appear to be in context_switch():
(gdb) info threads
Id Target Id Frame
...
3 Thread 2 (kthreadd) context_switch (rq=<optimized out>, cookie=..., next=<optimized out>, prev=0x0) at kernel/sched/core.c:2903
2 Thread 1 (init) context_switch (rq=<optimized out>, cookie=..., next=<optimized out>, prev=0x0) at kernel/sched/core.c:2903
1 Thread -2 (shadowCPU0) 0xffffffff8012524c in arch_kgdb_breakpoint () at arch/mips/kernel/kgdb.c:201
Call clobbered registers which aren't saved and exception registers
(BadVAddr & Cause) which can't be easily determined without stack
unwinding are reported as 0. The PC is taken from the return address,
such that the state presented matches that found immediately after
returning from resume().
Fixes: 8854700115ec ("[MIPS] kgdb: add arch support for the kernel's kgdb core")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/15829/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
arch/mips/kernel/kgdb.c | 48 +++++++++++++++++++++++++++++++++---------------
1 file changed, 33 insertions(+), 15 deletions(-)
diff --git a/arch/mips/kernel/kgdb.c b/arch/mips/kernel/kgdb.c
index fcaac2f132f0..910db386d9ef 100644
--- a/arch/mips/kernel/kgdb.c
+++ b/arch/mips/kernel/kgdb.c
@@ -236,9 +236,6 @@ static int compute_signal(int tt)
void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
{
int reg;
- struct thread_info *ti = task_thread_info(p);
- unsigned long ksp = (unsigned long)ti + THREAD_SIZE - 32;
- struct pt_regs *regs = (struct pt_regs *)ksp - 1;
#if (KGDB_GDB_REG_SIZE == 32)
u32 *ptr = (u32 *)gdb_regs;
#else
@@ -246,25 +243,46 @@ void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
#endif
for (reg = 0; reg < 16; reg++)
- *(ptr++) = regs->regs[reg];
+ *(ptr++) = 0;
/* S0 - S7 */
- for (reg = 16; reg < 24; reg++)
- *(ptr++) = regs->regs[reg];
+ *(ptr++) = p->thread.reg16;
+ *(ptr++) = p->thread.reg17;
+ *(ptr++) = p->thread.reg18;
+ *(ptr++) = p->thread.reg19;
+ *(ptr++) = p->thread.reg20;
+ *(ptr++) = p->thread.reg21;
+ *(ptr++) = p->thread.reg22;
+ *(ptr++) = p->thread.reg23;
for (reg = 24; reg < 28; reg++)
*(ptr++) = 0;
/* GP, SP, FP, RA */
- for (reg = 28; reg < 32; reg++)
- *(ptr++) = regs->regs[reg];
-
- *(ptr++) = regs->cp0_status;
- *(ptr++) = regs->lo;
- *(ptr++) = regs->hi;
- *(ptr++) = regs->cp0_badvaddr;
- *(ptr++) = regs->cp0_cause;
- *(ptr++) = regs->cp0_epc;
+ *(ptr++) = (long)p;
+ *(ptr++) = p->thread.reg29;
+ *(ptr++) = p->thread.reg30;
+ *(ptr++) = p->thread.reg31;
+
+ *(ptr++) = p->thread.cp0_status;
+
+ /* lo, hi */
+ *(ptr++) = 0;
+ *(ptr++) = 0;
+
+ /*
+ * BadVAddr, Cause
+ * Ideally these would come from the last exception frame up the stack
+ * but that requires unwinding, otherwise we can't know much for sure.
