From: Oleg Nesterov Date: Wed, 11 Sep 2013 15:47:26 +0000 (+0200) Subject: uprobes: Fix utask->depth accounting in handle_trampoline() X-Git-Tag: firefly_0821_release~6453^2~779 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=73e2c2b7c105e46344eb409575a4508f24a82eee;p=firefly-linux-kernel-4.4.55.git uprobes: Fix utask->depth accounting in handle_trampoline() commit 878b5a6efd38030c7a90895dc8346e8fb1e09b4c upstream. 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 Reported-by: Hemant Kumar Shaw Signed-off-by: Oleg Nesterov Acked-by: Anton Arapov Cc: masami.hiramatsu.pt@hitachi.com Cc: srikar@linux.vnet.ibm.com Cc: systemtap@sourceware.org Link: http://lkml.kernel.org/r/20130911154726.GA8093@redhat.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index f3569747d629..ad8e1bdca70e 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); }