From: Stephane Eranian Date: Fri, 15 Mar 2013 13:26:07 +0000 (+0100) Subject: perf,x86: fix kernel crash with PEBS/BTS after suspend/resume X-Git-Tag: v3.9-rc3~11 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1d9d8639c063caf6efc2447f5f26aa637f844ff6;p=pandora-kernel.git perf,x86: fix kernel crash with PEBS/BTS after suspend/resume 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 Signed-off-by: Stephane Eranian Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed