| 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; |