Re: [PATCH] arm64: kernel: initialize missing kexec_buf->random field

[Baoquan He <bhe@redhat.com>]

On 11/27/25 at 11:37am, Andrew Morton wrote:
> On Thu, 27 Nov 2025 18:26:44 +0000 Yeoreum Yun <yeoreum.yun@arm.com> wrote:
> 
> > 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")
> 
> Thanks, I'll add a cc:stable to this.

This has been fixed in below series from Breno Leitao.

[PATCH 0/3] kexec: Fix invalid field access
https://lore.kernel.org/all/20250827-kbuf_all-v1-0-1df9882bb01a@debian.org/T/#u

And Paul Walmsley said he has merged the series to riscv/linux.git.
While I can only see the patch for risc-v. The other two are missing.

95c54cd9c769 riscv: kexec: Initialize kexec_buf struct