diff options
| author | John Ogness <john.ogness@linutronix.de> | 2022-02-11 12:29:37 +0106 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2022-02-15 16:10:55 +0100 |
| commit | 2ba3673d70178bf07fb75ff25c54bc478add4021 (patch) | |
| tree | 5d56f38d31a066c307f00d41b46f96cb5212362f /kernel/printk | |
| parent | a229327733b86aa585effdb0d27a87b12aa51597 (diff) | |
printk: use atomic updates for klogd work
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
Diffstat (limited to 'kernel/printk')
| -rw-r--r-- | kernel/printk/printk.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 155229f0cf0f..25dce8b74791 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -3226,7 +3226,7 @@ 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 */ @@ -3260,7 +3260,7 @@ void defer_console_output(void) return; 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(); } |