Messages in this thread Patch in this message | | | Date | Thu, 12 Sep 2013 04:11:37 -0700 | From | tip-bot for Oleg Nesterov <> | Subject | [tip:perf/urgent] uprobes: Fix utask-> depth accounting in handle_trampoline() |
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Commit-ID: 878b5a6efd38030c7a90895dc8346e8fb1e09b4c Gitweb: http://git.kernel.org/tip/878b5a6efd38030c7a90895dc8346e8fb1e09b4c Author: Oleg Nesterov <oleg@redhat.com> AuthorDate: Wed, 11 Sep 2013 17:47:26 +0200 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Thu, 12 Sep 2013 08:00:55 +0200
uprobes: Fix utask->depth accounting in handle_trampoline()
Currently utask->depth is simply the number of allocated/pending return_instance's in uprobe_task->return_instances list.
handle_trampoline() should decrement this counter every time we handle/free an instance, but due to typo it does this only if ->chained == T. This means that in the likely case this counter is never decremented and the probed task can't report more than MAX_URETPROBE_DEPTH events.
Reported-by: Mikhail Kulemin <Mikhail.Kulemin@ru.ibm.com> Reported-by: Hemant Kumar Shaw <hkshaw@linux.vnet.ibm.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Anton Arapov <anton@redhat.com> Cc: masami.hiramatsu.pt@hitachi.com Cc: srikar@linux.vnet.ibm.com Cc: systemtap@sourceware.org Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20130911154726.GA8093@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> --- kernel/events/uprobes.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index f356974..ad8e1bd 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1682,12 +1682,10 @@ static bool handle_trampoline(struct pt_regs *regs) tmp = ri; ri = ri->next; kfree(tmp); + utask->depth--; if (!chained) break; - - utask->depth--; - BUG_ON(!ri); }
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