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authorCarsten Emde <C.Emde@osadl.org>2011-07-19 13:51:17 +0100
committerClark Williams <williams@redhat.com>2012-04-13 11:01:51 -0500
commitae619e9b7cbc0d368015b6abd357fdcfa4cb094f (patch)
treefe771fa85bc0c81c018671ec8229e4b44925fa2c /Documentation
parent10153f0f0fa48334a151a4851a7094a4f9f328d8 (diff)
ping-sysrq.patch
There are (probably rare) situations when a system crashed and the system console becomes unresponsive but the network icmp layer still is alive. Wouldn't it be wonderful, if we then could submit a sysreq command via ping? This patch provides this facility. Please consult the updated documentation Documentation/sysrq.txt for details. Signed-off-by: Carsten Emde <C.Emde@osadl.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/sysrq.txt11
1 files changed, 9 insertions, 2 deletions
diff --git a/Documentation/sysrq.txt b/Documentation/sysrq.txt
index 642f84495b29..bd283ede08d3 100644
--- a/Documentation/sysrq.txt
+++ b/Documentation/sysrq.txt
@@ -57,10 +57,17 @@ On PowerPC - Press 'ALT - Print Screen (or F13) - <command key>,
On other - If you know of the key combos for other architectures, please
let me know so I can add them to this section.
-On all - write a character to /proc/sysrq-trigger. e.g.:
-
+On all - write a character to /proc/sysrq-trigger, e.g.:
echo t > /proc/sysrq-trigger
+On all - Enable network SysRq by writing a cookie to icmp_echo_sysrq, e.g.
+ echo 0x01020304 >/proc/sys/net/ipv4/icmp_echo_sysrq
+ Send an ICMP echo request with this pattern plus the particular
+ SysRq command key. Example:
+ # ping -c1 -s57 -p0102030468
+ will trigger the SysRq-H (help) command.
+
+
* What are the 'command' keys?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
'b' - Will immediately reboot the system without syncing or unmounting