Messages in this thread Patch in this message | | | From | Mark Rutland <> | Subject | [PATCH v5 03/10] sched: snapshot thread flags | Date | Tue, 14 Sep 2021 11:30:20 +0100 |
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Some thread flags can be set remotely, and so even when IRQs are disabled, the flags can change under our feet. Generally this is unlikely to cause a problem in practice, but it is somewhat unsound, and KCSAN will legitimately warn that there is a data race.
To avoid such issues, a snapshot of the flags has to be taken prior to using them. Some places already use READ_ONCE() for that, others do not.
Convert them all to the new flag accessor helpers.
The READ_ONCE(ti->flags) .. cmpxchg(ti->flags) loop in set_nr_if_polling() is left as-is for clarity.
Signed-off-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Paul E. McKenney <paulmck@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Vincent Guittot <vincent.guittot@linaro.org> --- kernel/sched/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 1bba4128a3e6..b65876b5d64c 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -8538,7 +8538,7 @@ void sched_show_task(struct task_struct *p) rcu_read_unlock(); pr_cont(" stack:%5lu pid:%5d ppid:%6d flags:0x%08lx\n", free, task_pid_nr(p), ppid, - (unsigned long)task_thread_info(p)->flags); + read_task_thread_flags(p)); print_worker_info(KERN_INFO, p); print_stop_info(KERN_INFO, p); -- 2.11.0
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