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authorOleg Nesterov <oleg@tv-sign.ru>2006-02-15 22:13:24 +0300
committerLinus Torvalds <torvalds@g5.osdl.org>2006-02-15 10:21:23 -0800
commit3f17da699431ec48540beabc55c54d4b5e66c8e7 (patch)
tree0cc68e5daea5d4532a0225aa47cce193a32f6655 /kernel
parent7775aa7690c26b3c5606090a43533a7a7429eb91 (diff)
[PATCH] fix kill_proc_info() vs CLONE_THREAD race
There is a window after copy_process() unlocks ->sighand.siglock and before it adds the new thread to the thread list. In that window __group_complete_signal(SIGKILL) will not see the new thread yet, so this thread will start running while the whole thread group was supposed to exit. I beleive we have another good reason to place attach_pid(PID/TGID) under ->sighand.siglock. We can do the same for release_task()->__unhash_process() de_thread()->switch_exec_pids() After that we don't need tasklist_lock to iterate over the thread list, and we can simplify things, see for example do_sigaction() or sys_times(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/fork.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index 8e88b374cee..3683ce10f4a 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1123,8 +1123,8 @@ static task_t *copy_process(unsigned long clone_flags,
p->real_parent = current;
p->parent = p->real_parent;
+ spin_lock(&current->sighand->siglock);
if (clone_flags & CLONE_THREAD) {
- spin_lock(&current->sighand->siglock);
/*
* Important: if an exit-all has been started then
* do not create this new thread - the whole thread
@@ -1162,8 +1162,6 @@ static task_t *copy_process(unsigned long clone_flags,
*/
p->it_prof_expires = jiffies_to_cputime(1);
}
-
- spin_unlock(&current->sighand->siglock);
}
/*
@@ -1189,6 +1187,7 @@ static task_t *copy_process(unsigned long clone_flags,
nr_threads++;
total_forks++;
+ spin_unlock(&current->sighand->siglock);
write_unlock_irq(&tasklist_lock);
proc_fork_connector(p);
return p;