+ */
+ *(ptr++) = 0;
+ *(ptr++) = 0;
+
+ /*
+ * PC
+ * use return address (RA), i.e. the moment after return from resume()
+ */
+ *(ptr++) = p->thread.reg31;
}
void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
--
2.12.2
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
[PATCH 3.12 00/86] 3.12.74-stable review Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:10 +0200
[PATCH 3.12 01/86] drm/vmwgfx: NULL pointer dereference in vmw_surface_define_ioctl() Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:10 +0200
[PATCH 3.12 04/86] drm/vmwgfx: fix integer overflow in vmw_surface_define_ioctl() Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:10 +0200
[PATCH 3.12 81/86] ALSA: seq: Don't break snd_use_lock_sync() loop by timeout Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:10 +0200
[PATCH 3.12 25/86] perf/x86: Avoid exposing wrong/stale data in intel_pmu_lbr_read_32() Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:10 +0200
[PATCH 3.12 03/86] drm/vmwgfx: Remove getparam error message Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:10 +0200
[PATCH 3.12 05/86] Reset TreeId to zero on SMB2 TREE_CONNECT Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:10 +0200
[PATCH 3.12 85/86] nfsd: check for oversized NFSv2/v3 arguments Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:10 +0200
[PATCH 3.12 59/86] kvm: arm/arm64: Fix locking for kvm_free_stage2_pgd Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:10 +0200
[PATCH 3.12 26/86] x86/vdso: Plug race between mapping and ELF header setup Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:10 +0200
[PATCH 3.12 82/86] MIPS: KGDB: Use kernel context for sleeping threads Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:10 +0200
[PATCH 3.12 31/86] xen, fbfront: fix connecting to backend Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:10 +0200
[PATCH 3.12 56/86] ACPI / power: Avoid maybe-uninitialized warning Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:10 +0200
[PATCH 3.12 78/86] MIPS: Fix crash registers on non-crashing CPUs Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:10 +0200
[PATCH 3.12 28/86] iscsi-target: Drop work-around for legacy GlobalSAN initiator Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:10 +0200
[PATCH 3.12 29/86] scsi: sr: Sanity check returned mode data Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:10 +0200
[PATCH 3.12 83/86] p9_client_readdir() fix Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:10 +0200
[PATCH 3.12 06/86] ptrace: fix PTRACE_LISTEN race corrupting task->state Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:10 +0200
[PATCH 3.12 80/86] xen/x86: don't lose event interrupts Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:10 +0200
[PATCH 3.12 55/86] Input: elantech - add Fujitsu Lifebook E547 to force crc_enabled Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:10 +0200
[PATCH 3.12 77/86] md:raid1: fix a dead loop when read from a WriteMostly disk Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 63/86] net/packet: fix overflow in check for tp_frame_nr Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 72/86] net: ipv4: fix multipath RTM_GETROUTE behavior when iif is given Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 61/86] powerpc: Reject binutils 2.24 when building little endian Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 75/86] ipv6: check raw payload size correctly in ioctl Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 60/86] block: fix del_gendisk() vs blkdev_ioctl crash Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 33/86] char: lack of bool string made CONFIG_DEVPORT always on Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 74/86] ip6mr: fix notification device destruction Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 66/86] tty: nozomi: avoid a harmless gcc warning Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 67/86] hostap: avoid uninitialized variable use in hfa384x_get_rid Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 64/86] net/packet: fix overflow in check for tp_reserve Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 76/86] ext4: check if in-inode xattr is corrupted in ext4_expand_extra_isize_ea() Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 45/86] net: ipv6: check route protocol when deleting routes Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 46/86] KEYS: Disallow keyrings beginning with '.' to be joined as session keyrings Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 65/86] netfilter: arp_tables: fix invoking 32bit "iptable -P INPUT ACCEPT" failed in 64bit kernel Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 42/86] rtl8150: Use heap buffers for all register access Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 30/86] scsi: sd: Fix capacity calculation with 32-bit sector_t Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 39/86] mm: Tighten x86 /dev/mem with zeroing reads Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 43/86] catc: Combine failure cleanup code in catc_probe() Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 51/86] cifs: Do not send echoes before Negotiate is complete Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 40/86] virtio-console: avoid DMA from stack Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 