linux-kernel - [patch 02/11] posix-timers: Add cond_resched() to posix_timer

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Message-ID: <20250224101343.078382991@linutronix.de>
Date: Mon, 24 Feb 2025 11:15:25 +0100 (CET)
From: Thomas Gleixner <tglx@...utronix.de>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Anna-Maria Behnsen <anna-maria@...utronix.de>,
 Frederic Weisbecker <frederic@...nel.org>,
 Benjamin Segall <bsegall@...gle.com>,
 Eric Dumazet <edumazet@...gle.com>,
 Andrey Vagin <avagin@...nvz.org>,
 Pavel Tikhomirov <ptikhomirov@...tuozzo.com>,
 Peter Zijlstra <peterz@...radead.org>
Subject: [patch 02/11] posix-timers: Add cond_resched() to posix_timer_add()
 search loop

From: Eric Dumazet <edumazet@...gle.com>

With a large number of POSIX timers the search for a valid ID might cause a
soft lockup on PREEMPT_NONE/VOLUNTARY kernels.

Add cond_resched() to the loop to prevent that.

[ tglx: Split out from Eric's series ]

Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Link: https://lore.kernel.org/all/20250214135911.2037402-2-edumazet@google.com
---
 kernel/time/posix-timers.c |    1 +
 1 file changed, 1 insertion(+)

--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -144,6 +144,7 @@ static int posix_timer_add(struct k_itim
 			return id;
 		}
 		spin_unlock(&hash_lock);
+		cond_resched();
 	}
 	/* POSIX return code when no timer ID could be allocated */
 	return -EAGAIN;