debug lockups: Improve lockup detection, fix generic arch fallback

[pandora-kernel.git] / drivers / char / sysrq.c

diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c
index 0db3585..50eecfe 100644 (file)
--- a/drivers/char/sysrq.c
+++ b/drivers/char/sysrq.c
@@ -24,6 +24,7 @@
 #include <linux/sysrq.h>
 #include <linux/kbd_kern.h>
 #include <linux/proc_fs.h>
+#include <linux/nmi.h>
 #include <linux/quotaops.h>
 #include <linux/perf_counter.h>
 #include <linux/kernel.h>
@@ -35,7 +36,6 @@
 #include <linux/spinlock.h>
 #include <linux/vt_kern.h>
 #include <linux/workqueue.h>
-#include <linux/kexec.h>
 #include <linux/hrtimer.h>
 #include <linux/oom.h>
 
@@ -124,9 +124,12 @@ static struct sysrq_key_op sysrq_unraw_op = {
 static void sysrq_handle_crash(int key, struct tty_struct *tty)
 {
        char *killer = NULL;
+
+       panic_on_oops = 1;      /* force panic */
+       wmb();
        *killer = 1;
 }
-static struct sysrq_key_op sysrq_crashdump_op = {
+static struct sysrq_key_op sysrq_crash_op = {
        .handler        = sysrq_handle_crash,
        .help_msg       = "Crash",
        .action_msg     = "Trigger a crash",
@@ -220,12 +223,20 @@ 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);
+       /*
+        * Fall back to the workqueue based printing if the
+        * backtrace printing did not succeed or the
+        * architecture has no support for it:
+        */
+       if (!trigger_all_cpu_backtrace()) {
+               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);
        }
-       schedule_work(&sysrq_showallcpus);
 }
 
 static struct sysrq_key_op sysrq_showallcpus_op = {
@@ -401,7 +412,7 @@ static struct sysrq_key_op *sysrq_key_table[36] = {
         */
        NULL,                           /* a */
        &sysrq_reboot_op,               /* b */
-       &sysrq_crashdump_op,            /* c & ibm_emac driver debug */
+       &sysrq_crash_op,                /* c & ibm_emac driver debug */
        &sysrq_showlocks_op,            /* d */
        &sysrq_term_op,                 /* e */
        &sysrq_moom_op,                 /* f */