The patch titled
sysrq: add a show-stacktrace-on-all-cpus command
has been added to the -mm tree. Its filename is
sysrq-add-a-show-stacktrace-on-all-cpus-command.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: sysrq: add a show-stacktrace-on-all-cpus command
From: Avi Kivity <avi@xxxxxxxxxxxx>
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 <avi@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/char/sysrq.c | 24 +++++++++++++++++++++++-
1 files changed, 23 insertions(+), 1 deletion(-)
diff -puN drivers/char/sysrq.c~sysrq-add-a-show-stacktrace-on-all-cpus-command drivers/char/sysrq.c
--- a/drivers/char/sysrq.c~sysrq-add-a-show-stacktrace-on-all-cpus-command
+++ a/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_ta
&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 */
};
_
Patches currently in -mm which might be from avi@xxxxxxxxxxxx are
origin.patch
ia64-allow-smp_call_function_single-to-current-cpu.patch
git-kvm.patch
cpuid-driver-simplify-smp_call_function_single-call-sequence.patch
msr-driver-simplify-smp_call_function_single-call-sequence.patch
time-simplify-smp_call_function_single-call-sequence.patch
sysrq-add-a-show-stacktrace-on-all-cpus-command.patch
sysrq-add-a-show-stacktrace-on-all-cpus-command-fix.patch
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