| 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 |
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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 <tglx@linutronix.de> 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); }
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