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authorOleg Nesterov <oleg@tv-sign.ru>2005-11-23 13:37:43 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2005-11-23 16:08:39 -0800
commit962b564cf1ec8041e8890a3c3847e3a630a08f42 (patch)
treea238616355c02496177e486d78f9a75911e943b6 /fs/exec.c
parent8bf1101bd52573e0573e374d56d2feecdbb5e444 (diff)
downloadop-kernel-dev-962b564cf1ec8041e8890a3c3847e3a630a08f42.zip
op-kernel-dev-962b564cf1ec8041e8890a3c3847e3a630a08f42.tar.gz
[PATCH] fix do_wait() vs exec() race
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> Cc: george anzinger <george@mvista.com> Cc: Roland Dreier <rolandd@cisco.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/exec.c')
-rw-r--r--fs/exec.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/fs/exec.c b/fs/exec.c
index c466fec..1f8a9fd 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -668,7 +668,7 @@ static inline int de_thread(struct task_struct *tsk)
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_struct *tsk)
list_del(&current->tasks);
list_add_tail(&current->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(&current->proc_lock);
proc_pid_flush(proc_dentry1);
proc_pid_flush(proc_dentry2);
-
- BUG_ON(exit_state != EXIT_ZOMBIE);
}
/*
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