It is very useful to provide some means to force the kernel logs to make it out
via the kmsg_oops implementations on the console. Add a new option 'Y' to
sysrq to allow dumping of logs to kmsg_dumper drivers.
Signed-off-by: Mike Waychison <mikew@xxxxxxxxxx>
---
Changelog:
- v3
- Added a note to Documentation/sysrq.txt about the command.
TODO: Figure out a better letter? Can we reuse 'v'?
---
Documentation/sysrq.txt | 4 ++++
drivers/tty/sysrq.c | 14 +++++++++++++-
2 files changed, 17 insertions(+), 1 deletions(-)
diff --git a/Documentation/sysrq.txt b/Documentation/sysrq.txt
index 312e375..3c7ee87 100644
--- a/Documentation/sysrq.txt
+++ b/Documentation/sysrq.txt
@@ -118,6 +118,10 @@ On all - write a character to /proc/sysrq-trigger. e.g.:
'x' - Used by xmon interface on ppc/powerpc platforms.
'y' - Show global CPU Registers [SPARC-64 specific]
+'y' - Trigger a 'soft' kmsg dump. Any kmsg_dump clients (mtdoops,
+ netoops, ramoops) will initiate a dump to their respective
+ backend.
+
'z' - Dump the ftrace buffer
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index c556ed9..f79f34a 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -41,6 +41,7 @@
#include <linux/oom.h>
#include <linux/slab.h>
#include <linux/input.h>
+#include <linux/kmsg_dump.h>
#include <asm/ptrace.h>
#include <asm/irq_regs.h>
@@ -395,6 +396,17 @@ static struct sysrq_key_op sysrq_unrt_op = {
.enable_mask = SYSRQ_ENABLE_RTNICE,
};
+static void sysrq_handle_softdump(int key)
+{
+ kmsg_dump(KMSG_DUMP_SOFT, NULL);
+}
+static struct sysrq_key_op sysrq_softdump_op = {
+ .handler = sysrq_handle_softdump,
+ .help_msg = "soft-dump(Y)",
+ .action_msg = "Trigger a soft dump",
+ .enable_mask = SYSRQ_ENABLE_DUMP,
+};
+
/* Key Operations table and lock */
static DEFINE_SPINLOCK(sysrq_key_table_lock);
@@ -451,7 +463,7 @@ static struct sysrq_key_op *sysrq_key_table[36] = {
/* x: May be registered on ppc/powerpc for xmon */
NULL, /* x */
/* y: May be registered on sparc64 for global register dump */
- NULL, /* y */
+ &sysrq_softdump_op, /* y */
&sysrq_ftrace_dump_op, /* z */
};
--
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