linux-kernel - [PATCH] efi: fix panic in kdump kernel

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Date: Fri, 22 Mar 2024 01:08:45 +0000
From: Oleksandr Tymoshenko <ovt@...gle.com>
To: Ard Biesheuvel <ardb@...nel.org>
Cc: ovt@...gle.com, johan+linaro@...nel.org, linux-efi@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: [PATCH] efi: fix panic in kdump kernel

Check if get_next_variable() is actually valid pointer before
calling it. In kdump kernel this method is set to NULL that causes
panic during the kexec-ed kernel boot.

Tested with QEMU and OVMF firmware.

Signed-off-by: Oleksandr Tymoshenko <ovt@...gle.com>
---
 drivers/firmware/efi/efi.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 8859fb0b006d..800b85807a02 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -203,6 +203,8 @@ static bool generic_ops_supported(void)
 
 	name_size = sizeof(name);
 
+	if (efi.get_next_variable == NULL)
+		return false;
 	status = efi.get_next_variable(&name_size, &name, &guid);
 	if (status == EFI_UNSUPPORTED)
 		return false;
-- 
2.44.0.396.g6e790dbe36-goog