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>
This commit is contained in:
Oleg Nesterov 2013-09-11 17:47:26 +02:00 committed by Ingo Molnar
parent 6113af14c8
commit 878b5a6efd
1 changed files with 1 additions and 3 deletions

View File

@ -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);
}