[PATCH v2] kmsg_dump: Dump on crash_kexec as well

From: KOSAKI Motohiro
Date: Mon Dec 21 2009 - 22:15:53 EST


David, can you please pick this patch into your tree?

======================
crash_kexec gets called before kmsg_dump(KMSG_DUMP_OOPS) if
panic_on_oops is set, so the kernel log buffer is not stored
for this case.

This patch adds a KMSG_DUMP_KEXEC dump type which gets called
when crash_kexec() is invoked. To avoid getting double dumps,
the old KMSG_DUMP_PANIC is moved below crash_kexec(). The
mtdoops driver is modified to handle KMSG_DUMP_KEXEC in the
same way as a panic.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Acked-by: Simon Kagstrom <simon.kagstrom@xxxxxxxxxxxxxx>
Cc: Anders Grafstrom <anders.grafstrom@xxxxxxxxxxxxxx>
Cc: Artem Bityutskiy <Artem.Bityutskiy@xxxxxxxxx>
Cc: David Woodhouse <David.Woodhouse@xxxxxxxxx>
---
drivers/mtd/mtdoops.c | 2 +-
include/linux/kmsg_dump.h | 1 +
kernel/kexec.c | 4 ++++
kernel/panic.c | 3 ++-
kernel/printk.c | 1 +
5 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c
index a714ec4..92e12df 100644
--- a/drivers/mtd/mtdoops.c
+++ b/drivers/mtd/mtdoops.c
@@ -322,7 +322,7 @@ static void mtdoops_do_dump(struct kmsg_dumper *dumper,
memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy);

/* Panics must be written immediately */
- if (reason == KMSG_DUMP_PANIC) {
+ if (reason != KMSG_DUMP_OOPS) {
if (!cxt->mtd->panic_write)
printk(KERN_ERR "mtdoops: Cannot write from panic without panic_write\n");
else
diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h
index e32aa26..24b4414 100644
--- a/include/linux/kmsg_dump.h
+++ b/include/linux/kmsg_dump.h
@@ -17,6 +17,7 @@
enum kmsg_dump_reason {
KMSG_DUMP_OOPS,
KMSG_DUMP_PANIC,
+ KMSG_DUMP_KEXEC,
};

/**
diff --git a/kernel/kexec.c b/kernel/kexec.c
index a9a93d9..ef077fb 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -32,6 +32,7 @@
#include <linux/console.h>
#include <linux/vmalloc.h>
#include <linux/swap.h>
+#include <linux/kmsg_dump.h>

#include <asm/page.h>
#include <asm/uaccess.h>
@@ -1074,6 +1075,9 @@ void crash_kexec(struct pt_regs *regs)
if (mutex_trylock(&kexec_mutex)) {
if (kexec_crash_image) {
struct pt_regs fixed_regs;
+
+ kmsg_dump(KMSG_DUMP_KEXEC);
+
crash_setup_regs(&fixed_regs, regs);
crash_save_vmcoreinfo();
machine_crash_shutdown(&fixed_regs);
diff --git a/kernel/panic.c b/kernel/panic.c
index 5827f7b..c787333 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -75,7 +75,6 @@ NORET_TYPE void panic(const char * fmt, ...)
dump_stack();
#endif

- kmsg_dump(KMSG_DUMP_PANIC);
/*
* If we have crashed and we have a crash kernel loaded let it handle
* everything else.
@@ -83,6 +82,8 @@ NORET_TYPE void panic(const char * fmt, ...)
*/
crash_kexec(NULL);

+ kmsg_dump(KMSG_DUMP_PANIC);
+
/*
* Note smp_send_stop is the usual smp shutdown function, which
* unfortunately means it may not be hardened to work in a panic
diff --git a/kernel/printk.c b/kernel/printk.c
index 17463ca..1751c45 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -1467,6 +1467,7 @@ EXPORT_SYMBOL_GPL(kmsg_dump_unregister);
static const char const *kmsg_reasons[] = {
[KMSG_DUMP_OOPS] = "oops",
[KMSG_DUMP_PANIC] = "panic",
+ [KMSG_DUMP_KEXEC] = "kexec",
};

static const char *kmsg_to_str(enum kmsg_dump_reason reason)
--
1.6.5.2





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