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author | Oleg Nesterov <oleg@redhat.com> | 2013-06-14 21:09:49 +0200 |
---|---|---|
committer | Al Viro <viro@zeniv.linux.org.uk> | 2013-06-15 03:39:08 +0200 |
commit | 8aac62706adaaf0fab02c4327761561c8bda9448 (patch) | |
tree | e55ad95dd0631d99703ecdd0571c54dc27e94f34 /kernel/exit.c | |
parent | fput: task_work_add() can fail if the caller has passed exit_task_work() (diff) | |
download | linux-8aac62706adaaf0fab02c4327761561c8bda9448.tar.xz linux-8aac62706adaaf0fab02c4327761561c8bda9448.zip |
move exit_task_namespaces() outside of exit_notify()
exit_notify() does exit_task_namespaces() after
forget_original_parent(). This was needed to ensure that ->nsproxy
can't be cleared prematurely, an exiting child we are going to
reparent can do do_notify_parent() and use the parent's (ours) pid_ns.
However, after 32084504 "pidns: use task_active_pid_ns in
do_notify_parent" ->nsproxy != NULL is no longer needed, we rely
on task_active_pid_ns().
Move exit_task_namespaces() from exit_notify() to do_exit(), after
exit_fs() and before exit_task_work().
This solves the problem reported by Andrey, free_ipc_ns()->shm_destroy()
does fput() which needs task_work_add().
Note: this particular problem can be fixed if we change fput(), and
that change makes sense anyway. But there is another reason to move
the callsite. The original reason for exit_task_namespaces() from
the middle of exit_notify() was subtle and it has already gone away,
now this looks confusing. And this allows us do simplify exit_notify(),
we can avoid unlock/lock(tasklist) and we can use ->exit_state instead
of PF_EXITING in forget_original_parent().
Reported-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'kernel/exit.c')
-rw-r--r-- | kernel/exit.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index af2eb3cbd499..7bb73f9d09db 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -649,7 +649,6 @@ static void exit_notify(struct task_struct *tsk, int group_dead) * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2) */ forget_original_parent(tsk); - exit_task_namespaces(tsk); write_lock_irq(&tasklist_lock); if (group_dead) @@ -795,6 +794,7 @@ void do_exit(long code) exit_shm(tsk); exit_files(tsk); exit_fs(tsk); + exit_task_namespaces(tsk); exit_task_work(tsk); check_stack_usage(); exit_thread(); |