Messages in this thread Patch in this message | | | Date | Wed, 19 Jan 2011 19:22:28 +0100 | From | Oleg Nesterov <> | Subject | [PATCH 2/2] perf: fix perf_event_init_task()/perf_event_free_task() interaction |
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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> ---
kernel/perf_event.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-)
--- git/kernel/perf_event.c~4_perf_event_init_task 2011-01-19 17:41:16.000000000 +0100 +++ git/kernel/perf_event.c 2011-01-19 18:49:23.000000000 +0100 @@ -6446,11 +6446,6 @@ int perf_event_init_context(struct task_ 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; @@ -6540,6 +6535,10 @@ int perf_event_init_task(struct task_str { 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)
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