From: sashiko-bot@kernel.org
To: "George Guo" <dongtai.guo@linux.dev>
Cc: bpf@vger.kernel.org
Subject: Re: [PATCH bpf-next v2 01/11] LoongArch: BPF: Fix tail call count pointer offset for arena programs
Date: Thu, 02 Jul 2026 02:35:32 +0000 [thread overview]
Message-ID: <20260702023533.2E1201F000E9@smtp.kernel.org> (raw)
In-Reply-To: <20260702022322.51033-2-dongtai.guo@linux.dev>
Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] The newly added multi-line comments violate the BPF subsystem's preferred comment style.
--
commit a7174bab96fc4c6edb488f83bc8733f74eac78c7
Author: George Guo <guodongtai@kylinos.cn>
LoongArch: BPF: Fix tail call count pointer offset for arena programs
This commit replaces the BPF_TAIL_CALL_CNT_PTR_STACK_OFF macro with a helper
function, tail_call_cnt_ptr_stack_off(). This function properly accounts for
the REG_ARENA slot in arena programs, resolving an issue where the JIT loaded
the counter value instead of the tail call count pointer.
Link: https://lore.kernel.org/all/20260629085511.359546-1-dongtai.guo@linux.dev
> diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c
> index ad7e28375aa95..5e34e9e3f5086 100644
> --- a/arch/loongarch/net/bpf_jit.c
> +++ b/arch/loongarch/net/bpf_jit.c
> @@ -25,7 +25,23 @@
>
> #define REG_TCC LOONGARCH_GPR_A6
> #define REG_ARENA LOONGARCH_GPR_S6 /* For storing arena_vm_start */
> -#define BPF_TAIL_CALL_CNT_PTR_STACK_OFF(stack) (round_up(stack, 16) - 80)
> +
> +static int tail_call_cnt_ptr_stack_off(struct jit_ctx *ctx)
> +{
> + /* Ten words are pushed below the BPF stack: ra, fp, s0-s5, and the
> + * tail call count plus its pointer, which occupy the two deepest
> + * slots of the callee-saved area.
> + */
[Severity: Low]
This isn't a bug, but does this multi-line comment format adhere to the BPF
subsystem's preferred style? Multi-line comments in BPF-related paths usually
require the opening /* to be on its own line.
> + int offset = sizeof(long) * 10;
> +
> + /* An arena program reserves one extra word above them (REG_ARENA),
> + * which pushes the tail call count pointer down by one slot.
> + */
[Severity: Low]
This isn't a bug, but this comment also doesn't follow the preferred BPF
subsystem multi-line comment style of placing the opening /* on its own line.
> + if (ctx->arena_vm_start)
> + offset += sizeof(long);
> +
> + return round_up(ctx->stack_size, 16) - offset;
> +}
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260702022322.51033-1-dongtai.guo@linux.dev?part=1
next prev parent reply other threads:[~2026-07-02 2:35 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-02 2:23 [PATCH bpf-next v2 00/11] LoongArch: BPF: arena features, exceptions, private stack and may_goto George Guo
2026-07-02 2:23 ` [PATCH bpf-next v2 01/11] LoongArch: BPF: Fix tail call count pointer offset for arena programs George Guo
2026-07-02 2:35 ` sashiko-bot [this message]
2026-07-02 2:23 ` [PATCH bpf-next v2 02/11] LoongArch: BPF: Support internal-only MOV to resolve per-CPU addrs George Guo
2026-07-02 2:23 ` [PATCH bpf-next v2 03/11] LoongArch: BPF: Add timed may_goto support George Guo
2026-07-02 2:23 ` [PATCH bpf-next v2 04/11] LoongArch: BPF: Add private stack support George Guo
2026-07-02 2:23 ` [PATCH bpf-next v2 05/11] LoongArch: BPF: Add exceptions (bpf_throw) support George Guo
2026-07-02 2:39 ` sashiko-bot
2026-07-02 2:23 ` [PATCH bpf-next v2 06/11] LoongArch: BPF: Support sign-extending loads from arena George Guo
2026-07-02 2:23 ` [PATCH bpf-next v2 07/11] LoongArch: BPF: Support atomics on arena pointers George Guo
2026-07-02 2:48 ` sashiko-bot
2026-07-02 2:23 ` [PATCH bpf-next v2 08/11] selftests/bpf: Enable struct_ops private stack test for LoongArch George Guo
2026-07-02 2:23 ` [PATCH bpf-next v2 09/11] selftests/bpf: Enable arena LDSX tests on LoongArch George Guo
2026-07-02 2:23 ` [PATCH bpf-next v2 10/11] selftests/bpf: Enable arena atomics " George Guo
2026-07-02 2:49 ` sashiko-bot
2026-07-02 2:23 ` [PATCH bpf-next v2 11/11] selftests/bpf: Add LoongArch deny list George Guo
2026-07-03 10:11 ` [PATCH bpf-next v2 00/11] LoongArch: BPF: arena features, exceptions, private stack and may_goto Huacai Chen
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