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[116.14.181.187]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-1f6d859ea3csm61578855ad.178.2024.06.10.05.42.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 Jun 2024 05:42:35 -0700 (PDT) From: Leon Hwang To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, yonghong.song@linux.dev, hffilwlqm@gmail.com, kernel-patches-bot@fb.com Subject: [PATCH v2 bpf-next 1/2] bpf, verifier: Correct tail_call_reachable for bpf prog Date: Mon, 10 Jun 2024 20:42:23 +0800 Message-ID: <20240610124224.34673-2-hffilwlqm@gmail.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240610124224.34673-1-hffilwlqm@gmail.com> References: <20240610124224.34673-1-hffilwlqm@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net It's confusing to inspect 'prog->aux->tail_call_reachable' with drgn[0], when bpf prog has tail call but 'tail_call_reachable' is false. This patch corrects 'tail_call_reachable' when bpf prog has tail call. Signed-off-by: Leon Hwang --- kernel/bpf/verifier.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 81a3d2ced78d5..d7045676246a7 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2982,8 +2982,10 @@ static int check_subprogs(struct bpf_verifier_env *env) if (code == (BPF_JMP | BPF_CALL) && insn[i].src_reg == 0 && - insn[i].imm == BPF_FUNC_tail_call) + insn[i].imm == BPF_FUNC_tail_call) { subprog[cur_subprog].has_tail_call = true; + subprog[cur_subprog].tail_call_reachable = true; + } if (BPF_CLASS(code) == BPF_LD && (BPF_MODE(code) == BPF_ABS || BPF_MODE(code) == BPF_IND)) subprog[cur_subprog].has_ld_abs = true; From patchwork Mon Jun 10 12:42:24 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Leon Hwang X-Patchwork-Id: 13691965 X-Patchwork-Delegate: bpf@iogearbox.net Received: from mail-pg1-f169.google.com (mail-pg1-f169.google.com [209.85.215.169]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 63CD280633 for ; Mon, 10 Jun 2024 12:42:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.169 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718023361; cv=none; b=DbojX8R7iIstSvYLNwrKRlj41WmZl3KD/9QypQEpblXUdU5ZsWanni0TJVmQSQZh548gPENIwykXbwcjPG02KyM+FcrJw7cTyBnvzub85HNsvg3tKaPMH9I8Eo7RgFuEg0OaihP4W8l4d0Qf53rFhTW8N8RRKwQkhNiyuHQ2Zxw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718023361; c=relaxed/simple; bh=kqUQlpaIaDNnrdFw6Q+b+9xVWbGOp2eIMpScWPMeJFQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mgLruO4LLjrCmtoDiVSA8O7EZLve8H6GdVsvLLd4UDfvWpfQ/iyTo/ZpfwVoJkuNjdHYXWqKju79hyGVVbfDi14KWMup4tBuPewXq+kMGo1M76P1h7kFwNXAi2QOw0zuHj4vGprNMszyRk1F5xp1w3pezYwV2x12iCRbYk6dhkU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=ibEUFlMu; arc=none smtp.client-ip=209.85.215.169 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ibEUFlMu" Received: by mail-pg1-f169.google.com with SMTP id 41be03b00d2f7-681ad081695so3252278a12.3 for ; Mon, 10 Jun 2024 05:42:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1718023359; x=1718628159; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=xZWjnYHQtTCBKPuAw0CdIGNLHtOZ3VLe66fV6kQYPvs=; b=ibEUFlMuMQbMM0F+t8aG45xFin1wTqSOTHvAkRrPU8+0so3pbTR5Cm5XYkObiGEtzs kKKerE3X55tpSS5HbpzPaxVuey+yJxZEN6oGplRDSKyknbHFLdS9JUJ4k29TpvMr8QL5 o83NlLtjWmd10v2orzgH/2q/ZFLZgSTiZG/70fjKzowf0aSUSkpa4dCBEuTp48iDcRRt wqHLaXGc9F7Kiy6+WYmo8krrLQbcXzZbJA0K0hGN7T3x4pXdmZm6iuWMji3hn0DCWK7n Ib0yS2VrXY0xmV3LMe+EZKI/PaeTPTZcYxDsh5itHpp1/orqN4XTn2X0HTrzUj95BhpY 