From: Oleg Nesterov <oleg@redhat.com>
To: Wei Fu <fuweid89@gmail.com>
Cc: ebiederm@xmission.com, Sudhanva.Huruli@microsoft.com,
akpm@linux-foundation.org, apais@linux.microsoft.com,
axboe@kernel.dk, boqun.feng@gmail.com, brauner@kernel.org,
frederic@kernel.org, j.granados@samsung.com,
jiangshanlai@gmail.com, joel@joelfernandes.org,
josh@joshtriplett.org, linux-kernel@vger.kernel.org,
mathieu.desnoyers@efficios.com, michael.christie@oracle.com,
mjguzik@gmail.com, neeraj.upadhyay@kernel.org,
paulmck@kernel.org, qiang.zhang1211@gmail.com,
rachelmenge@linux.microsoft.com, rcu@vger.kernel.org,
rostedt@goodmis.org
Subject: Re: [PATCH] zap_pid_ns_processes: clear TIF_NOTIFY_SIGNAL along with TIF_SIGPENDING
Date: Thu, 13 Jun 2024 16:49:13 +0200 [thread overview]
Message-ID: <20240613144913.GA18218@redhat.com> (raw)
In-Reply-To: <20240613140216.30327-1-fuweid89@gmail.com>
On 06/13, Wei Fu wrote:
>
> I think there is a case that TIF_NOTIFY_SIGNAL remains set.
[...snip...]
Of course! but please forget about io_uring even if currently io_uring/
is the only user of TWA_SIGNAL.
Just suppose that the exiting task/thread races with task_workd_add(TWA_SIGNAL),
TIF_NOTIFY_SIGNAL won't be cleared.
This is fine in that the exiting task T will do exit_task_work() and after that
task_work_add(T) can't succeed with or without TWA_SIGNAL. So it can't miss the
pending work.
But I think we can forget about TIF_NOTIFY_SIGNAL. To me, the problem is that
the state of signal_pending() of the exiting task was never clearly defined, and
I can't even recall how many times I mentioned this in the previous discussions.
TIF_NOTIFY_SIGNAL doesn't add more confusion, imo.
Oleg.
next prev parent reply other threads:[~2024-06-13 14:51 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-05 23:42 [RCU] zombie task hung in synchronize_rcu_expedited Rachel Menge
2024-06-06 11:10 ` Oleg Nesterov
2024-06-06 15:45 ` Wei Fu
2024-06-06 17:28 ` Oleg Nesterov
2024-06-07 3:02 ` Wei Fu
2024-06-07 6:25 ` Oleg Nesterov
2024-06-07 15:04 ` Wei Fu
2024-06-07 21:22 ` Oleg Nesterov
2024-06-08 12:42 ` Oleg Nesterov
2024-06-10 0:07 ` Wei Fu
2024-06-08 12:06 ` [PATCH] zap_pid_ns_processes: clear TIF_NOTIFY_SIGNAL along with TIF_SIGPENDING Oleg Nesterov
2024-06-08 17:00 ` Boqun Feng
2024-06-09 14:12 ` Wei Fu
2024-06-12 16:57 ` Jens Axboe
2024-06-13 12:40 ` Eric W. Biederman
2024-06-13 14:02 ` Wei Fu
2024-06-13 14:49 ` Oleg Nesterov [this message]
2024-06-13 15:30 ` Oleg Nesterov
2024-06-08 15:48 ` [PATCH] zap_pid_ns_processes: don't send SIGKILL to sub-threads Oleg Nesterov
2024-06-13 13:01 ` Eric W. Biederman
2024-06-13 15:00 ` Oleg Nesterov
2024-06-13 16:23 ` Eric W. Biederman
2024-07-05 16:08 ` Oleg Nesterov
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