timers: Add missing READ_ONCE() in __run_timer_base()

__run_timer_base() checks base::next_expiry without holding base::lock. That can race with a remote CPU updating next_expiry under the lock. This is an intentional and harmless data race, but lacks a READ_ONCE(), so KCSAN complains about this. Add the missing READ_ONCE(). All other places are covered already. Fixes: 79f8b28 ("timers: Annotate possible non critical data race of next_expiry") Reported-by: kernel test robot <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Frederic Weisbecker <[email protected]> Link: https://lore.kernel.org/all/87a5emyqk0.ffs@tglx Closes: https://lore.kernel.org/oe-lkp/[email protected]
sedwards · Oct 31, 2024 · 1d4199c · 1d4199c
1 parent bf9a001
commit 1d4199c
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
@@ -2421,7 +2421,8 @@ static inline void __run_timers(struct timer_base *base)
 
 static void __run_timer_base(struct timer_base *base)
 {
-	if (time_before(jiffies, base->next_expiry))
+	/* Can race against a remote CPU updating next_expiry under the lock */
+	if (time_before(jiffies, READ_ONCE(base->next_expiry)))
 		return;
 
 	timer_base_lock_expiry(base);