[PATCH 6.18 495/752] arm64: kernel: initialize missing kexec_buf->random field

Sasha Levin
2026-02-28T17:55:10Z

From: Yeoreum Yun <yeoreum.yun@arm.com>

[ Upstream commit 15dd20dda979ebab72f6df97845828e78d63ab91 ]

Commit bf454ec31add ("kexec_file: allow to place kexec_buf randomly")
introduced the kexec_buf->random field to enable random placement of
kexec_buf.

However, this field was never properly initialized for kexec images
that do not need to be placed randomly, leading to the following UBSAN
warning:

[ +0.364528] ------------[ cut here ]------------
[ +0.000019] UBSAN: invalid-load in ./include/linux/kexec.h:210:12
[ +0.000131] load of value 2 is not a valid value for type 'bool' (aka '_Bool')
[ +0.000003] CPU: 4 UID: 0 PID: 927 Comm: kexec Not tainted 6.18.0-rc7+ #3 PREEMPT(full)
[ +0.000002] Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
[ +0.000000] Call trace:
[ +0.000001] show_stack+0x24/0x40 (C)
[ +0.000006] __dump_stack+0x28/0x48
[ +0.000002] dump_stack_lvl+0x7c/0xb0
[ +0.000002] dump_stack+0x18/0x34
[ +0.000001] ubsan_epilogue+0x10/0x50
[ +0.000002] __ubsan_handle_load_invalid_value+0xc8/0xd0
[ +0.000003] locate_mem_hole_callback+0x28c/0x2a0
[ +0.000003] kexec_locate_mem_hole+0xf4/0x2f0
[ +0.000001] kexec_add_buffer+0xa8/0x178
[ +0.000002] image_load+0xf0/0x258
[ +0.000001] __arm64_sys_kexec_file_load+0x510/0x718
[ +0.000002] invoke_syscall+0x68/0xe8
[ +0.000001] el0_svc_common+0xb0/0xf8
[ +0.000002] do_el0_svc+0x28/0x48
[ +0.000001] el0_svc+0x40/0xe8
[ +0.000002] el0t_64_sync_handler+0x84/0x140
[ +0.000002] el0t_64_sync+0x1bc/0x1c0

To address this, initialise kexec_buf->random field properly.

Fixes: bf454ec31add ("kexec_file: allow to place kexec_buf randomly")
Suggested-by: Breno Leitao <leitao@debian.org>
Cc: stable@vger.kernel.org
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
Reviewed-by: Breno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/all/oninomspajhxp4omtdapxnckxydbk2nzmrix7rggmpukpnzadw@c67o7njgdgm3/ [1]
Link: https://lore.kernel.org/all/20250825180531.94bfb86a26a43127c0a1296f@linux-foundation.org/ [2]
Link: https://lkml.kernel.org/r/20250826-akpm-v1-1-3c831f0e3799@debian.org
Signed-off-by: Breno Leitao <leitao@debian.org>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/arm64/kernel/kexec_image.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/kexec_image.c b/arch/arm64/kernel/kexec_image.c
index 532d72ea42ee8..b70f4df15a1ae 100644
--- a/arch/arm64/kernel/kexec_image.c
+++ b/arch/arm64/kernel/kexec_image.c
@@ -41,7 +41,7 @@ static void *image_load(struct kimage *image,
struct arm64_image_header *h;
u64 flags, value;
bool be_image, be_kernel;
- struct kexec_buf kbuf;
+ struct kexec_buf kbuf = {};
unsigned long text_offset, kernel_segment_number;
struct kexec_segment *kernel_segment;
int ret;
--
2.51.0