From: Christian Brauner christian@brauner.io
[ Upstream commit 30b692d3b390c6fe78a5064be0c4bbd44a41be59 ]
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 [1] and makes the whole code more consistent.
/* References */ [1]: https://lore.kernel.org/lkml/CAHk-=wigcxGFR2szue4wavJtH5cYTTeNES=toUBVGsmX0r...
Signed-off-by: Christian Brauner christian@brauner.io Acked-by: Oleg Nesterov oleg@redhat.com Cc: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/exit.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/exit.c b/kernel/exit.c index 03f6722302b54..14c2f0717ee4b 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -619,9 +619,10 @@ static void exit_notify(struct task_struct *tsk, int group_dead) 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))