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authorOleg Nesterov <oleg@redhat.com>2010-05-26 17:43:12 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2010-05-27 12:12:46 -0400
commit4a5999429739844367d0f77a65efdd7db8202779 (patch)
treefff1158fa43466b30294a7db2c4629ca14973770
parentd344193a05da89c97e965da2c5cbf687d7385eae (diff)
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)
88 rcu_read_lock_held() || 88 rcu_read_lock_held() ||
89 lockdep_tasklist_lock_is_held()); 89 lockdep_tasklist_lock_is_held());
90 spin_lock(&sighand->siglock); 90 spin_lock(&sighand->siglock);
91 atomic_dec(&sig->count);
91 92
92 posix_cpu_timers_exit(tsk); 93 posix_cpu_timers_exit(tsk);
93 if (atomic_dec_and_test(&sig->count)) 94 if (thread_group_leader(tsk)) {
94 posix_cpu_timers_exit_group(tsk); 95 posix_cpu_timers_exit_group(tsk);
95 else { 96 } else {
96 /* 97 /*
97 * If there is any task waiting for the group exit 98 * If there is any task waiting for the group exit
98 * then notify it: 99 * then notify it: