| From: Jiri Olsa <jolsa@redhat.com> |
| Date: Tue, 9 Jul 2013 17:44:10 +0200 |
| Subject: perf: Clone child context from parent context pmu |
| |
| commit 734df5ab549ca44f40de0f07af1c8803856dfb18 upstream. |
| |
| Currently when the child context for inherited events is |
| created, it's based on the pmu object of the first event |
| of the parent context. |
| |
| This is wrong for the following scenario: |
| |
| - HW context having HW and SW event |
| - HW event got removed (closed) |
| - SW event stays in HW context as the only event |
| and its pmu is used to clone the child context |
| |
| The issue starts when the cpu context object is touched |
| based on the pmu context object (__get_cpu_context). In |
| this case the HW context will work with SW cpu context |
| ending up with following WARN below. |
| |
| Fixing this by using parent context pmu object to clone |
| from child context. |
| |
| Addresses the following warning reported by Vince Weaver: |
| |
| [ 2716.472065] ------------[ cut here ]------------ |
| [ 2716.476035] WARNING: at kernel/events/core.c:2122 task_ctx_sched_out+0x3c/0x) |
| [ 2716.476035] Modules linked in: nfsd auth_rpcgss oid_registry nfs_acl nfs locn |
| [ 2716.476035] CPU: 0 PID: 3164 Comm: perf_fuzzer Not tainted 3.10.0-rc4 #2 |
| [ 2716.476035] Hardware name: AOpen DE7000/nMCP7ALPx-DE R1.06 Oct.19.2012, BI2 |
| [ 2716.476035] 0000000000000000 ffffffff8102e215 0000000000000000 ffff88011fc18 |
| [ 2716.476035] ffff8801175557f0 0000000000000000 ffff880119fda88c ffffffff810ad |
| [ 2716.476035] ffff880119fda880 ffffffff810af02a 0000000000000009 ffff880117550 |
| [ 2716.476035] Call Trace: |
| [ 2716.476035] [<ffffffff8102e215>] ? warn_slowpath_common+0x5b/0x70 |
| [ 2716.476035] [<ffffffff810ab2bd>] ? task_ctx_sched_out+0x3c/0x5f |
| [ 2716.476035] [<ffffffff810af02a>] ? perf_event_exit_task+0xbf/0x194 |
| [ 2716.476035] [<ffffffff81032a37>] ? do_exit+0x3e7/0x90c |
| [ 2716.476035] [<ffffffff810cd5ab>] ? __do_fault+0x359/0x394 |
| [ 2716.476035] [<ffffffff81032fe6>] ? do_group_exit+0x66/0x98 |
| [ 2716.476035] [<ffffffff8103dbcd>] ? get_signal_to_deliver+0x479/0x4ad |
| [ 2716.476035] [<ffffffff810ac05c>] ? __perf_event_task_sched_out+0x230/0x2d1 |
| [ 2716.476035] [<ffffffff8100205d>] ? do_signal+0x3c/0x432 |
| [ 2716.476035] [<ffffffff810abbf9>] ? ctx_sched_in+0x43/0x141 |
| [ 2716.476035] [<ffffffff810ac2ca>] ? perf_event_context_sched_in+0x7a/0x90 |
| [ 2716.476035] [<ffffffff810ac311>] ? __perf_event_task_sched_in+0x31/0x118 |
| [ 2716.476035] [<ffffffff81050dd9>] ? mmdrop+0xd/0x1c |
| [ 2716.476035] [<ffffffff81051a39>] ? finish_task_switch+0x7d/0xa6 |
| [ 2716.476035] [<ffffffff81002473>] ? do_notify_resume+0x20/0x5d |
| [ 2716.476035] [<ffffffff813654f5>] ? retint_signal+0x3d/0x78 |
| [ 2716.476035] ---[ end trace 827178d8a5966c3d ]--- |
| |
| Reported-by: Vince Weaver <vincent.weaver@maine.edu> |
| Signed-off-by: Jiri Olsa <jolsa@redhat.com> |
| Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> |
| Cc: Frederic Weisbecker <fweisbec@gmail.com> |
| Cc: Ingo Molnar <mingo@elte.hu> |
| Cc: Namhyung Kim <namhyung@kernel.org> |
| Cc: Paul Mackerras <paulus@samba.org> |
| Cc: Arnaldo Carvalho de Melo <acme@redhat.com> |
| Signed-off-by: Peter Zijlstra <peterz@infradead.org> |
| Link: http://lkml.kernel.org/r/1373384651-6109-1-git-send-email-jolsa@redhat.com |
| Signed-off-by: Ingo Molnar <mingo@kernel.org> |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| kernel/events/core.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/kernel/events/core.c |
| +++ b/kernel/events/core.c |
| @@ -6797,7 +6797,7 @@ inherit_task_group(struct perf_event *ev |
| * child. |
| */ |
| |
| - child_ctx = alloc_perf_context(event->pmu, child); |
| + child_ctx = alloc_perf_context(parent_ctx->pmu, child); |
| if (!child_ctx) |
| return -ENOMEM; |
| |
