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b0d50c7b5d
linux/arch/x86
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Josh Poimboeuf b0d50c7b5d x86/unwind: Silence more entry-code related warnings 
Borislav Petkov reported the following unwinder warning:

  WARNING: kernel stack regs at ffffc9000024fea8 in udevadm:92 has bad 'bp' value 00007fffc4614d30
  unwind stack type:0 next_sp:          (null) mask:0x6 graph_idx:0
  ffffc9000024fea8: 000055a6100e9b38 (0x55a6100e9b38)
  ffffc9000024feb0: 000055a6100e9b35 (0x55a6100e9b35)
  ffffc9000024feb8: 000055a6100e9f68 (0x55a6100e9f68)
  ffffc9000024fec0: 000055a6100e9f50 (0x55a6100e9f50)
  ffffc9000024fec8: 00007fffc4614d30 (0x7fffc4614d30)
  ffffc9000024fed0: 000055a6100eaf50 (0x55a6100eaf50)
  ffffc9000024fed8: 0000000000000000 ...
  ffffc9000024fee0: 0000000000000100 (0x100)
  ffffc9000024fee8: ffff8801187df488 (0xffff8801187df488)
  ffffc9000024fef0: 00007ffffffff000 (0x7ffffffff000)
  ffffc9000024fef8: 0000000000000000 ...
  ffffc9000024ff10: ffffc9000024fe98 (0xffffc9000024fe98)
  ffffc9000024ff18: 00007fffc4614d00 (0x7fffc4614d00)
  ffffc9000024ff20: ffffffffffffff10 (0xffffffffffffff10)
  ffffc9000024ff28: ffffffff811c6c1f (SyS_newlstat+0xf/0x10)
  ffffc9000024ff30: 0000000000000010 (0x10)
  ffffc9000024ff38: 0000000000000296 (0x296)
  ffffc9000024ff40: ffffc9000024ff50 (0xffffc9000024ff50)
  ffffc9000024ff48: 0000000000000018 (0x18)
  ffffc9000024ff50: ffffffff816b2e6a (entry_SYSCALL_64_fastpath+0x18/0xa8)
  ...

It unwinded from an interrupt which came in right after entry code
called into a C syscall handler, before it had a chance to set up the
frame pointer, so regs->bp still had its user space value.

Add a check to silence warnings in such a case, where an interrupt
has occurred and regs->sp is almost at the end of the stack.

Reported-by: Borislav Petkov <bp@suse.de>
Tested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: c32c47c68a ("x86/unwind: Warn on bad frame pointer")
Link: http://lkml.kernel.org/r/c695f0d0d4c2cfe6542b90e2d0520e11eb901eb5.1493171120.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-04-26 08:19:05 +02:00
..
boot Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-02-20 14:04:37 -08:00
configs x86/build/x86_64_defconfig: Enable CONFIG_R8169 2017-03-06 11:47:43 +01:00
crypto crypto: sha512-mb - Protect sha512 mb ctx mgr access 2017-02-11 17:50:41 +08:00
entry x86/ftrace: Move the ftrace specific code out of entry_32.S 2017-03-24 10:14:07 +01:00
events Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-17 13:59:52 -07:00
hyperv x86/hyperv: Hide unused label 2017-03-01 10:51:40 +01:00
ia32 sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
include x86/unwind: Silence entry-related warnings 2017-04-14 10:20:06 +02:00
kernel x86/unwind: Silence more entry-code related warnings 2017-04-26 08:19:05 +02:00
kvm KVM: nVMX: do not warn when MSR bitmap address is not backed 2017-03-09 15:34:51 +01:00
lguest
lib x86/asm: Optimize clear_page() 2017-03-07 08:28:00 +01:00
math-emu
mm x86/mpx: Make unnecessarily global function static 2017-03-16 09:17:05 +01:00
net bpf: fix unlocking of jited image when module ronx not set 2017-02-21 13:30:14 -05:00
oprofile
pci features and fixes for 4.11 rc1 2017-03-09 12:23:30 -08:00
platform x86/platform/intel-mid: Add power button support for Merrifield 2017-03-13 22:08:28 +01:00
power
purgatory kexec, x86/purgatory: Unbreak it and clean it up 2017-03-10 20:55:09 +01:00
ras x86/ras/amd/inj: Change dependency 2017-01-24 09:14:55 +01:00
realmode
tools
um x86/debug: Implement __WARN() using UD0 2017-03-27 10:20:28 +02:00
video
xen sched/headers: Prepare to remove the <linux/mm_types.h> dependency from <linux/sched.h> 2017-03-02 08:42:37 +01:00
.gitignore
Kbuild Drivers: hv vmbus: Move Hypercall page setup out of common code 2017-01-19 11:42:07 +01:00
Kconfig x86/ftrace: Add -mfentry support to x86_32 with DYNAMIC_FTRACE set 2017-03-24 10:14:07 +01:00
Kconfig.cpu
Kconfig.debug mm: add arch-independent testcases for RODATA 2017-02-27 18:43:48 -08:00
Makefile
Makefile_32.cpu
Makefile.um