6.12-stable review patch. If anyone has any objections, please let me know.
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From: Thomas Gleixner tglx@linutronix.de
[ Upstream commit 1d4199cbbe95efaba51304cfd844bd0ccd224e61 ]
__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@intel.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Reviewed-by: Frederic Weisbecker frederic@kernel.org Link: https://lore.kernel.org/all/87a5emyqk0.ffs@tglx Closes: https://lore.kernel.org/oe-lkp/202410301205.ef8e9743-lkp@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 0fc9d066a7be4..7835f9b376e76 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -2422,7 +2422,8 @@ 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);