diff options
| -rw-r--r-- | kernel/printk/printk.c | 22 |
1 files changed, 8 insertions, 14 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 3a475f58b749..6b9d8d56e0e2 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -1889,12 +1889,19 @@ asmlinkage int vprintk_emit(int facility, int level, /* If called from the scheduler, we can not call up(). */ if (!in_sched) { /* + * Disable preemption to avoid being preempted while holding + * console_sem which would prevent anyone from printing to + * console + */ + preempt_disable(); + /* * Try to acquire and then immediately release the console * semaphore. The release will print out buffers and wake up * /dev/kmsg and syslog() users. */ if (console_trylock_spinning()) console_unlock(); + preempt_enable(); } return printed_len; @@ -2211,20 +2218,7 @@ int console_trylock(void) return 0; } console_locked = 1; - /* - * When PREEMPT_COUNT disabled we can't reliably detect if it's - * safe to schedule (e.g. calling printk while holding a spin_lock), - * because preempt_disable()/preempt_enable() are just barriers there - * and preempt_count() is always 0. - * - * RCU read sections have a separate preemption counter when - * PREEMPT_RCU enabled thus we must take extra care and check - * rcu_preempt_depth(), otherwise RCU read sections modify - * preempt_count(). - */ - console_may_schedule = !oops_in_progress && - preemptible() && - !rcu_preempt_depth(); + console_may_schedule = 0; return 1; } EXPORT_SYMBOL(console_trylock); |