9Ecg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1718023359; x=1718628159; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=xZWjnYHQtTCBKPuAw0CdIGNLHtOZ3VLe66fV6kQYPvs=; b=CknopvfYQYMTIWvfXgp56lrvmDw0h4GVbigb9JpcPYspZicosAiZ7wRvngcaih/g9f d0zBMbD7zl1SeSeap4Ora+Qew48c8cGKx167vGsiU3Ty4/wR9jkmNap83l8xQPJmq8OR 6wkL17lfw35iBpcZEomYq6sYiU9BbbCg8rOwAqHF998JW/g0c/ICQUTIRGips7ktt0Go 4rG+2zRuynMAYlBZ2Y+GYbPogOriIxKzh2ku7qiaMxabHegS8wfKuYlTkxpJpFztxeQM 3qD++JY3owINKC72IY9f/Wh1RYkBpOn+7PBXTVEpQB3JHiBH2wfFV3JzD5XiuZVYL1mL T59g== X-Gm-Message-State: AOJu0Yx0DQ9SG7YuQDBqK7R5QTapGE/WkCu7fSmo8UAp2tXdZoHlx6dK lUq3Bebem5Z8kKaZt/QpTeLoswWnDkHwbiv32SD3J6nvr8aQYRJ20QvcQw== X-Google-Smtp-Source: AGHT+IH6DDHaL2r2Jmevtw2fhiAafGhTHcsHfvyH3bjnEUddcYjoXs63WsY2tIW+BCc4giGzPIJqvQ== X-Received: by 2002:a17:902:e752:b0:1f7:234b:4f3d with SMTP id d9443c01a7336-1f7234b8fadmr4568265ad.39.1718023358498; Mon, 10 Jun 2024 05:42:38 -0700 (PDT) Received: from localhost.localdomain (bb116-14-181-187.singnet.com.sg. [116.14.181.187]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-1f6d859ea3csm61578855ad.178.2024.06.10.05.42.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 Jun 2024 05:42:38 -0700 (PDT) From: Leon Hwang To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, yonghong.song@linux.dev, hffilwlqm@gmail.com, kernel-patches-bot@fb.com Subject: [PATCH v2 bpf-next 2/2] bpf, x64: Remove tail call detection Date: Mon, 10 Jun 2024 20:42:24 +0800 Message-ID: <20240610124224.34673-3-hffilwlqm@gmail.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240610124224.34673-1-hffilwlqm@gmail.com> References: <20240610124224.34673-1-hffilwlqm@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net As 'prog->aux->tail_call_reachable' is correct for tail call present, it's unnecessary to detect tail call in x86 jit. Therefore, let's remove it. Signed-off-by: Leon Hwang --- arch/x86/net/bpf_jit_comp.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 5159c7a229229..7c130001fbfe7 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -1234,13 +1234,11 @@ bool ex_handler_bpf(const struct exception_table_entry *x, struct pt_regs *regs) } static void detect_reg_usage(struct bpf_insn *insn, int insn_cnt, - bool *regs_used, bool *tail_call_seen) + bool *regs_used) { int i; for (i = 1; i <= insn_cnt; i++, insn++) { - if (insn->code == (BPF_JMP | BPF_TAIL_CALL)) - *tail_call_seen = true; if (insn->dst_reg == BPF_REG_6 || insn->src_reg == BPF_REG_6) regs_used[0] = true; if (insn->dst_reg == BPF_REG_7 || insn->src_reg == BPF_REG_7) @@ -1324,7 +1322,6 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, u8 *rw_image struct bpf_insn *insn = bpf_prog->insnsi; bool callee_regs_used[4] = {}; int insn_cnt = bpf_prog->len; - bool tail_call_seen = false; bool seen_exit = false; u8 temp[BPF_MAX_INSN_SIZE + BPF_INSN_SAFETY]; u64 arena_vm_start, user_vm_start; @@ -1336,11 +1333,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, u8 *rw_image arena_vm_start = bpf_arena_get_kern_vm_start(bpf_prog->aux->arena); user_vm_start = bpf_arena_get_user_vm_start(bpf_prog->aux->arena); - detect_reg_usage(insn, insn_cnt, callee_regs_used, - &tail_call_seen); - - /* tail call's presence in current prog implies it is reachable */ - tail_call_reachable |= tail_call_seen; + detect_reg_usage(insn, insn_cnt, callee_regs_used); emit_prologue(&prog, bpf_prog->aux->stack_depth, bpf_prog_was_classic(bpf_prog), tail_call_reachable,