From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Sasha Levin To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" CC: Ravi Bangoria , Michael Ellerman , Sasha Levin Subject: [PATCH AUTOSEL for 3.18 09/25] powerpc/perf: Fix oops when grouping different pmu events Date: Sun, 28 Jan 2018 22:29:47 +0000 Message-ID: <20180128222931.7781-9-alexander.levin@microsoft.com> References: <20180128222931.7781-1-alexander.levin@microsoft.com> In-Reply-To: <20180128222931.7781-1-alexander.levin@microsoft.com> Content-Language: en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: From: Ravi Bangoria [ 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 Reviewed-By: Madhavan Srinivasan Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin --- arch/powerpc/perf/core-book3s.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3= s.c index ba5f0580d5b0..e97c0e56eaad 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -1376,7 +1376,7 @@ static int collect_events(struct perf_event *group, i= nt max_count, int n =3D 0; struct perf_event *event; =20 - if (!is_software_event(group)) { + if (group->pmu->task_ctx_nr =3D=3D perf_hw_context) { if (n >=3D max_count) return -1; ctrs[n] =3D group; @@ -1384,7 +1384,7 @@ static int collect_events(struct perf_event *group, i= nt max_count, events[n++] =3D group->hw.config; } list_for_each_entry(event, &group->sibling_list, group_entry) { - if (!is_software_event(event) && + if (event->pmu->task_ctx_nr =3D=3D perf_hw_context && event->state !=3D PERF_EVENT_STATE_OFF) { if (n >=3D max_count) return -1; --=20 2.11.0