On Tue, 23 May 2023 at 02:42, Tejun Heo tj@kernel.org wrote:
On Mon, May 22, 2023 at 08:20:38AM -1000, Tejun Heo wrote:
Hello,
On Mon, May 22, 2023 at 09:24:09PM +0800, Z qiang wrote:
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 9c5c1cfa478f..f8d739fef311 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1060,10 +1060,9 @@ void wq_worker_running(struct task_struct *task) * and leave with an unexpected pool->nr_running == 1 on the newly unbound * pool. Protect against such race. */
preempt_disable();
local_irq_disable(); if (!(worker->flags & WORKER_NOT_RUNNING)) worker->pool->nr_running++;
preempt_enable(); /* * CPU intensive auto-detection cares about how long a work item
hogged @@ -1072,6 +1071,7 @@ void wq_worker_running(struct task_struct *task) worker->current_at = worker->task->se.sum_exec_runtime;
worker->sleeping = 0;
local_irq_enable();
}
Ah, yeah, this is correct. Now we're modifying nr_running from timer tick too, so if don't block irq, the timer tick can ruin the not-irq-protected read-write-modify nr_running update from wq_worker_running(). Naresh, can you please confirm the fix?
Z qiang, while waiting for Naresh's test result, can you send the fix as a proper signed-off-patch?
The proposed patch applied on top of Linux next and boot tested for more than 100 times and is still running in a loop by Anders.
The reported warning did not reproduce again.
Tested-by: Anders Roxell anders.roxell@linaro.org Reported-by: Linux Kernel Functional Testing lkft@linaro.org
- Naresh
Thanks.
-- tejun