x86/entry/traps: Clear TIF_BLOCKSTEP on all debug exceptions
authorAndy Lutomirski <luto@kernel.org>
Thu, 10 Mar 2016 03:00:28 +0000 (19:00 -0800)
committerIngo Molnar <mingo@kernel.org>
Thu, 10 Mar 2016 08:48:13 +0000 (09:48 +0100)
commit81edd9f69a6fd214fdbe66b43de6aa1610c84c63
treec93d1ac792c7864ff0836b159e69f30c5032bf17
parentc2c9b52fab0d0cf993476ed4c34f24da5a1205ae
x86/entry/traps: Clear TIF_BLOCKSTEP on all debug exceptions

The SDM says that debug exceptions clear BTF, and we need to keep
TIF_BLOCKSTEP in sync with BTF.  Clear it unconditionally and improve
the comment.

I suspect that the fact that kmemcheck could cause TIF_BLOCKSTEP not
to be cleared was just an oversight.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Andy Lutomirski <luto@amacapital.net>
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: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/fa86e55d196e6dde5b38839595bde2a292c52fdc.1457578375.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch/x86/kernel/traps.c