| Message ID | 1453853642-23175-1-git-send-email-kamal@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c index 71fc402..dbe8d89 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_ds.c +++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c @@ -1027,6 +1027,13 @@ get_next_pebs_record_by_bit(void *base, void *top, int bit) void *at; u64 pebs_status; + /* + * fmt0 does not have a status bitfield (does not use + * perf_record_nhm format) + */ + if (x86_pmu.intel_cap.pebs_format < 1) + return base; + if (base == NULL) return NULL; @@ -1112,7 +1119,7 @@ static void intel_pmu_drain_pebs_core(struct pt_regs *iregs) if (!event->attr.precise_ip) return; - n = (top - at) / x86_pmu.pebs_record_size; + n = top - at; if (n <= 0) return;
This is a note to let you know that I have just added a patch titled perf/x86: fix PEBS issues on Intel Atom/Core2 to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue This patch is scheduled to be released in version 4.2.8-ckt3. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 4.2.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ---8<------------------------------------------------------------ From 029260958a232c329da7b896344dc1fa43b83f50 Mon Sep 17 00:00:00 2001 From: Stephane Eranian <eranian@google.com> Date: Thu, 3 Dec 2015 23:33:18 +0100 Subject: perf/x86: fix PEBS issues on Intel Atom/Core2 commit 1424a09a9e1839285e948d4ea9fdfca26c9a2086 upstream. This patch fixes broken PEBS support on Intel Atom and Core2 due to wrong pointer arithmetic in intel_pmu_drain_pebs_core(). The get_next_pebs_record_by_bit() was called on PEBS format fmt0 which does not use the pebs_record_nhm layout. Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: kan.liang@intel.com Fixes: 21509084f999 ("perf/x86/intel: Handle multiple records in the PEBS buffer") Link: http://lkml.kernel.org/r/1449182000-31524-3-git-send-email-eranian@google.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- arch/x86/kernel/cpu/perf_event_intel_ds.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) -- 1.9.1