diff options
| author | Vincent Palatin <vpalatin@chromium.org> | 2012-11-30 12:15:32 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-12-10 10:59:39 -0800 |
| commit | 1b9dd61a10bed126661645cbf2623965fbbdefb3 (patch) | |
| tree | 45f4d00336b376380df5d66333416dc8e44cbf49 /kernel | |
| parent | 659cca40ff27f7d73a0c49ac6c8d8b3838202524 (diff) | |
x86, fpu: Avoid FPU lazy restore after suspend
commit 644c154186386bb1fa6446bc5e037b9ed098db46 upstream.
When a cpu enters S3 state, the FPU state is lost.
After resuming for S3, if we try to lazy restore the FPU for a process running
on the same CPU, this will result in a corrupted FPU context.
Ensure that "fpu_owner_task" is properly invalided when (re-)initializing a CPU,
so nobody will try to lazy restore a state which doesn't exist in the hardware.
Tested with a 64-bit kernel on a 4-core Ivybridge CPU with eagerfpu=off,
by doing thousands of suspend/resume cycles with 4 processes doing FPU
operations running. Without the patch, a process is killed after a
few hundreds cycles by a SIGFPE.
Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
Cc: Duncan Laurie <dlaurie@chromium.org>
Cc: Olof Johansson <olofj@chromium.org>
Link: http://lkml.kernel.org/r/1354306532-1014-1-git-send-email-vpalatin@chromium.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
0 files changed, 0 insertions, 0 deletions