From: Eric Dumazet <edumazet@google.com>
Date: Sat, 8 Mar 2025 16:48:17 +0000 (+0100)
Subject: posix-timers: Add cond_resched() to posix_timer_add() search loop
X-Git-Tag: v6.14.9~583
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f69184971bfcdf8ed2399db844b78127129d288e;p=thirdparty%2Fkernel%2Fstable.git

posix-timers: Add cond_resched() to posix_timer_add() search loop

[ Upstream commit 5f2909c6cd13564a07ae692a95457f52295c4f22 ]

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@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/all/20250214135911.2037402-2-edumazet@google.com
Link: https://lore.kernel.org/all/20250308155623.635612865@linutronix.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index 1b675aee99a98..7f8644e047558 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -118,6 +118,7 @@ static int posix_timer_add(struct k_itimer *timer)
 			return id;
 		}
 		spin_unlock(&hash_lock);
+		cond_resched();
 	}
 	/* POSIX return code when no timer ID could be allocated */
 	return -EAGAIN;