diff options
| -rw-r--r-- | kernel/printk/printk.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index f717656c0fac..e9a7e50ed60a 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -1890,8 +1890,9 @@ asmlinkage int vprintk_emit(int facility, int level, const char *fmt, va_list args) { int printed_len; - bool in_sched = false; + bool in_sched = false, pending_output; unsigned long flags; + u64 curr_log_seq; if (level == LOGLEVEL_SCHED) { level = LOGLEVEL_DEFAULT; @@ -1903,11 +1904,13 @@ asmlinkage int vprintk_emit(int facility, int level, /* This stops the holder of console_sem just where we want him */ logbuf_lock_irqsave(flags); + curr_log_seq = log_next_seq; printed_len = vprintk_store(facility, level, dict, dictlen, fmt, args); + pending_output = (curr_log_seq != log_next_seq); logbuf_unlock_irqrestore(flags); /* If called from the scheduler, we can not call up(). */ - if (!in_sched) { + if (!in_sched && pending_output) { /* * Disable preemption to avoid being preempted while holding * console_sem which would prevent anyone from printing to @@ -1924,7 +1927,8 @@ asmlinkage int vprintk_emit(int facility, int level, preempt_enable(); } - wake_up_klogd(); + if (pending_output) + wake_up_klogd(); return printed_len; } EXPORT_SYMBOL(vprintk_emit); |