From patchwork Thu Oct 12 03:50:56 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Namhyung Kim X-Patchwork-Id: 13418240 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 97E051368; Thu, 12 Oct 2023 03:52:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="jeNudOb1" Received: from mail-pl1-x62b.google.com (mail-pl1-x62b.google.com [IPv6:2607:f8b0:4864:20::62b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0881B10FE; Wed, 11 Oct 2023 20:51:59 -0700 (PDT) Received: by mail-pl1-x62b.google.com with SMTP id d9443c01a7336-1c9daca2b85so3889955ad.1; Wed, 11 Oct 2023 20:51:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1697082718; x=1697687518; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:sender:from:to:cc:subject:date :message-id:reply-to; bh=l0uukPGLNEM1tQxhVgCDG+pFph2Ypn/ZDoH5IEqzJ3I=; b=jeNudOb1UFmXpW89hxAkI3WSiEB6zlvZNbAm5Que5kBkvID8hDLLLKCOiQLA/hBXfS NCbWDJrizyD2dHCeQ9TaQlO78OWvFi7tvOvpd9kBdLPJ24N0d3wtq0nCl3NwvXG5oS+7 hSmqaTQ6r8mZw67GNIlKGMbSVcB+iJUIGXiAVayU9q6eDu22XDNxExiJNVwrlUpfD/Id P4XYlZS3fSwTbXx7CPBz7Q0rO13TRIHfVDBngzD4pm4/xJ7YF01yEkjIioiJdI/B1pzc IVh5kQPiJgN2ViKeI6zPO7oxdYABRC6xL2cuDxi+WwO/0bGalc3G8pnoQa5PmrHs/YZY ROeA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697082718; x=1697687518; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:sender:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=l0uukPGLNEM1tQxhVgCDG+pFph2Ypn/ZDoH5IEqzJ3I=; b=wA71cMn91nK+ya4aySVgXJIYw3kwqWv/EGQ5rko8RspoDU9qHsG+zBPHCHG50tVkuI r9ggxOFXyCsLE3/FUsHPPqjFqBSWE0mes6x0Ev76gVEVCCm0l2PvkVqOL0Bp2wNc7iDR rlM4kutFSB6PjI3nqZN3rGfQwSXN3zykiGEYJKKkw4OIPGrv7vVZAGuiuoIfcg5B9c4Q NOedrqi042YAqGQFicjFMhRRAGigD75xS1pu1cLzaSsYHHcO5weu0+giDz9uiPndbnDc nTEEUMGCIPQdBzRp/gunfgplHl6e1VBDVYjFFOXpiZTjoucd+KNG9kiuvy601CR2zIOl uPfA== X-Gm-Message-State: AOJu0YylSRkGZ+VNS1rrKKcgQDvlot2EOUqJWwLWyPwxG9vzP9ER2OMT 8TDnJy36r2FOlL2bDveRAoM= X-Google-Smtp-Source: AGHT+IEclYaWjsPPKcKoo/WLvGVTPPpcj9luv3OfJd0T5zaVimdTR2Sng9+6xF99eXfZeJP14Uworg== X-Received: by 2002:a17:902:e852:b0:1c5:59dc:6e93 with SMTP id t18-20020a170902e85200b001c559dc6e93mr34503545plg.3.1697082718091; Wed, 11 Oct 2023 20:51:58 -0700 (PDT) Received: from bangji.hsd1.ca.comcast.net ([2601:647:6780:42e0:b1b9:d490:2f5e:be06]) by smtp.gmail.com with ESMTPSA id w8-20020a170902d70800b001bc18e579aesm711374ply.101.2023.10.11.20.51.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 11 Oct 2023 20:51:57 -0700 (PDT) Sender: Namhyung Kim From: Namhyung Kim To: Arnaldo Carvalho de Melo , Jiri Olsa , Peter Zijlstra Cc: Ian Rogers , Adrian Hunter , Ingo Molnar , LKML , linux-perf-users@vger.kernel.org, Linus Torvalds , Stephane Eranian , Masami Hiramatsu , linux-toolchains@vger.kernel.org, linux-trace-devel@vger.kernel.org Subject: [PATCH 33/48] perf dwarf-aux: Check allowed DWARF Ops Date: Wed, 11 Oct 2023 20:50:56 -0700 Message-ID: <20231012035111.676789-34-namhyung@kernel.org> X-Mailer: git-send-email 2.42.0.655.g421f12c284-goog In-Reply-To: <20231012035111.676789-1-namhyung@kernel.org> References: <20231012035111.676789-1-namhyung@kernel.org> Precedence: bulk X-Mailing-List: linux-trace-devel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-1.5 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net The DWARF location expression can be fairly complex and it'd be hard to match it with the condition correctly. So let's be conservative and only allow simple expressions. For now it just checks the first operation in the list. The following operations looks ok: * DW_OP_stack_value * DW_OP_deref_size * DW_OP_deref * DW_OP_piece To refuse complex (and unsupported) location expressions, add check_allowed_ops() to compare the rest of the list. It seems earlier result contained those unsupported expressions. For example, I found some local struct variable is placed like below. <2><43d1517>: Abbrev Number: 62 (DW_TAG_variable) <43d1518> DW_AT_location : 15 byte block: 91 50 93 8 91 78 93 4 93 84 8 91 68 93 4 (DW_OP_fbreg: -48; DW_OP_piece: 8; DW_OP_fbreg: -8; DW_OP_piece: 4; DW_OP_piece: 1028; DW_OP_fbreg: -24; DW_OP_piece: 4) Another example is something like this. 0057c8be ffffffffffffffff ffffffff812109f0 (base address) 0057c8ce ffffffff812112b5 ffffffff812112c8 (DW_OP_breg3 (rbx): 0; DW_OP_constu: 18446744073709551612; DW_OP_and; DW_OP_stack_value) It should refuse them. After the change, the stat shows: Annotate data type stats: total 294, ok 158 (53.7%), bad 136 (46.3%) ----------------------------------------------------------- 30 : no_sym 32 : no_mem_ops 53 : no_var 14 : no_typeinfo 7 : bad_offset Signed-off-by: Namhyung Kim Acked-by: Masami Hiramatsu (Google) --- tools/perf/util/dwarf-aux.c | 44 +++++++++++++++++++++++++++++++++---- 1 file changed, 40 insertions(+), 4 deletions(-) diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c index 7f3822d08ab7..093d7e82b333 100644 --- a/tools/perf/util/dwarf-aux.c +++ b/tools/perf/util/dwarf-aux.c @@ -1305,6 +1305,34 @@ static bool match_var_offset(Dwarf_Die *die_mem, struct find_var_data *data, return true; } +static bool check_allowed_ops(Dwarf_Op *ops, size_t nops) +{ + /* The first op is checked separately */ + ops++; + nops--; + + /* + * It needs to make sure if the location expression matches to the given + * register and offset exactly. Thus it rejects any complex expressions + * and only allows a few of selected operators that doesn't change the + * location. + */ + while (nops) { + switch (ops->atom) { + case DW_OP_stack_value: + case DW_OP_deref_size: + case DW_OP_deref: + case DW_OP_piece: + break; + default: + return false; + } + ops++; + nops--; + } + return true; +} + /* Only checks direct child DIEs in the given scope. */ static int __die_find_var_reg_cb(Dwarf_Die *die_mem, void *arg) { @@ -1332,25 +1360,31 @@ static int __die_find_var_reg_cb(Dwarf_Die *die_mem, void *arg) /* Local variables accessed using frame base register */ if (data->is_fbreg && ops->atom == DW_OP_fbreg && data->offset >= (int)ops->number && + check_allowed_ops(ops, nops) && match_var_offset(die_mem, data, data->offset, ops->number)) return DIE_FIND_CB_END; /* Only match with a simple case */ if (data->reg < DWARF_OP_DIRECT_REGS) { - if (ops->atom == (DW_OP_reg0 + data->reg) && nops == 1) + /* pointer variables saved in a register 0 to 31 */ + if (ops->atom == (DW_OP_reg0 + data->reg) && + check_allowed_ops(ops, nops)) return DIE_FIND_CB_END; /* Local variables accessed by a register + offset */ if (ops->atom == (DW_OP_breg0 + data->reg) && + check_allowed_ops(ops, nops) && match_var_offset(die_mem, data, data->offset, ops->number)) return DIE_FIND_CB_END; } else { + /* pointer variables saved in a register 32 or above */ if (ops->atom == DW_OP_regx && ops->number == data->reg && - nops == 1) + check_allowed_ops(ops, nops)) return DIE_FIND_CB_END; /* Local variables accessed by a register + offset */ if (ops->atom == DW_OP_bregx && data->reg == ops->number && + check_allowed_ops(ops, nops) && match_var_offset(die_mem, data, data->offset, ops->number2)) return DIE_FIND_CB_END; } @@ -1412,7 +1446,8 @@ static int __die_find_var_addr_cb(Dwarf_Die *die_mem, void *arg) if (data->addr < ops->number) continue; - if (match_var_offset(die_mem, data, data->addr, ops->number)) + if (check_allowed_ops(ops, nops) && + match_var_offset(die_mem, data, data->addr, ops->number)) return DIE_FIND_CB_END; } return DIE_FIND_CB_SIBLING; @@ -1501,7 +1536,8 @@ int die_get_cfa(Dwarf *dwarf, u64 pc, int *preg, int *poffset) return -1; if (!dwarf_cfi_addrframe(cfi, pc, &frame) && - !dwarf_frame_cfa(frame, &ops, &nops) && nops == 1) { + !dwarf_frame_cfa(frame, &ops, &nops) && + check_allowed_ops(ops, nops)) { *preg = reg_from_dwarf_op(ops); *poffset = offset_from_dwarf_op(ops); return 0;