| Message ID | 20210809093437.876558-7-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 | 2 maintainers not CCed: tsbogend@alpha.franken.de linux-mips@vger.kernel.org |
| 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: 4 this patch: 4 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 16 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 0 this patch: 0 |
| netdev/header_inline | success | Link |
diff --git a/arch/mips/net/ebpf_jit.c b/arch/mips/net/ebpf_jit.c index 3a73e9375712..a93121d71c80 100644 --- a/arch/mips/net/ebpf_jit.c +++ b/arch/mips/net/ebpf_jit.c @@ -617,14 +617,14 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx, int this_idx) b_off = b_imm(this_idx + 1, ctx); emit_instr(ctx, bne, MIPS_R_AT, MIPS_R_ZERO, b_off); /* - * if (TCC-- < 0) + * if (TCC-- <= 0) * goto out; */ /* Delay slot */ tcc_reg = (ctx->flags & EBPF_TCC_IN_V1) ? MIPS_R_V1 : MIPS_R_S4; emit_instr(ctx, daddiu, MIPS_R_T5, tcc_reg, -1); b_off = b_imm(this_idx + 1, ctx); - emit_instr(ctx, bltz, tcc_reg, b_off); + emit_instr(ctx, blez, tcc_reg, b_off); /* * prog = array->ptrs[index]; * if (prog == NULL)
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-mips64. Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com> --- arch/mips/net/ebpf_jit.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)