This is a note to let you know that I've just added the patch titled
powerpc/perf: Fix oops when grouping different pmu events
to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: powerpc-perf-fix-oops-when-grouping-different-pmu-events.patch and it can be found in the queue-3.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Fri Feb 23 12:01:27 CET 2018
From: Ravi Bangoria ravi.bangoria@linux.vnet.ibm.com Date: Thu, 30 Nov 2017 14:03:22 +0530 Subject: powerpc/perf: Fix oops when grouping different pmu events
From: Ravi Bangoria ravi.bangoria@linux.vnet.ibm.com
[ Upstream commit 5aa04b3eb6fca63d2e9827be656dcadc26d54e11 ]
When user tries to group imc (In-Memory Collections) event with normal event, (sometime) kernel crashes with following log:
Faulting instruction address: 0x00000000 [link register ] c00000000010ce88 power_check_constraints+0x128/0x980 ... c00000000010e238 power_pmu_event_init+0x268/0x6f0 c0000000002dc60c perf_try_init_event+0xdc/0x1a0 c0000000002dce88 perf_event_alloc+0x7b8/0xac0 c0000000002e92e0 SyS_perf_event_open+0x530/0xda0 c00000000000b004 system_call+0x38/0xe0
'event_base' field of 'struct hw_perf_event' is used as flags for normal hw events and used as memory address for imc events. While grouping these two types of events, collect_events() tries to interpret imc 'event_base' as a flag, which causes a corruption resulting in a crash.
Consider only those events which belongs to 'perf_hw_context' in collect_events().
Signed-off-by: Ravi Bangoria ravi.bangoria@linux.vnet.ibm.com Reviewed-By: Madhavan Srinivasan maddy@linux.vnet.ibm.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/powerpc/perf/core-book3s.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -1376,7 +1376,7 @@ static int collect_events(struct perf_ev int n = 0; struct perf_event *event;
- if (!is_software_event(group)) { + if (group->pmu->task_ctx_nr == perf_hw_context) { if (n >= max_count) return -1; ctrs[n] = group; @@ -1384,7 +1384,7 @@ static int collect_events(struct perf_ev events[n++] = group->hw.config; } list_for_each_entry(event, &group->sibling_list, group_entry) { - if (!is_software_event(event) && + if (event->pmu->task_ctx_nr == perf_hw_context && event->state != PERF_EVENT_STATE_OFF) { if (n >= max_count) return -1;
Patches currently in stable-queue which might be from ravi.bangoria@linux.vnet.ibm.com are
queue-3.18/perf-top-fix-window-dimensions-change-handling.patch queue-3.18/powerpc-perf-fix-oops-when-grouping-different-pmu-events.patch