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authorOleg Nesterov <oleg@redhat.com>2011-01-19 19:22:28 +0100
committerIngo Molnar <mingo@elte.hu>2011-01-19 20:04:28 +0100
commit8550d7cb6ed6c89add49c3b6ad4c753ab8a3d7f9 (patch)
tree9942aa32e7706bbb9bf52b9aecd542008f50d5aa /kernel/perf_event.c
parentdbe08d82ce3967ccdf459f7951d02589cf967300 (diff)
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.c9
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)