On Mon, 8 Nov 2010 14:27:59 -0800 Mike Waychison wrote:

On Mon, Nov 8, 2010 at 1:09 PM, Randy Dunlap [off-list ref] wrote:

quoted

On Mon, 08 Nov 2010 12:33:23 -0800 Mike Waychison wrote:

quoted

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 <redacted>

Hi,

Please add 'y' to Documentation/sysrq.txt .

Ok.

Looking at the docs though, sparc64 has 'y' mapped to "Show global CPU
Registers".  The only slot available is 'a' if the list is up to date.

'a' has a big fat warning not to use it.
'x' is powerpc-specific, just as 'y' is sparc64 specific.

DaveM, any comments/suggestions on these?

Looks like one day soon we'll have to make a way to allow more sysrq keys...

An alternative may be to overload 'v' "Forcefully restores framebuffer
console" and "Causes ETM buffer dump [ARM-specific]" as these actions
seem to be about making crash data visible.

quoted

quoted

---
 drivers/char/sysrq.c |   14 +++++++++++++-
 1 files changed, 13 insertions(+), 1 deletions(-)

diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c
index eaa5d3e..058d3c8 100644
--- a/drivers/char/sysrq.c
+++ b/drivers/char/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 */
 };

---
~Randy
*** Remember to use Documentation/SubmitChecklist when testing your code ***

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---
~Randy
*** Remember to use Documentation/SubmitChecklist when testing your code ***