From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,T_DKIMWL_WL_HIGH,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6FADEC28CC5 for ; Sat, 8 Jun 2019 11:44:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 47E84214AF for ; Sat, 8 Jun 2019 11:44:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559994267; bh=0RdBvR7NS4NcK/RtuYqQMlazgPB8lT4PeYgDNtn3YGc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=C0WKMZBXoWsHtYpE7QiEjsn/8bovk7SDfbLM381+yoy8oTI+zqqSdJFbpW7zWUmlH +VAhQFwgymWCiliMel9+tJnFj3AXLxVXoWKJmkfTMb0d0NzyPqeZw3qXVZM0zIj+jA 3QUB2XTllGVd0jwxmCVGDmZEBYMwxihmJayHVD+g= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728930AbfFHLo0 (ORCPT ); Sat, 8 Jun 2019 07:44:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:33426 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728132AbfFHLoY (ORCPT ); Sat, 8 Jun 2019 07:44:24 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 72D9F214AF; Sat, 8 Jun 2019 11:44:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559994263; bh=0RdBvR7NS4NcK/RtuYqQMlazgPB8lT4PeYgDNtn3YGc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mOetf323Rk/y6ZPCtcFUppCgUlt4/5cvxJVs94vMJkdVXdFkDzNkVSh6YlOw6fvJM 6sTD+uByeXaudajizlC+ZUjbpzO18Bfjy8hkDC+ZTjfpRrytiywD8DOcfYdpIIQr+D S8BuXKl9tao/NRj8BDpadrpE/zOjQeuIX6ZjrEew= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Thomas Richter , Hendrik Brueckner , Heiko Carstens , Arnaldo Carvalho de Melo , Sasha Levin Subject: [PATCH AUTOSEL 4.19 32/49] perf record: Fix s390 missing module symbol and warning for non-root users Date: Sat, 8 Jun 2019 07:42:13 -0400 Message-Id: <20190608114232.8731-32-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190608114232.8731-1-sashal@kernel.org> References: <20190608114232.8731-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Thomas Richter [ Upstream commit 6738028dd57df064b969d8392c943ef3b3ae705d ] Command 'perf record' and 'perf report' on a system without kernel debuginfo packages uses /proc/kallsyms and /proc/modules to find addresses for kernel and module symbols. On x86 this works for root and non-root users. On s390, when invoked as non-root user, many of the following warnings are shown and module symbols are missing: proc/{kallsyms,modules} inconsistency while looking for "[sha1_s390]" module! Command 'perf record' creates a list of module start addresses by parsing the output of /proc/modules and creates a PERF_RECORD_MMAP record for the kernel and each module. The following function call sequence is executed: machine__create_kernel_maps machine__create_module modules__parse machine__create_module --> for each line in /proc/modules arch__fix_module_text_start Function arch__fix_module_text_start() is s390 specific. It opens file /sys/module//sections/.text to extract the module's .text section start address. On s390 the module loader prepends a header before the first section, whereas on x86 the module's text section address is identical the the module's load address. However module section files are root readable only. For non-root the read operation fails and machine__create_module() returns an error. Command perf record does not generate any PERF_RECORD_MMAP record for loaded modules. Later command perf report complains about missing module maps. To fix this function arch__fix_module_text_start() always returns success. For root users there is no change, for non-root users the module's load address is used as module's text start address (the prepended header then counts as part of the text section). This enable non-root users to use module symbols and avoid the warning when perf report is executed. Output before: [tmricht@m83lp54 perf]$ ./perf report -D | fgrep MMAP 0 0x168 [0x50]: PERF_RECORD_MMAP ... x [kernel.kallsyms]_text Output after: [tmricht@m83lp54 perf]$ ./perf report -D | fgrep MMAP 0 0x168 [0x50]: PERF_RECORD_MMAP ... x [kernel.kallsyms]_text 0 0x1b8 [0x98]: PERF_RECORD_MMAP ... x /lib/modules/.../autofs4.ko.xz 0 0x250 [0xa8]: PERF_RECORD_MMAP ... x /lib/modules/.../sha_common.ko.xz 0 0x2f8 [0x98]: PERF_RECORD_MMAP ... x /lib/modules/.../des_generic.ko.xz Signed-off-by: Thomas Richter Reviewed-by: Hendrik Brueckner Cc: Heiko Carstens Link: http://lkml.kernel.org/r/20190522144601.50763-4-tmricht@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin --- tools/perf/arch/s390/util/machine.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/tools/perf/arch/s390/util/machine.c b/tools/perf/arch/s390/util/machine.c index 0b2054007314..a19690a17291 100644 --- a/tools/perf/arch/s390/util/machine.c +++ b/tools/perf/arch/s390/util/machine.c @@ -5,16 +5,19 @@ #include "util.h" #include "machine.h" #include "api/fs/fs.h" +#include "debug.h" int arch__fix_module_text_start(u64 *start, const char *name) { + u64 m_start = *start; char path[PATH_MAX]; snprintf(path, PATH_MAX, "module/%.*s/sections/.text", (int)strlen(name) - 2, name + 1); - - if (sysfs__read_ull(path, (unsigned long long *)start) < 0) - return -1; + if (sysfs__read_ull(path, (unsigned long long *)start) < 0) { + pr_debug2("Using module %s start:%#lx\n", path, m_start); + *start = m_start; + } return 0; } -- 2.20.1