69/86] net: neigh: guard against NULL solicit() method Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 49/86] tracing: Allocate the snapshot buffer before enabling probe Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 50/86] ring-buffer: Have ring_buffer_iter_empty() return true when empty Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 53/86] Drivers: hv: don't leak memory in vmbus_establish_gpadl() Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 62/86] ping: implement proper locking Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 79/86] RDS: Fix the atomicity for congestion map update Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 84/86] Input: i8042 - add Clevo P650RS to the i8042 reset list Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 52/86] CIFS: remove bad_network_name flag Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 54/86] Drivers: hv: get rid of timeout in vmbus_open() Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 47/86] KEYS: Change the name of the dead type to ".dead" to prevent user access Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 41/86] pegasus: Use heap buffers for all register access Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 37/86] ext4: fix inode checksum calculation problem if i_extra_size is small Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 38/86] platform/x86: acer-wmi: setup accelerometer when machine has appropriate notify event Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 71/86] l2tp: take reference on sessions being dumped Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 68/86] gfs2: avoid uninitialized variable warning Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 70/86] net: phy: handle state correctly in phy_stop_machine Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 58/86] x86/mce/AMD: Give a name to MCA bank 3 when accessed with legacy MSRs Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 73/86] sctp: listen on the sock only when it's state is listening or closed Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:20 +0200
[PATCH 3.12 18/86] usb: dwc3: gadget: delay unmap of bounced requests Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
[PATCH 3.12 32/86] char: Drop bogus dependency of DEVPORT on !M68K Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
[PATCH 3.12 36/86] dvb-usb-v2: avoid use-after-free Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
[PATCH 3.12 14/86] metag/usercopy: Add missing fixups Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
[PATCH 3.12 10/86] metag/usercopy: Add early abort to copy_to_user Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
[PATCH 3.12 21/86] usb: hub: Wait for connection to be reestablished after port reset Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
[PATCH 3.12 13/86] metag/usercopy: Fix src fixup in from user rapf loops Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
[PATCH 3.12 23/86] net/mlx4_core: Fix racy CQ (Completion Queue) free Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
[PATCH 3.12 34/86] zram: do not use copy_page with non-page aligned address Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
[PATCH 3.12 19/86] mtd: bcm47xxpart: fix parsing first block after aligned TRX Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
[PATCH 3.12 16/86] s390/decompressor: fix initrd corruption caused by bss clear Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
[PATCH 3.12 08/86] metag/usercopy: Drop unused macros Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
[PATCH 3.12 24/86] Input: xpad - add support for Razer Wildcat gamepad Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
[PATCH 3.12 44/86] catc: Use heap buffer for memory size test Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
[PATCH 3.12 35/86] powerpc: Disable HFSCR[TM] if TM is not supported Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
[PATCH 3.12 15/86] powerpc: Don't try to fix up misaligned load-with-reservation instructions Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
[PATCH 3.12 07/86] ring-buffer: Fix return value check in test_ringbuffer() Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
[PATCH 3.12 17/86] mm/mempolicy.c: fix error handling in set_mempolicy and mbind. Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
[PATCH 3.12 09/86] metag/usercopy: Fix alignment error checking Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
[PATCH 3.12 22/86] net/mlx4_en: Fix bad WQE issue Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
[PATCH 3.12 20/86] net/packet: fix overflow in check for priv area size Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
[PATCH 3.12 12/86] metag/usercopy: Set flags before ADDZ Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
[PATCH 3.12 11/86] metag/usercopy: Zero rest of buffer from copy_from_user Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
Re: [PATCH 3.12 00/86] 3.12.74-stable review Jiri Slaby <jslaby@suse.cz> - 2017-05-04 11:30 +0200
Re: [PATCH 3.12 00/86] 3.12.74-stable review Guenter Roeck <linux@roeck-us.net> - 2017-05-04 18:00 +0200
Re: [PATCH 3.12 00/86] 3.12.74-stable review Jiri Slaby <jslaby@suse.cz> - 2017-05-09 21:00 +0200
Re: [PATCH 3.12 00/86] 3.12.74-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2017-05-04 21:00 +0200
csiph-web