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authorOleg Nesterov <oleg@redhat.com>2010-05-26 23:43:12 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2010-05-27 18:12:46 +0200
commit4a5999429739844367d0f77a65efdd7db8202779 (patch)
treefff1158fa43466b30294a7db2c4629ca14973770
parentexit: avoid sig->count in de_thread/__exit_signal synchronization (diff)
downloadlinux-4a5999429739844367d0f77a65efdd7db8202779.tar.xz
linux-4a5999429739844367d0f77a65efdd7db8202779.zip
exit: avoid sig->count in __exit_signal() to detect the group-dead case
Change __exit_signal() to check thread_group_leader() instead of atomic_dec_and_test(&sig->count). This must be equivalent, the group leader must be released only after all other threads have exited and passed __exit_signal(). Henceforth sig->count is not actually used, except in fs/proc for get_nr_threads/etc. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Roland McGrath <roland@redhat.com> Cc: Veaceslav Falico <vfalico@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--kernel/exit.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index 9220967f4256..4c70c377d21f 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -88,11 +88,12 @@ static void __exit_signal(struct task_struct *tsk)
rcu_read_lock_held() ||
lockdep_tasklist_lock_is_held());
spin_lock(&sighand->siglock);
+ atomic_dec(&sig->count);
posix_cpu_timers_exit(tsk);
- if (atomic_dec_and_test(&sig->count))
+ if (thread_group_leader(tsk)) {
posix_cpu_timers_exit_group(tsk);
- else {
+ } else {
/*
* If there is any task waiting for the group exit
* then notify it: