1. 20 Feb, 2012 1 commit
    • Steven Rostedt's avatar
      x86/nmi: Test saved %cs in NMI to determine nested NMI case · 45d5a168
      Steven Rostedt authored
      Currently, the NMI handler tests if it is nested by checking the
      special variable saved on the stack (set during NMI handling)
      and whether the saved stack is the NMI stack as well (to prevent
      the race when the variable is set to zero).
      
      But userspace may set their %rsp to any value as long as they do
      not derefence it, and it may make it point to the NMI stack,
      which will prevent NMIs from triggering while the userspace app
      is running. (I tested this, and it is indeed the case)
      
      Add another check to determine nested NMIs by looking at the
      saved %cs (code segment register) and making sure that it is the
      kernel code segment.
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: <stable@kernel.org>
      Link: http://lkml.kernel.org/r/1329687817.1561.27.camel@acer.local.homeSigned-off-by: default avatarIngo Molnar <mingo@elte.hu>
      45d5a168
  2. 09 Feb, 2012 1 commit
  3. 07 Feb, 2012 1 commit
  4. 04 Feb, 2012 26 commits
  5. 03 Feb, 2012 4 commits
  6. 02 Feb, 2012 7 commits