diff options
| author | Stephane Eranian <eranian@google.com> | 2013-03-15 14:26:07 +0100 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2013-03-27 02:40:54 +0000 |
| commit | 8da1a618f37700141f1cf6e3a9c16dc1b1e261c9 (patch) | |
| tree | 93c90365323a03b14ef17bafb64aa0a39cf2d852 /fs/eventfd.c | |
| parent | dc71dd5c5bd96038a90f4efc0c127e21ea86bba1 (diff) | |
perf,x86: fix kernel crash with PEBS/BTS after suspend/resume
commit 1d9d8639c063caf6efc2447f5f26aa637f844ff6 upstream.
This patch fixes a kernel crash when using precise sampling (PEBS)
after a suspend/resume. Turns out the CPU notifier code is not invoked
on CPU0 (BP). Therefore, the DS_AREA (used by PEBS) is not restored properly
by the kernel and keeps it power-on/resume value of 0 causing any PEBS
measurement to crash when running on CPU0.
The workaround is to add a hook in the actual resume code to restore
the DS Area MSR value. It is invoked for all CPUS. So for all but CPU0,
the DS_AREA will be restored twice but this is harmless.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'fs/eventfd.c')
0 files changed, 0 insertions, 0 deletions