On 12/04/26 17:00, Shivang Upadhyay wrote:
fadump is registered in panic_notifier_list and gets triggered before
kmsg_dump_desc() in the panic path. As a result, kmsg_dumpers such as
pstore are not executed during fadump crashes.
This is problematic because pstore provides a critical fallback mechanism
for crash analysis. When fadump fails to successfully reboot the system
or capture a dump, pstore logs may be the only available information from
the crashed kernel. Without invoking kmsg_dump_desc() in the fadump path,
we lose this valuable diagnostic data.
Invoke kmsg_dump_desc() from the fadump panic handler, but only when
fadump is actually registered (checked via should_fadump_crash()). This
ensures kmsg_dumpers are called without duplicating the call that occurs
later in panic() when fadump is not active.
The call is placed before crash_fadump() to ensure logs are captured
before the system attempts to trigger the firmware-assisted dump.
Cc: Hari Bathini <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Mahesh Salgaonkar <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Ritesh Harjani (IBM) <[email protected]>
Reported-by: Shirisha G <[email protected]>
Suggested-by: Sourabh Jain <[email protected]>
Signed-off-by: Shivang Upadhyay <[email protected]>
---
Changelog:
v2:
address comments from Sourabh, and sashikio-ai
added should_fadump_crash()
v1:
https://lore.kernel.org/all/[email protected]/
---
arch/powerpc/kernel/setup-common.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/arch/powerpc/kernel/setup-common.c
b/arch/powerpc/kernel/setup-common.c
index b1761909c23f..87afc8003a03 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -68,6 +68,7 @@
#include <asm/kasan.h>
#include <asm/mce.h>
#include <asm/systemcfg.h>
+#include <linux/kmsg_dump.h>
#include "setup.h"
@@ -744,6 +745,13 @@ static int ppc_panic_fadump_handler(struct notifier_block *this,
*/
hard_irq_disable();
+ /*
+ * Invoke kmsg_dump (e.g., pstore) before crash_fadump() as fadump
+ * runs before panic()'s kmsg_dump_desc() call.
+ */
+ if (should_fadump_crash())
+ kmsg_dump_desc(KMSG_DUMP_PANIC, (char *)ptr);
+
/*
* If firmware-assisted dump has been registered then trigger
* its callback and let the firmware handles everything else.
Changes look good to me.
Feel free to add:
Reviewed-by: Sourabh Jain <[email protected]>
- Sourabh Jain
