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@xxxxxxxxxxxxxxxxxxxx/ [0]
Link: https://lore.kernel.org/all/oninomspajhxp4omtdapxnckxydbk2nzmrix7rggmpukpnzadw@c67o7njgdgm3/ [1]
Link: https://lore.kernel.org/all/20250826-akpm-v1-1-3c831f0e3799@xxxxxxxxxx/ [2]
Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>
---
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
arch/arm64/kernel/machine_kexec_file.c | 2 +-
arch/riscv/kernel/kexec_elf.c | 4 ++--
arch/riscv/kernel/kexec_image.c | 2 +-
arch/riscv/kernel/machine_kexec_file.c | 2 +-
arch/s390/kernel/kexec_elf.c | 2 +-
arch/s390/kernel/kexec_image.c | 2 +-
arch/s390/kernel/machine_kexec_file.c | 6 +++---
7 files changed, 10 insertions(+), 10 deletions(-)
---
base-commit: 3c642997252eef4449cb6b6e02af3dc22515d817
change-id: 20250827-kbuf_all-b9d55c9291eb
Best regards,
--
Breno Leitao <leitao@xxxxxxxxxx>
