From: Mark Rutland mark.rutland@arm.com
mainline inclusion from mainline-v5.17-rc1 commit 0569b245132c40015281610353935a50e282eb94 category: performance bugzilla: https://gitee.com/openeuler/kernel/issues/IA5WFA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
----------------------------------------------------------------------
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 Signed-off-by: Thomas Gleixner tglx@linutronix.de Acked-by: Paul E. McKenney paulmck@kernel.org Cc: Juri Lelli juri.lelli@redhat.com Cc: Vincent Guittot vincent.guittot@linaro.org Link: https://lore.kernel.org/r/20211129130653.2037928-4-mark.rutland@arm.com
Conflict: kernel/sched/core.c
Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- 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 557b01680ae7..770d3e7ace4f 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7613,7 +7613,7 @@ 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); show_stack(p, NULL, KERN_INFO);