Commit ff7f6c2d authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Chen Ridong
Browse files

zap_pid_ns_processes: clear TIF_NOTIFY_SIGNAL along with TIF_SIGPENDING 

stable inclusion
from stable-v5.10.221
commit 82c7acf9a12c9b4e4b0aba531de82b4e39a345c8
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IAOPW2

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=82c7acf9a12c9b4e4b0aba531de82b4e39a345c8

--------------------------------

[ Upstream commit 7fea700e04bd3f424c2d836e98425782f97b494e ]

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.

Link: https://lkml.kernel.org/r/20240608120616.GB7947@redhat.com


Fixes: 12db8b69 ("entry: Add support for TIF_NOTIFY_SIGNAL")
Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Reported-by: default avatarRachel Menge <rachelmenge@linux.microsoft.com>
Closes: https://lore.kernel.org/all/1386cd49-36d0-4a5c-85e9-bc42056a5a38@linux.microsoft.com/


Reviewed-by: default avatarBoqun Feng <boqun.feng@gmail.com>
Tested-by: default avatarWei Fu <fuweid89@gmail.com>
Reviewed-by: default avatarJens Axboe <axboe@kernel.dk>
Cc: Allen Pais <apais@linux.microsoft.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Joel Granados <j.granados@samsung.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mike Christie <michael.christie@oracle.com>
Cc: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Zqiang <qiang.zhang1211@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
Signed-off-by: default avatarWang Hai <wanghai38@huawei.com>
Signed-off-by: default avatarChen Ridong <chenridong@huawei.com>
parent ea15a1c6

kernel/pid_namespace.c

+1 −0
Original line number Diff line number Diff line
@@ -222,6 +222,7 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns) 
	 */

	do {

		clear_thread_flag(TIF_SIGPENDING);

		clear_thread_flag(TIF_NOTIFY_SIGNAL);

		rc = kernel_wait4(-1, NULL, __WALL, NULL);

	} while (rc != -ECHILD);