diff options
| -rw-r--r-- | Documentation/sysctl/kernel.txt | 8 | ||||
| -rw-r--r-- | include/linux/kernel.h | 2 | ||||
| -rw-r--r-- | kernel/printk.c | 15 | ||||
| -rw-r--r-- | kernel/sysctl.c | 14 |
4 files changed, 39 insertions, 0 deletions
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index 3e5b63ebb821..b3d8b4922740 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -313,6 +313,14 @@ send before ratelimiting kicks in. ============================================================== +printk_delay: + +Delay each printk message in printk_delay milliseconds + +Value from 0 - 10000 is allowed. + +============================================================== + randomize-va-space: This option can be used to select the type of process address diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 2b5b1e0899a8..0a2a19087863 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -246,6 +246,8 @@ extern int printk_ratelimit(void); extern bool printk_timed_ratelimit(unsigned long *caller_jiffies, unsigned int interval_msec); +extern int printk_delay_msec; + /* * Print a one-time message (analogous to WARN_ONCE() et al): */ diff --git a/kernel/printk.c b/kernel/printk.c index 932ea21feb18..f38b07f78a4e 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -653,6 +653,20 @@ static int recursion_bug; static int new_text_line = 1; static char printk_buf[1024]; +int printk_delay_msec __read_mostly; + +static inline void printk_delay(void) +{ + if (unlikely(printk_delay_msec)) { + int m = printk_delay_msec; + + while (m--) { + mdelay(1); + touch_nmi_watchdog(); + } + } +} + asmlinkage int vprintk(const char *fmt, va_list args) { int printed_len = 0; @@ -662,6 +676,7 @@ asmlinkage int vprintk(const char *fmt, va_list args) char *p; boot_delay_msec(); + printk_delay(); preempt_disable(); /* This stops the holder of console_sem just where we want him */ diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 6ba49c7cb128..0dfaa47d7cb6 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -106,6 +106,9 @@ static int __maybe_unused one = 1; static int __maybe_unused two = 2; static unsigned long one_ul = 1; static int one_hundred = 100; +#ifdef CONFIG_PRINTK +static int ten_thousand = 10000; +#endif /* this is needed for the proc_doulongvec_minmax of vm_dirty_bytes */ static unsigned long dirty_bytes_min = 2 * PAGE_SIZE; @@ -722,6 +725,17 @@ static struct ctl_table kern_table[] = { .mode = 0644, .proc_handler = &proc_dointvec, }, + { + .ctl_name = CTL_UNNUMBERED, + .procname = "printk_delay", + .data = &printk_delay_msec, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = &proc_dointvec_minmax, + .strategy = &sysctl_intvec, + .extra1 = &zero, + .extra2 = &ten_thousand, + }, #endif { .ctl_name = KERN_NGROUPS_MAX, |