From: John Ogness john.ogness@linutronix.de
[ Upstream commit 2ba3673d70178bf07fb75ff25c54bc478add4021 ]
The per-cpu @printk_pending variable can be updated from sleepable contexts, such as:
get_random_bytes() warn_unseeded_randomness() printk_deferred() defer_console_output()
and can be updated from interrupt contexts, such as:
handle_irq_event_percpu() __irq_wake_thread() wake_up_process() try_to_wake_up() select_task_rq() select_fallback_rq() printk_deferred() defer_console_output()
and can be updated from NMI contexts, such as:
vprintk() if (in_nmi()) defer_console_output()
Therefore the atomic variant of the updating functions must be used.
Replace __this_cpu_xchg() with this_cpu_xchg(). Replace __this_cpu_or() with this_cpu_or().
Reported-by: Sebastian Andrzej Siewior bigeasy@linutronix.de Signed-off-by: John Ogness john.ogness@linutronix.de Signed-off-by: Petr Mladek pmladek@suse.com Link: https://lore.kernel.org/r/87iltld4ue.fsf@jogness.linutronix.de Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/printk/printk.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 1d7325f09004..8ec99b643a5a 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -2874,7 +2874,7 @@ static DEFINE_PER_CPU(int, printk_pending);
static void wake_up_klogd_work_func(struct irq_work *irq_work) { - int pending = __this_cpu_xchg(printk_pending, 0); + int pending = this_cpu_xchg(printk_pending, 0);
if (pending & PRINTK_PENDING_OUTPUT) { /* If trylock fails, someone else is doing the printing */ @@ -2904,7 +2904,7 @@ void wake_up_klogd(void) void defer_console_output(void) { preempt_disable(); - __this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT); + this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT); irq_work_queue(this_cpu_ptr(&wake_up_klogd_work)); preempt_enable(); }