kmsg_dump: Dump on crash_kexec as well

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@jp.fujitsu.com>
Acked-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

5 files changed, 9 insertions, 2 deletions

diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c
index a714ec482761..92e12df0917f 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 e32aa268efac..24b44145a886 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 433e9fcc1fc5..ae217488fef8 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 5827f7b97254..c787333282b8 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 1ded8e7dd19b..2c9dc0b03a5e 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)