From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELvhk3a4u8GKLefvOk3vol5xJPTdgPAY9Kd9971KGUid1mmNwjjMyE1pyS41GHbNSPoqucwr ARC-Seal: i=1; a=rsa-sha256; t=1521486200; cv=none; d=google.com; s=arc-20160816; b=x6RZ9+A/PfKXgWfb0eJogeOXuYstTZbG5NQBeGPXKktUips2x5WignB1VqA0nNbSsI 85tVxmp8hg7H3M6vkVezOaXxmQQlWIKxbPC06xze8wKFB8t2whoovc/+STdwhWnPBkh9 HeLjo29heVszTxVD2HX21ldjLc/VQAVf1BkAigdCgLSuiyoUog3x0d1yO9vEvLpjeUcO EomhL5XD7nja4NFTf+L7iRcM01JeMNyCA+d48ZHLhxNMtkeVahjfvbv9uDFO1zCeVyhv i5vIgspP4ynBpXd8ykSdKE7u/VkfoOOyvWTHS2siF0qcVgupCNtfB8pmJnCDbcgBO2O6 yjAg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:references:in-reply-to:message-id:date :subject:cc:to:from:dmarc-filter:arc-authentication-results; bh=Uy7RalgXfEQ7otTEqf2fKfsuVbqGZsUNmxogIHNRa+I=; b=0SP3IHYVO5A9VK74qveLnVR6fmruXJZ9Q/vhoZLpYbChNHgtRgyajdHTEIuMJe6ODX nJ+Q0WHAB7hOgSlegq1gzMhc6Yu3nOYBXVeKnm5aKjnypk8/GFhS9zgXWjpOscWkI5xd vP/knClqj/698rW36B/qjbnT7i2hWInXdj9eG8nmF3M7CIk3ymErzffi0AQGswh7xoBu 29QVxpQtU9A6o0cCAt672pZmmJNu3Rmw1DaVMSJTdb+wtVhqncu4BRd2r/3c/Ferzc2Q +CMW1YWSj9oNEeAuyJvyYAeq3B4hE9u9JanIoezP6xxRlGiLiMAA+iq71LINy3bq7DGs a2Kg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kselftest-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kselftest-owner@vger.kernel.org Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kselftest-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kselftest-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S968451AbeCSTDT (ORCPT ); Mon, 19 Mar 2018 15:03:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:41798 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S970805AbeCSTCX (ORCPT ); Mon, 19 Mar 2018 15:02:23 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9FF63217D5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=acme@kernel.org From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Masami Hiramatsu , Namhyung Kim , Ravi Bangoria , Shuah Khan , Steven Rostedt , Tom Zanussi , linux-kselftest@vger.kernel.org, linux-trace-users@vger.kernel.org, Arnaldo Carvalho de Melo Subject: [PATCH 12/14] perf probe: Use right type to access array elements Date: Mon, 19 Mar 2018 16:01:34 -0300 Message-Id: <20180319190136.7441-13-acme@kernel.org> X-Mailer: git-send-email 2.14.3 In-Reply-To: <20180319190136.7441-1-acme@kernel.org> References: <20180319190136.7441-1-acme@kernel.org> Sender: linux-kselftest-owner@vger.kernel.org X-Mailing-List: linux-kselftest@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1595393913613486395?= X-GMAIL-MSGID: =?utf-8?q?1595393913613486395?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: From: Masami Hiramatsu Current 'perf probe' converts the type of array-elements incorrectly. It always converts the types as a pointer of array. This passes the "array" type DIE to the type converter so that it can get correct "element of array" type DIE from it. E.g. ==== $ cat hello.c #include void foo(int a[]) { printf("%d\n", a[1]); } void main() { int a[3] = {4, 5, 6}; printf("%d\n", a[0]); foo(a); } $ gcc -g hello.c -o hello $ perf probe -x ./hello -D "foo a[1]" ==== Without this fix, above outputs ==== p:probe_hello/foo /tmp/hello:0x4d3 a=+4(-8(%bp)):u64 ==== The "u64" means "int *", but a[1] is "int". With this, ==== p:probe_hello/foo /tmp/hello:0x4d3 a=+4(-8(%bp)):s32 ==== So, "int" correctly converted to "s32" Signed-off-by: Masami Hiramatsu Tested-by: Arnaldo Carvalho de Melo Cc: Namhyung Kim Cc: Ravi Bangoria Cc: Shuah Khan Cc: Steven Rostedt Cc: Tom Zanussi Cc: linux-kselftest@vger.kernel.org Cc: linux-trace-users@vger.kernel.org Fixes: b2a3c12b7442 ("perf probe: Support tracing an entry of array") Link: http://lkml.kernel.org/r/152129114502.31874.2474068470011496356.stgit@devbox Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/probe-finder.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c index a5731de0e5eb..c37fbef1711d 100644 --- a/tools/perf/util/probe-finder.c +++ b/tools/perf/util/probe-finder.c @@ -423,20 +423,20 @@ static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname, pr_warning("Failed to get the type of %s.\n", varname); return -ENOENT; } - pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type)); + pr_debug2("Var real type: %s (%x)\n", dwarf_diename(&type), + (unsigned)dwarf_dieoffset(&type)); tag = dwarf_tag(&type); if (field->name[0] == '[' && (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) { - if (field->next) - /* Save original type for next field */ - memcpy(die_mem, &type, sizeof(*die_mem)); + /* Save original type for next field or type */ + memcpy(die_mem, &type, sizeof(*die_mem)); /* Get the type of this array */ if (die_get_real_type(&type, &type) == NULL) { pr_warning("Failed to get the type of %s.\n", varname); return -ENOENT; } - pr_debug2("Array real type: (%x)\n", + pr_debug2("Array real type: %s (%x)\n", dwarf_diename(&type), (unsigned)dwarf_dieoffset(&type)); if (tag == DW_TAG_pointer_type) { ref = zalloc(sizeof(struct probe_trace_arg_ref)); @@ -448,9 +448,6 @@ static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname, *ref_ptr = ref; } ref->offset += dwarf_bytesize(&type) * field->index; - if (!field->next) - /* Save vr_die for converting types */ - memcpy(die_mem, vr_die, sizeof(*die_mem)); goto next; } else if (tag == DW_TAG_pointer_type) { /* Check the pointer and dereference */ -- 2.14.3