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authorTejun Heo <tj@kernel.org>2011-11-22 00:32:23 +0400
committerTejun Heo <tj@kernel.org>2011-11-22 00:32:23 +0400
commita585042f7b933539a0b6bc63650c2d49ffb2e55d (patch)
treebb93d05050e04c4bcd53fdf535239e6312fb62e2 /kernel/exit.c
parenta5be2d0d1a8746e7be5210e3d6b904455000443c (diff)
downloadlinux-a585042f7b933539a0b6bc63650c2d49ffb2e55d.tar.xz
freezer: remove racy clear_freeze_flag() and set PF_NOFREEZE on dead tasks
clear_freeze_flag() in exit_mm() is racy. Freezing can start afterwards. Remove it. Skipping freezer for exiting task will be properly implemented later. Also, freezable() was testing exit_state directly to make system freezer ignore dead tasks. Let the exiting task set PF_NOFREEZE after entering TASK_DEAD instead. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com>
Diffstat (limited to 'kernel/exit.c')
-rw-r--r--kernel/exit.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index d0b7d988f873..95a4141d07e7 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -679,8 +679,6 @@ static void exit_mm(struct task_struct * tsk)
tsk->mm = NULL;
up_read(&mm->mmap_sem);
enter_lazy_tlb(mm, current);
- /* We don't want this task to be frozen prematurely */
- clear_freeze_flag(tsk);
task_unlock(tsk);
mm_update_next_owner(mm);
mmput(mm);
@@ -1040,6 +1038,7 @@ NORET_TYPE void do_exit(long code)
exit_rcu();
/* causes final put_task_struct in finish_task_switch(). */
tsk->state = TASK_DEAD;
+ tsk->flags |= PF_NOFREEZE; /* tell freezer to ignore us */
schedule();
BUG();
/* Avoid "noreturn function does return". */