Arnd Bergmann reported an issue ([1]) where clang compiler (less than
llvm18) may trigger an error where the stack frame size exceeds the limit.
I can reproduce the error like below:
kernel/bpf/verifier.c:24491:5: error: stack frame size (2552) exceeds limit (1280) in 'bpf_check'
[-Werror,-Wframe-larger-than]
kernel/bpf/verifier.c:19921:12: error: stack frame size (1368) exceeds limit (1280) in 'do_check'
[-Werror,-Wframe-larger-than]
This patch series fixed the above two errors by reducing stack size.
See each individual patches for details.
[1] https://lore.kernel.org/bpf/20250620113846.3950478-1-arnd@xxxxxxxxxx/
Changelogs:
v1 -> v2:
- v1: https://lore.kernel.org/bpf/20250702053332.1991516-1-yonghong.song@xxxxxxxxx/
- Simplify assignment to struct bpf_insn pointer in do_misc_fixups().
- Restore original implementation in opt_hard_wire_dead_code_branches()
as only one insn on the stack.
- Avoid unnecessary insns for 64bit modulo (mod 0/-1) operations.
Yonghong Song (3):
bpf: Simplify assignment to struct bpf_insn pointer in
do_misc_fixups()
bpf: Reduce stack frame size by using env->insn_buf for bpf insns
bpf: Avoid putting struct bpf_scc_callchain variables on the stack
include/linux/bpf_verifier.h | 1 +
kernel/bpf/verifier.c | 229 +++++++++++++++++------------------
2 files changed, 112 insertions(+), 118 deletions(-)
--
2.47.1
