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Message-ID: <ec203c0e-13a9-4163-94dd-a8a8d6d2c070@kernel.dk>
Date: Wed, 12 Jun 2024 10:57:30 -0600
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Subject: Re: [PATCH] zap_pid_ns_processes: clear TIF_NOTIFY_SIGNAL along with
 TIF_SIGPENDING
To: Oleg Nesterov <oleg@redhat.com>, Andrew Morton
 <akpm@linux-foundation.org>, Rachel Menge <rachelmenge@linux.microsoft.com>
Cc: linux-kernel@vger.kernel.org, rcu@vger.kernel.org,
 Wei Fu <fuweid89@gmail.com>, apais@linux.microsoft.com,
 Sudhanva Huruli <Sudhanva.Huruli@microsoft.com>,
 Christian Brauner <brauner@kernel.org>,
 Mike Christie <michael.christie@oracle.com>,
 Joel Granados <j.granados@samsung.com>, Mateusz Guzik <mjguzik@gmail.com>,
 "Paul E. McKenney" <paulmck@kernel.org>,
 Frederic Weisbecker <frederic@kernel.org>,
 Neeraj Upadhyay <neeraj.upadhyay@kernel.org>,
 Joel Fernandes <joel@joelfernandes.org>,
 Josh Triplett <josh@joshtriplett.org>, Boqun Feng <boqun.feng@gmail.com>,
 Steven Rostedt <rostedt@goodmis.org>,
 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
 Lai Jiangshan <jiangshanlai@gmail.com>, Zqiang <qiang.zhang1211@gmail.com>
References: <1386cd49-36d0-4a5c-85e9-bc42056a5a38@linux.microsoft.com>
 <20240608120616.GB7947@redhat.com>
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From: Jens Axboe <axboe@kernel.dk>
In-Reply-To: <20240608120616.GB7947@redhat.com>
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On 6/8/24 6:06 AM, Oleg Nesterov wrote:
> kernel_wait4() doesn't sleep and returns -EINTR if there is no
> eligible child and signal_pending() is true.
> 
> That is why zap_pid_ns_processes() clears TIF_SIGPENDING but this is not
> enough, it should also clear TIF_NOTIFY_SIGNAL to make signal_pending()
> return false and avoid a busy-wait loop.

Reviewed-by: Jens Axboe <axboe@kernel.dk>

-- 
Jens Axboe