diff options
| -rw-r--r-- | Documentation/sysrq.txt | 2 | ||||
| -rw-r--r-- | drivers/char/sysrq.c | 46 |
2 files changed, 48 insertions, 0 deletions
diff --git a/Documentation/sysrq.txt b/Documentation/sysrq.txt index 10c8f6922ef..5ce0952aa06 100644 --- a/Documentation/sysrq.txt +++ b/Documentation/sysrq.txt @@ -85,6 +85,8 @@ On all - write a character to /proc/sysrq-trigger. e.g.: 'k' - Secure Access Key (SAK) Kills all programs on the current virtual console. NOTE: See important comments below in SAK section. +'l' - Shows a stack backtrace for all active CPUs. + 'm' - Will dump current memory info to your console. 'n' - Used to make RT tasks nice-able diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c index 1ade193c912..9e9bad8bdcf 100644 --- a/drivers/char/sysrq.c +++ b/drivers/char/sysrq.c @@ -196,6 +196,48 @@ static struct sysrq_key_op sysrq_showlocks_op = { #define sysrq_showlocks_op (*(struct sysrq_key_op *)0) #endif +#ifdef CONFIG_SMP +static DEFINE_SPINLOCK(show_lock); + +static void showacpu(void *dummy) +{ + unsigned long flags; + + /* Idle CPUs have no interesting backtrace. */ + if (idle_cpu(smp_processor_id())) + return; + + spin_lock_irqsave(&show_lock, flags); + printk(KERN_INFO "CPU%d:\n", smp_processor_id()); + show_stack(NULL, NULL); + spin_unlock_irqrestore(&show_lock, flags); +} + +static void sysrq_showregs_othercpus(struct work_struct *dummy) +{ + smp_call_function(showacpu, NULL, 0, 0); +} + +static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus); + +static void sysrq_handle_showallcpus(int key, struct tty_struct *tty) +{ + struct pt_regs *regs = get_irq_regs(); + if (regs) { + printk(KERN_INFO "CPU%d:\n", smp_processor_id()); + show_regs(regs); + } + schedule_work(&sysrq_showallcpus); +} + +static struct sysrq_key_op sysrq_showallcpus_op = { + .handler = sysrq_handle_showallcpus, + .help_msg = "aLlcpus", + .action_msg = "Show backtrace of all active CPUs", + .enable_mask = SYSRQ_ENABLE_DUMP, +}; +#endif + static void sysrq_handle_showregs(int key, struct tty_struct *tty) { struct pt_regs *regs = get_irq_regs(); @@ -340,7 +382,11 @@ static struct sysrq_key_op *sysrq_key_table[36] = { &sysrq_kill_op, /* i */ NULL, /* j */ &sysrq_SAK_op, /* k */ +#ifdef CONFIG_SMP + &sysrq_showallcpus_op, /* l */ +#else NULL, /* l */ +#endif &sysrq_showmem_op, /* m */ &sysrq_unrt_op, /* n */ /* o: This will often be registered as 'Off' at init time */ |