Re: [PATCH 0/3] kexec: Fix invalid field access

[Baoquan He <bhe@redhat.com>]

On 08/27/25 at 03:42am, Breno Leitao wrote:
> The kexec_buf structure was previously declared without initialization.
> commit bf454ec31add ("kexec_file: allow to place kexec_buf randomly")
> added a field that is always read but not consistently populated by all
> architectures. This un-initialized field will contain garbage.
> 
> This is also triggering a UBSAN warning when the uninitialized data was
> accessed:
> 
> 	------------[ cut here ]------------
> 	UBSAN: invalid-load in ./include/linux/kexec.h:210:10
> 	load of value 252 is not a valid value for type '_Bool'
> 
> Zero-initializing kexec_buf at declaration ensures all fields are
> cleanly set, preventing future instances of uninitialized memory being
> used.
> 
> An initial fix was already landed for arm64[0], and this patchset fixes
> the problem on the remaining arm64 code and on riscv, as raised by Mark.
> 
> Discussions about this problem could be found at[1][2].
> 
> Link: https://lore.kernel.org/all/20250826180742.f2471131255ec1c43683ea07@linux-foundation.org/ [0]
> Link: https://lore.kernel.org/all/oninomspajhxp4omtdapxnckxydbk2nzmrix7rggmpukpnzadw@c67o7njgdgm3/ [1]
> Link: https://lore.kernel.org/all/20250826-akpm-v1-1-3c831f0e3799@debian.org/ [2]
> 
> Signed-off-by: Breno Leitao <leitao@debian.org>
> ---
> Breno Leitao (3):
>       arm64: kexec: Initialize kexec_buf struct in load_other_segments()
>       riscv: kexec: Initialize kexec_buf struct
>       s390: kexec: Initialize kexec_buf struct

Thanks for the fix, all looks good to me.

Acked-by: Baoquan He <bhe@redhat.com>