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Message-ID: <20240205141348.GA16539@redhat.com>
Date: Mon, 5 Feb 2024 15:13:48 +0100
From: Oleg Nesterov <oleg@...hat.com>
To: Christian Brauner <brauner@...nel.org>
Cc: Andy Lutomirski <luto@...capital.net>,
"Eric W. Biederman" <ebiederm@...ssion.com>,
Tycho Andersen <tycho@...ho.pizza>, linux-kernel@...r.kernel.org
Subject: [PATCH] pidfd: change do_notify_pidfd() to use
__wake_up(poll_to_key(EPOLLIN))
rather than wake_up_all(). This way do_notify_pidfd() won't wakeup the
POLLHUP-only waiters which wait for pid_task() == NULL.
TODO:
- as Christian pointed out, this asks for the new wake_up_all_poll()
helper, it can already have other users.
- we can probably discriminate the PIDFD_THREAD and non-PIDFD_THREAD
waiters, but this needs more work. See
https://lore.kernel.org/all/20240205140848.GA15853@redhat.com/
Signed-off-by: Oleg Nesterov <oleg@...hat.com>
---
kernel/signal.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/kernel/signal.c b/kernel/signal.c
index 9b40109f0c56..c3fac06937e2 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2021,11 +2021,12 @@ int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
void do_notify_pidfd(struct task_struct *task)
{
- struct pid *pid;
+ struct pid *pid = task_pid(task);
WARN_ON(task->exit_state == 0);
- pid = task_pid(task);
- wake_up_all(&pid->wait_pidfd);
+
+ __wake_up(&pid->wait_pidfd, TASK_NORMAL, 0,
+ poll_to_key(EPOLLIN | EPOLLRDNORM));
}
/*
--
2.25.1.362.g51ebf55
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