The following commit has been merged into the timers/core branch of tip:
Commit-ID: 1d4199cbbe95efaba51304cfd844bd0ccd224e61
Gitweb: https://git.kernel.org/tip/1d4199cbbe95efaba51304cfd844bd0ccd224e61
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Wed, 30 Oct 2024 08:53:51 +01:00
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Thu, 31 Oct 2024 11:45:01 +01:00
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: 79f8b28e85f8 ("timers: Annotate possible non critical data race of next_expiry")
Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
Link: https://lore.kernel.org/all/87a5emyqk0.ffs@tglx
Closes: https://lore.kernel.org/oe-lkp/202410301205.ef8e9743-lkp@xxxxxxxxx
---
kernel/time/timer.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 02355b2..a283e52 100644
--- 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);
|