• Jiri Olsa's avatar
    perf: Clone child context from parent context pmu · 734df5ab
    Jiri Olsa authored
    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: default avatarVince Weaver <vincent.weaver@maine.edu>
    Signed-off-by: default avatarJiri 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>
    Cc: <stable@kernel.org>
    Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
    Link: http://lkml.kernel.org/r/1373384651-6109-1-git-send-email-jolsa@redhat.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
    734df5ab
core.c 182 KB