diff options
| -rw-r--r-- | drivers/tty/sysrq.c | 6 | ||||
| -rw-r--r-- | include/linux/printk.h | 2 | ||||
| -rw-r--r-- | kernel/panic.c | 3 | ||||
| -rw-r--r-- | kernel/printk/printk.c | 10 |
4 files changed, 21 insertions, 0 deletions
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c index 59e82e6d776d..573b2055173c 100644 --- a/drivers/tty/sysrq.c +++ b/drivers/tty/sysrq.c @@ -527,8 +527,12 @@ void __handle_sysrq(int key, bool check_mask) { struct sysrq_key_op *op_p; int orig_log_level; + int orig_suppress_printk; int i; + orig_suppress_printk = suppress_printk; + suppress_printk = 0; + rcu_sysrq_start(); rcu_read_lock(); /* @@ -574,6 +578,8 @@ void __handle_sysrq(int key, bool check_mask) } rcu_read_unlock(); rcu_sysrq_end(); + + suppress_printk = orig_suppress_printk; } void handle_sysrq(int key) diff --git a/include/linux/printk.h b/include/linux/printk.h index 84ea4d094af3..cefd374c47b1 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -82,6 +82,8 @@ static inline void console_verbose(void) extern char devkmsg_log_str[]; struct ctl_table; +extern int suppress_printk; + struct va_format { const char *fmt; va_list *va; diff --git a/kernel/panic.c b/kernel/panic.c index c1fcaad337b7..a6145050a8da 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -321,6 +321,9 @@ void panic(const char *fmt, ...) disabled_wait(); #endif pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf); + + /* Do not scroll important messages printed above */ + suppress_printk = 1; local_irq_enable(); for (i = 0; ; i += PANIC_TIMER_STEP) { touch_softlockup_watchdog(); diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 02ca827b8fac..17102fd4c136 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -86,6 +86,12 @@ static DEFINE_SEMAPHORE(console_sem); struct console *console_drivers; EXPORT_SYMBOL_GPL(console_drivers); +/* + * System may need to suppress printk message under certain + * circumstances, like after kernel panic happens. + */ +int __read_mostly suppress_printk; + #ifdef CONFIG_LOCKDEP static struct lockdep_map console_lock_dep_map = { .name = "console_lock" @@ -1943,6 +1949,10 @@ asmlinkage int vprintk_emit(int facility, int level, unsigned long flags; u64 curr_log_seq; + /* Suppress unimportant messages after panic happens */ + if (unlikely(suppress_printk)) + return 0; + if (level == LOGLEVEL_SCHED) { level = LOGLEVEL_DEFAULT; in_sched = true; |