| Message ID | 20210809093437.876558-3-johan.almbladh@anyfinetworks.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | BPF |
| Headers | show |
| Series | Fix MAX_TAIL_CALL_CNT handling in eBPF JITs | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Clearly marked for bpf-next |
| netdev/subject_prefix | success | Link |
| netdev/cc_maintainers | warning | 3 maintainers not CCed: linux-arm-kernel@lists.infradead.org will@kernel.org catalin.marinas@arm.com |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 0 this patch: 0 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 13 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 0 this patch: 0 |
| netdev/header_inline | success | Link |
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index 41c23f474ea6..cda53e33bbec 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -286,11 +286,11 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx) emit(A64_CMP(0, r3, tmp), ctx); emit(A64_B_(A64_COND_CS, jmp_offset), ctx); - /* if (tail_call_cnt > MAX_TAIL_CALL_CNT) + /* if (tail_call_cnt >= MAX_TAIL_CALL_CNT) * goto out; * tail_call_cnt++; */ - emit_a64_mov_i64(tmp, MAX_TAIL_CALL_CNT, ctx); + emit_a64_mov_i64(tmp, MAX_TAIL_CALL_CNT - 1, ctx); emit(A64_CMP(1, tcc, tmp), ctx); emit(A64_B_(A64_COND_HI, jmp_offset), ctx); emit(A64_ADD_I(1, tcc, tcc, 1), ctx);
Before, the eBPF JIT allowed up to MAX_TAIL_CALL_CNT + 1 tail calls. Now, precisely MAX_TAIL_CALL_CNT is allowed, which is in line with the behaviour of the interpreter. Verified with the test_bpf test suite on qemu-system-aarch64. Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com> --- arch/arm64/net/bpf_jit_comp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)