From 6ce895128b3bff738fe8d9dd74747a03e319e466 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Mon, 29 Nov 2021 13:06:44 +0000 Subject: entry: Snapshot thread flags 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. Signed-off-by: Mark Rutland Signed-off-by: Thomas Gleixner Acked-by: Paul E. McKenney Link: https://lore.kernel.org/r/20211129130653.2037928-3-mark.rutland@arm.com --- kernel/entry/common.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/entry/common.c') diff --git a/kernel/entry/common.c b/kernel/entry/common.c index d5a61d565ad5..bad713684c2e 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -187,7 +187,7 @@ static unsigned long exit_to_user_mode_loop(struct pt_regs *regs, /* Check if any of the above work has queued a deferred wakeup */ tick_nohz_user_enter_prepare(); - ti_work = READ_ONCE(current_thread_info()->flags); + ti_work = read_thread_flags(); } /* Return the latest work state for arch_exit_to_user_mode() */ @@ -196,7 +196,7 @@ static unsigned long exit_to_user_mode_loop(struct pt_regs *regs, static void exit_to_user_mode_prepare(struct pt_regs *regs) { - unsigned long ti_work = READ_ONCE(current_thread_info()->flags); + unsigned long ti_work = read_thread_flags(); lockdep_assert_irqs_disabled(); -- cgit v1.2.3-70-g09d2