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

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/ (local) [0]
Link: https://lore.kernel.org/all/oninomspajhxp4omtdapxnckxydbk2nzmrix7rggmpukpnzadw@c67o7njgdgm3/ (local) [1]
Link: https://lore.kernel.org/all/20250826-akpm-v1-1-3c831f0e3799@debian.org/ (local) [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 <redacted>