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Yonghong Song says:
====================
bpf: Reduce verifier stack frame size
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@kernel.org/
Changelogs:
v2 -> v3:
- v2: https://lore.kernel.org/bpf/20250702171134.2370432-1-yonghong.song@linux.dev/
- Rename env->callchain to env->callchain_buf so it is clear that
- env->callchain_buf is used for a temp buf.
v1 -> v2:
- v1: https://lore.kernel.org/bpf/20250702053332.1991516-1-yonghong.song@linux.dev/
- 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.
====================
Link: https://patch.msgid.link/20250703141101.1482025-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Linux kernel
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