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Message-ID: <20240613144913.GA18218@redhat.com>
Date: Thu, 13 Jun 2024 16:49:13 +0200
From: Oleg Nesterov <oleg@...hat.com>
To: Wei Fu <fuweid89@...il.com>
Cc: ebiederm@...ssion.com, Sudhanva.Huruli@...rosoft.com,
akpm@...ux-foundation.org, apais@...ux.microsoft.com,
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neeraj.upadhyay@...nel.org, paulmck@...nel.org,
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Subject: Re: [PATCH] zap_pid_ns_processes: clear TIF_NOTIFY_SIGNAL along with
TIF_SIGPENDING
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.
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