[PATCH v3 0/2] kexec: fix probe error codes and error propagation

While debugging a misleading error on s390x where kexec -s reported
"syscall kexec_file_load not available" instead of the actual EINVAL
from a kernel command line that exceeded the architecture limit, we
found that some kexec image probe functions return -EINVAL instead of
-ENOEXEC for format mismatches, and kexec_image_probe_default() has a
bug where it returns whatever the last loader returned rather than
always returning -ENOEXEC when no loader matches.

Patch 1 fixes all probe functions to return -ENOEXEC when they do not
recognize the image format.

Patch 2 fixes kexec_image_probe_default() to distinguish format
mismatches (-ENOEXEC) from real errors (e.g. -ENOMEM), propagating
real errors immediately and only continuing to the next loader on
-ENOEXEC.

kexec-tools patch:
https://lore.kernel.org/all/[email protected]/

Signed-off-by: Mukesh Pilaniya <[email protected]>
---
Changes in v3:
- Patch 2: rename ret to err and change ret == 0 to !err as suggested by Mike.
- Link to v2: https://patch.msgid.link/[email protected]

Changes in v2:
- Added patch 2 to fix error propagation in kexec_image_probe_default(),
  as suggested by Pratyush Yadav.
- Link to v1: https://patch.msgid.link/[email protected]

To: Catalin Marinas <[email protected]>
To: Will Deacon <[email protected]>
To: Mark Rutland <[email protected]>
To: Huacai Chen <[email protected]>
To: WANG Xuerui <[email protected]>
To: Paul Walmsley <[email protected]>
To: Palmer Dabbelt <[email protected]>
To: Albert Ou <[email protected]>
To: Alexandre Ghiti <[email protected]>
To: Andrew Morton <[email protected]>
To: Baoquan He <[email protected]>
To: Mike Rapoport <[email protected]>
To: Pasha Tatashin <[email protected]>
To: Pratyush Yadav <[email protected]>
To: Philipp Rudo <[email protected]>
To: Tao Liu <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]

---
Mukesh Pilaniya (2):
      kexec: return -ENOEXEC from image probe functions on mismatch
      kexec: fix error propagation in kexec_image_probe_default()

 arch/arm64/kernel/kexec_image.c   |  4 ++--
 arch/loongarch/kernel/kexec_efi.c |  4 ++--
 arch/riscv/kernel/kexec_image.c   |  4 ++--
 kernel/kexec_elf.c                |  4 ++--
 kernel/kexec_file.c               | 12 +++++++-----
 5 files changed, 15 insertions(+), 13 deletions(-)
---
base-commit: dd8c49a14f169d58e7a07a2c96fb588f3456efa0
change-id: 20260813-mpilaniy-ffb0cc92c313

Best regards,
--  
Mukesh Pilaniya <[email protected]>