The patch titled
Subject: exit: make setting exit_state consistent
has been added to the -mm tree. Its filename is
exit-make-setting-exit_state-consistent.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/exit-make-setting-exit_state-consistent.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/exit-make-setting-exit_state-consistent.patch
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The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Christian Brauner <christian@xxxxxxxxxx>
Subject: exit: make setting exit_state consistent
Since commit b191d6491be6 ("pidfd: fix a poll race when setting
exit_state") we unconditionally set exit_state to EXIT_ZOMBIE before
calling into do_notify_parent().
This was done to eliminate a race when
querying exit_state in do_notify_pidfd(). Back then we decided to do the
absolute minimal thing to fix this and not touch the rest of the
exit_notify() function where exit_state is set.
Since this fix has not caused any issues change the setting of exit_state
to EXIT_DEAD in the autoreap case to account for the fact hat exit_state
is set to EXIT_ZOMBIE unconditionally. This fix was planned but also
explicitly requested in
https://lore.kernel.org/lkml/CAHk-=wigcxGFR2szue4wavJtH5cYTTeNES=toUBVGsmX0rzX+g@xxxxxxxxxxxxxx
and makes the whole code more consistent.
Link: http://lkml.kernel.org/r/20190729162757.22694-1-christian@xxxxxxxxxx
Signed-off-by: Christian Brauner <christian@xxxxxxxxxx>
Acked-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Prateek Sood <prsood@xxxxxxxxxxxxxx>
Cc: Andrei Vagin <avagin@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/exit.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/kernel/exit.c~exit-make-setting-exit_state-consistent
+++ a/kernel/exit.c
@@ -734,9 +734,10 @@ static void exit_notify(struct task_stru
autoreap = true;
}
- tsk->exit_state = autoreap ? EXIT_DEAD : EXIT_ZOMBIE;
- if (tsk->exit_state == EXIT_DEAD)
+ if (autoreap) {
+ tsk->exit_state = EXIT_DEAD;
list_add(&tsk->ptrace_entry, &dead);
+ }
/* mt-exec, de_thread() is waiting for group leader */
if (unlikely(tsk->signal->notify_count < 0))
_
Patches currently in -mm which might be from christian@xxxxxxxxxx are
exit-make-setting-exit_state-consistent.patch
