diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2011-01-19 19:22:28 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2011-01-19 20:04:28 +0100 |
| commit | 8550d7cb6ed6c89add49c3b6ad4c753ab8a3d7f9 (patch) | |
| tree | 9942aa32e7706bbb9bf52b9aecd542008f50d5aa /kernel/perf_event.c | |
| parent | perf: Fix find_get_context() vs perf_event_exit_task() race (diff) | |
| download | linux-8550d7cb6ed6c89add49c3b6ad4c753ab8a3d7f9.tar.xz linux-8550d7cb6ed6c89add49c3b6ad4c753ab8a3d7f9.zip | |
perf: Fix perf_event_init_task()/perf_event_free_task() interaction
perf_event_init_task() should clear child->perf_event_ctxp[]
before anything else. Otherwise, if
perf_event_init_context(perf_hw_context) fails,
perf_event_free_task() can free perf_event_ctxp[perf_sw_context]
copied from parent->perf_event_ctxp[] by dup_task_struct().
Also move the initialization of perf_event_mutex and
perf_event_list from perf_event_init_context() to
perf_event_init_context().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Roland McGrath <roland@redhat.com>
LKML-Reference: <20110119182228.GC12183@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/perf_event.c')
| -rw-r--r-- | kernel/perf_event.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 4ec55ef5810c..244ca3acb0ee 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -6446,11 +6446,6 @@ int perf_event_init_context(struct task_struct *child, int ctxn) unsigned long flags; int ret = 0; - child->perf_event_ctxp[ctxn] = NULL; - - mutex_init(&child->perf_event_mutex); - INIT_LIST_HEAD(&child->perf_event_list); - if (likely(!parent->perf_event_ctxp[ctxn])) return 0; @@ -6539,6 +6534,10 @@ int perf_event_init_task(struct task_struct *child) { int ctxn, ret; + memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp)); + mutex_init(&child->perf_event_mutex); + INIT_LIST_HEAD(&child->perf_event_list); + for_each_task_context_nr(ctxn) { ret = perf_event_init_context(child, ctxn); if (ret) |