[PATCH] ACPI/APEI: Clear GHES block_status before panic()

From: David Arcari
Date: Wed Dec 19 2018 - 11:52:25 EST

From: Lenny Szubowicz <lszubowi@xxxxxxxxxx>

In __ghes_panic() clear the block status in the APEI generic
error status block for that generic hardware error source before
calling panic() to prevent a second panic() in the crash kernel
for exactly the same fatal error.

Otherwise ghes_probe(), running in the crash kernel, would see
an unhandled error in the APEI generic error status block and
panic again, thereby precluding any crash dump.

Signed-off-by: Lenny Szubowicz <lszubowi@xxxxxxxxxx>
Signed-off-by: David Arcari <darcari@xxxxxxxxxx>
Cc: Rafael J. Wysocki <rjw@xxxxxxxxxxxxx>
Cc: Len Brown <lenb@xxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: Alexandru Gagniuc <mr.nuke.me@xxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
drivers/acpi/apei/ghes.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 02c6fd9..f008ba7 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -691,6 +691,8 @@ static void __ghes_panic(struct ghes *ghes)
__ghes_print_estatus(KERN_EMERG, ghes->generic, ghes->estatus);

+ ghes_clear_estatus(ghes);
/* reboot to log the error! */
if (!panic_timeout)
panic_timeout = ghes_panic_timeout;