From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id B8A4260021B for ; Wed, 9 Dec 2009 19:53:35 -0500 (EST) Message-Id: <20091210004703.148689096@linutronix.de> Date: Thu, 10 Dec 2009 00:53:07 -0000 From: Thomas Gleixner Subject: [patch 4/9] oom: Add missing rcu protection of __task_cred() in dump_tasks References: <20091210001308.247025548@linutronix.de> Content-Disposition: inline; filename=oom-fix-missing-rcu-protection-of-__task_cred.patch Sender: owner-linux-mm@kvack.org To: LKML Cc: "Paul E. McKenney" , Dipankar Sarma , Ingo Molnar , Peter Zijlstra , Oleg Nesterov , Al Viro , James Morris , David Howells , Andrew Morton , Linus Torvalds , linux-mm@kvack.org List-ID: dump_tasks accesses __task_cred() without being in a RCU read side critical section. tasklist_lock is not protecting that when CONFIG_TREE_PREEMPT_RCU=y. Add a rcu_read_lock/unlock() section around the code which accesses __task_cred(). Signed-off-by: Thomas Gleixner Cc: linux-mm@kvack.org --- mm/oom_kill.c | 3 +++ 1 file changed, 3 insertions(+) Index: linux-2.6-tip/mm/oom_kill.c =================================================================== --- linux-2.6-tip.orig/mm/oom_kill.c +++ linux-2.6-tip/mm/oom_kill.c @@ -329,10 +329,13 @@ static void dump_tasks(const struct mem_ task_unlock(p); continue; } + /* Protect __task_cred() access */ + rcu_read_lock(); printk(KERN_INFO "[%5d] %5d %5d %8lu %8lu %3d %3d %s\n", p->pid, __task_cred(p)->uid, p->tgid, mm->total_vm, get_mm_rss(mm), (int)task_cpu(p), p->signal->oom_adj, p->comm); + rcu_read_unlock(); task_unlock(p); } while_each_thread(g, p); } -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org