The patch titled
set EXIT_DEAD state in do_exit(), not in schedule()
has been removed from the -mm tree. Its filename is
set-exit_dead-state-in-do_exit-not-in-schedule.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: set EXIT_DEAD state in do_exit(), not in schedule()
From: Oleg Nesterov <oleg@xxxxxxxxxx>
schedule() checks PF_DEAD on every context switch and sets ->state = EXIT_DEAD
to ensure that the exiting task will be deactivated. Note that this EXIT_DEAD
is in fact a "random" value, we can use any bit except normal TASK_XXX values.
It is better to set this state in do_exit() along with PF_DEAD flag and remove
that check in schedule().
We are safe wrt concurrent try_to_wake_up() (for example ptrace, tkill), it
can not change task's ->state: the 'state' argument of try_to_wake_up() can't
have EXIT_DEAD bit. And in case when try_to_wake_up() sees a stale value of
->state == TASK_RUNNING it will do nothing.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
kernel/exit.c | 1 +
kernel/sched.c | 3 ---
2 files changed, 1 insertion(+), 3 deletions(-)
diff -puN kernel/exit.c~set-exit_dead-state-in-do_exit-not-in-schedule kernel/exit.c
--- a/kernel/exit.c~set-exit_dead-state-in-do_exit-not-in-schedule
+++ a/kernel/exit.c
@@ -957,6 +957,7 @@ fastcall NORET_TYPE void do_exit(long co
preempt_disable();
BUG_ON(tsk->flags & PF_DEAD);
tsk->flags |= PF_DEAD;
+ tsk->state = EXIT_DEAD;
schedule();
BUG();
diff -puN kernel/sched.c~set-exit_dead-state-in-do_exit-not-in-schedule kernel/sched.c
--- a/kernel/sched.c~set-exit_dead-state-in-do_exit-not-in-schedule
+++ a/kernel/sched.c
@@ -3348,9 +3348,6 @@ need_resched_nonpreemptible:
spin_lock_irq(&rq->lock);
- if (unlikely(prev->flags & PF_DEAD))
- prev->state = EXIT_DEAD;
-
switch_count = &prev->nivcsw;
if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
switch_count = &prev->nvcsw;
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
git-block.patch
proc-readdir-race-fix-take-3-race-fix.patch
vt-rework-the-console-spawning-variables.patch
vt-make-vt_pid-a-struct-pid-making-it-pid-wrap-around-safe.patch
simplify-pid-iterators.patch
file-add-locking-to-f_getown.patch
proc-convert-task_sig-to-use-lock_task_sighand.patch
proc-convert-do_task_stat-to-use-lock_task_sighand.patch
proc-drop-tasklist-lock-in-task_state.patch
proc-properly-compute-tgid_offset.patch
proc-remove-trailing-blank-entry-from-pid_entry-arrays.patch
proc-remove-the-useless-smp-safe-comments-from-proc.patch
proc-comment-what-proc_fill_cache-does.patch
introduce-get_task_pid-to-fix-unsafe-get_pid.patch
rcu-simplify-improve-batch-tuning.patch
pidhash-temporary-debug-checks.patch
-
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