Hi,
This patch removes a function call chain of kmsg_dump and mutex_lock of pstore from panic path
so that both pstore and APEI storage backend can work reliably in panic path.
kernel/kexec.c
- Move kmsg_dump(KMSG_DUMP_PANIC) behind machine_crash_shutdown() so that pstore can
work with one cpu.
fs/pstore/platform.c
pstore_dump()
- Remove mutex_lock from panic path
kernel/printk.c
- Add spin_lock_init(&logbuf) for avoiding dead lock in panic path
TODO:
APEI storage backend will work with this patch.
However, I don't have any access to servers capable of APEI storage backend.
Please help to test my patch.
Signed-off-by: Seiji Aguchi <seiji.aguchi at hds.com>
---
fs/pstore/platform.c | 3 ++-
kernel/panic.c | 4 ++--
2 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c index 85e0a9c..061911c 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -75,6 +75,7 @@ static void pstore_dump(struct kmsg_dumper *dumper,
why = "Unknown";
switch (reason) {
+ case KMSG_DUMP_PANIC:
case KMSG_DUMP_KEXEC:
/* Skip if there is no driver or there is a driver calling
pstore_register() */
@@ -114,7 +115,7 @@ static void pstore_dump(struct kmsg_dumper *dumper,
total += l1_cpy + l2_cpy;
}
- if (reason != KMSG_DUMP_KEXEC)
+ if (reason != KMSG_DUMP_PANIC && reason != KMSG_DUMP_KEXEC)
mutex_unlock(&psinfo->buf_mutex);
}
diff --git a/kernel/panic.c b/kernel/panic.c index 6923167..a9dce52 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -11,6 +11,7 @@
#include <linux/debug_locks.h>
#include <linux/interrupt.h>
#include <linux/kmsg_dump.h>
+#include <linux/pstore.h>
#include <linux/kallsyms.h>
#include <linux/notifier.h>
#include <linux/module.h>
@@ -88,14 +89,13 @@ 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
* situation.
*/
smp_send_stop();
+ pstore_kmsg_dump_in_interrupt(KMSG_DUMP_PANIC);
atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
--
1.7.1
