Commit e67f0bd0 authored Aug 27, 2025 by Breno Leitao Committed by Andrew Morton Sep 03, 2025

s390: kexec: initialize kexec_buf struct

The kexec_buf structure was previously declared without initialization.
commit bf454ec3 ("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.

Link: https://lkml.kernel.org/r/20250827-kbuf_all-v1-3-1df9882bb01a@debian.org


Fixes: bf454ec3 ("kexec_file: allow to place kexec_buf randomly")
Signed-off-by: Breno Leitao <leitao@debian.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Baoquan He <bhe@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Coiby Xu <coxu@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

parent 8afbd004

arch/s390/kernel/kexec_elf.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -16,7 +16,7 @@
		static int kexec_file_add_kernel_elf(struct kimage *image,
		struct s390_load_data *data)
		{
		struct kexec_buf buf;
		struct kexec_buf buf = {};
		const Elf_Ehdr *ehdr;
		const Elf_Phdr *phdr;
		Elf_Addr entry;

arch/s390/kernel/kexec_image.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -16,7 +16,7 @@
		static int kexec_file_add_kernel_image(struct kimage *image,
		struct s390_load_data *data)
		{
		struct kexec_buf buf;
		struct kexec_buf buf = {};

		buf.image = image;

arch/s390/kernel/machine_kexec_file.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -129,7 +129,7 @@ static int kexec_file_update_purgatory(struct kimage *image,
		static int kexec_file_add_purgatory(struct kimage *image,
		struct s390_load_data *data)
		{
		struct kexec_buf buf;
		struct kexec_buf buf = {};
		int ret;

		buf.image = image;
		@@ -152,7 +152,7 @@ static int kexec_file_add_purgatory(struct kimage *image,
		static int kexec_file_add_initrd(struct kimage *image,
		struct s390_load_data *data)
		{
		struct kexec_buf buf;
		struct kexec_buf buf = {};
		int ret;

		buf.image = image;
		@@ -184,7 +184,7 @@ static int kexec_file_add_ipl_report(struct kimage *image,
		{
		__u32 *lc_ipl_parmblock_ptr;
		unsigned int len, ncerts;
		struct kexec_buf buf;
		struct kexec_buf buf = {};
		unsigned long addr;
		void ptr, end;
		int ret;