]> git.baikalelectronics.ru Git - kernel.git/commit
x86/nmi/64: Fix a paravirt stack-clobbering bug in the NMI code
authorAndy Lutomirski <luto@kernel.org>
Sun, 20 Sep 2015 23:32:05 +0000 (16:32 -0700)
committerThomas Gleixner <tglx@linutronix.de>
Tue, 22 Sep 2015 20:40:36 +0000 (22:40 +0200)
commitb9f60bcd4b86159a66a162587c10d809e392e4f2
tree216347000c44ee61270ab02cba8a838b01ee3f4f
parent02b2fec704183f2a00e0dabd0ba0376021a8e3a7
x86/nmi/64: Fix a paravirt stack-clobbering bug in the NMI code

The NMI entry code that switches to the normal kernel stack needs to
be very careful not to clobber any extra stack slots on the NMI
stack.  The code is fine under the assumption that SWAPGS is just a
normal instruction, but that assumption isn't really true.  Use
SWAPGS_UNSAFE_STACK instead.

This is part of a fix for some random crashes that Sasha saw.

Fixes: c2c5d055fbdf ("x86/nmi/64: Switch stacks on userspace NMI entry")
Reported-and-tested-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/974bc40edffdb5c2950a5c4977f821a446b76178.1442791737.git.luto@kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
arch/x86/entry/entry_64.S