From: Oleg Nesterov <oleg@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
Roland McGrath <roland@redhat.com>,
Stanislaw Gruszka <sgruszka@redhat.com>,
Vitaly Mayatskikh <vmayatsk@redhat.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] ptrace: wait_task_zombie: do not account traced sub-threads
Date: Mon, 15 Jun 2009 23:26:48 +0200 [thread overview]
Message-ID: <20090615212648.GA22751@redhat.com> (raw)
The bug is ancient, the fix doesn't depend on other changes in -mm.
If we trace the sub-thread of our natural child and this sub-thread exits,
we update parent->signal->cxxx fields. But we should not do this until the
whole thread-group exits, otherwise we account this thread (and all other
live threads) twice.
Add the task_detached() check. No need to check thread_group_empty(),
wait_consider_task()->delay_group_leader() already did this.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
--- PTRACE/kernel/exit.c~1_WAIT_REPARENTED 2009-06-15 21:04:49.000000000 +0200
+++ PTRACE/kernel/exit.c 2009-06-15 22:26:02.000000000 +0200
@@ -1189,7 +1189,7 @@ static int wait_task_zombie(struct wait_
traced = ptrace_reparented(p);
- if (likely(!traced)) {
+ if (likely(!traced) && likely(!task_detached(p))) {
struct signal_struct *psig;
struct signal_struct *sig;
struct task_cputime cputime;
next reply other threads:[~2009-06-15 21:31 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-15 21:26 Oleg Nesterov [this message]
2009-06-16 0:45 ` [PATCH 1/2] ptrace: wait_task_zombie: do not account traced sub-threads Roland McGrath
2009-06-17 19:48 ` [rfc] ptrace: wait_task_zombie: fix the racy EXIT_ZOMBIE setting Oleg Nesterov
2009-06-18 18:47 ` [PATCH] ptrace-wait_task_zombie-do-not-account-traced-sub-threads-fix Oleg Nesterov
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