Messages in this thread Patch in this message | | | Date | Tue, 22 Nov 2005 22:20:37 +0300 | From | Oleg Nesterov <> | Subject | [PATCH] fix do_wait() vs exec() race |
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When non-leader thread does exec, de_thread adds old leader to the init's ->children list in EXIT_ZOMBIE state and drops tasklist_lock.
This means that release_task(leader) in de_thread() is racy vs do_wait() from init task.
I think de_thread() should set old leader's state to EXIT_DEAD instead.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
--- 2.6.15-rc2/fs/exec.c~ 2005-11-22 19:35:31.000000000 +0300 +++ 2.6.15-rc2/fs/exec.c 2005-11-23 00:49:23.000000000 +0300 @@ -668,7 +668,7 @@ static inline int de_thread(struct task_ if (!thread_group_leader(current)) { struct task_struct *parent; struct dentry *proc_dentry1, *proc_dentry2; - unsigned long exit_state, ptrace; + unsigned long ptrace; /* * Wait for the thread group leader to be a zombie. @@ -726,15 +726,15 @@ static inline int de_thread(struct task_ list_del(¤t->tasks); list_add_tail(¤t->tasks, &init_task.tasks); current->exit_signal = SIGCHLD; - exit_state = leader->exit_state; + + BUG_ON(leader->exit_state != EXIT_ZOMBIE); + leader->exit_state = EXIT_DEAD; write_unlock_irq(&tasklist_lock); spin_unlock(&leader->proc_lock); spin_unlock(¤t->proc_lock); proc_pid_flush(proc_dentry1); proc_pid_flush(proc_dentry2); - - BUG_ON(exit_state != EXIT_ZOMBIE); } /* - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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