If a cpu is spinning in the kernel but still responding to interrupts, pressing sysrq-y will show you where it's spinning.
Signed-off-by: Avi Kivity <[EMAIL PROTECTED]> diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c index 39cc318..1dda709 100644 --- a/drivers/char/sysrq.c +++ b/drivers/char/sysrq.c @@ -45,6 +45,8 @@ int __read_mostly __sysrq_enabled = 1; static int __read_mostly sysrq_always_enabled; +static spinlock_t show_stack_lock = SPIN_LOCK_UNLOCKED; + int sysrq_on(void) { return __sysrq_enabled || sysrq_always_enabled; @@ -309,6 +311,26 @@ static struct sysrq_key_op sysrq_unrt_op = { .enable_mask = SYSRQ_ENABLE_RTNICE, }; +static void show_cpu_stack(void *garbage) +{ + spin_lock(&show_stack_lock); + printk("CPU%d stacktrace:\n", raw_smp_processor_id()); + dump_stack(); + sysrq_handle_showregs(0, NULL); + spin_unlock(&show_stack_lock); +} + +static void sysrq_show_stacks(int key, struct tty_struct *tty) +{ + on_each_cpu(show_cpu_stack, NULL, 0, 1); +} + +static struct sysrq_key_op sysrq_show_stacks_op = { + .handler = sysrq_show_stacks, + .help_msg = "stacktraces-on-all-cpus(Y)", + .action_msg = "Stack traces on all cpus", +}; + /* Key Operations table and lock */ static DEFINE_SPINLOCK(sysrq_key_table_lock); @@ -356,7 +378,7 @@ static struct sysrq_key_op *sysrq_key_table[36] = { &sysrq_showstate_blocked_op, /* w */ /* x: May be registered on ppc/powerpc for xmon */ NULL, /* x */ - NULL, /* y */ + &sysrq_show_stacks_op, /* y */ NULL /* z */ }; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/