um: add a kmsg_dumper
Add a kmsg_dumper, that dumps the kmsg buffer to stdout, when no console
is available. This an enables the printing of early panic() calls
triggered in uml_postsetup().
When a panic() call happens so early in the UML kernel no
earlyprintk/console is available yet, but with a kmsg_dumper in place
the kernel message buffer will be outputted to the user, to give a
better hint, of what the failure was.
Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 9b06957..926ecdc 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -11,6 +11,7 @@
#include <linux/string.h>
#include <linux/utsname.h>
#include <linux/sched.h>
+#include <linux/kmsg_dump.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
#include <asm/sections.h>
@@ -211,6 +212,7 @@
static int panic_exit(struct notifier_block *self, unsigned long unused1,
void *unused2)
{
+ kmsg_dump(KMSG_DUMP_PANIC);
bust_spinlocks(1);
bust_spinlocks(0);
uml_exitcode = 1;