The patch titled Subject: arm64: kernel: initialize missing kexec_buf->random field has been added to the -mm mm-hotfixes-unstable branch. Its filename is arm64-kernel-initialize-missing-kexec_buf-random-field.patch
This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...
This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------ From: Yeoreum Yun yeoreum.yun@arm.com Subject: arm64: kernel: initialize missing kexec_buf->random field Date: Thu, 27 Nov 2025 18:26:44 +0000
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.
Link: https://lkml.kernel.org/r/20251127182644.1577592-1-yeoreum.yun@arm.com Fixes: bf454ec31add ("kexec_file: allow to place kexec_buf randomly") Signed-off-by: Yeoreum Yun yeoreum.yun@arm.com Cc: Baoquan He bhe@redhat.com Cc: Breno Leitao leitao@debian.org Cc: Catalin Marinas catalin.marinas@arm.com Cc: Coiby Xu coxu@redhat.com Cc: levi.yun yeoreum.yun@arm.com Cc: Will Deacon will@kernel.org Cc: Jan Pazdziora jpazdziora@redhat.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
arch/arm64/kernel/kexec_image.c | 3 +++ arch/arm64/kernel/machine_kexec_file.c | 6 +++++- 2 files changed, 8 insertions(+), 1 deletion(-)
--- a/arch/arm64/kernel/kexec_image.c~arm64-kernel-initialize-missing-kexec_buf-random-field +++ a/arch/arm64/kernel/kexec_image.c @@ -76,6 +76,9 @@ static void *image_load(struct kimage *i kbuf.buf_min = 0; kbuf.buf_max = ULONG_MAX; kbuf.top_down = false; +#ifdef CONFIG_CRASH_DUMP + kbuf.random = false; +#endif
kbuf.buffer = kernel; kbuf.bufsz = kernel_len; --- a/arch/arm64/kernel/machine_kexec_file.c~arm64-kernel-initialize-missing-kexec_buf-random-field +++ a/arch/arm64/kernel/machine_kexec_file.c @@ -94,7 +94,11 @@ int load_other_segments(struct kimage *i char *initrd, unsigned long initrd_len, char *cmdline) { - struct kexec_buf kbuf = {}; + struct kexec_buf kbuf = { +#ifdef CONFIG_CRASH_DUMP + .random = false, +#endif + }; void *dtb = NULL; unsigned long initrd_load_addr = 0, dtb_len, orig_segments = image->nr_segments; _
Patches currently in -mm which might be from yeoreum.yun@arm.com are
arm64-kernel-initialize-missing-kexec_buf-random-field.patch