sysrq: add show-backtrace-on-all-cpus function
SysRQ-P is not always useful on SMP systems, since it usually ends up showing
the backtrace of a CPU that is doing just fine, instead of the backtrace of
the CPU that is having problems.
This patch adds SysRQ show-all-cpus(L), which shows the backtrace of every
active CPU in the system. It skips idle CPUs because some SMP systems are
just too large and we already know what the backtrace of the idle task looks
like.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Rik van Riel <riel@redhat.com>
Randy Dunlap <randy.dunlap@oracle.com>
Cc: <lwoodman@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/sysrq.txt b/Documentation/sysrq.txt
index 10c8f69..5ce0952 100644
--- a/Documentation/sysrq.txt
+++ b/Documentation/sysrq.txt
@@ -85,6 +85,8 @@
'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