3fb45733df "freezer: make exiting tasks properly unfreezable" removed clear_freeze_flag() from exit path and set PF_NOFREEZE right after PTRACE_EVENT_EXIT; however, Oleg pointed out that following exit paths may cause interaction with device drivers after PM freezer consider the system frozen. There's no try_to_freeze() call in the exit path and the only necessary guarantee is that freezer doesn't hang waiting for zombies. Set PF_NOFREEZE right before setting tsk->state to TASK_DEAD instead. Signed-off-by: Tejun Heo <tj@xxxxxxxxxx> Reported-by: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: "Rafael J. Wysocki" <rjw@xxxxxxx> --- kernel/exit.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) Index: work/kernel/exit.c =================================================================== --- work.orig/kernel/exit.c +++ work/kernel/exit.c @@ -913,12 +913,6 @@ NORET_TYPE void do_exit(long code) ptrace_event(PTRACE_EVENT_EXIT, code); - /* - * With ptrace notification done, there's no point in freezing from - * here on. Disallow freezing. - */ - current->flags |= PF_NOFREEZE; - validate_creds_for_do_exit(tsk); /* @@ -1044,6 +1038,10 @@ NORET_TYPE void do_exit(long code) preempt_disable(); exit_rcu(); + + /* this task is now dead and freezer should ignore it */ + current->flags |= PF_NOFREEZE; + /* causes final put_task_struct in finish_task_switch(). */ tsk->state = TASK_DEAD; schedule(); _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
