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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 8A651C43331 for ; Tue, 12 Nov 2019 12:03:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5F8A32084E for ; Tue, 12 Nov 2019 12:03:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726697AbfKLMDg (ORCPT ); Tue, 12 Nov 2019 07:03:36 -0500 Received: from foss.arm.com ([217.140.110.172]:32788 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725944AbfKLMDg (ORCPT ); Tue, 12 Nov 2019 07:03:36 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9297231B; Tue, 12 Nov 2019 04:03:35 -0800 (PST) Received: from e120877-lin.cambridge.arm.com (e120877-lin.cambridge.arm.com [10.1.194.81]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 1B5143F6C4; Tue, 12 Nov 2019 04:03:34 -0800 (PST) From: vincent.donnefort@arm.com To: linux-trace-devel@vger.kernel.org Cc: Vincent Donnefort Subject: [PATCH v2 1/2] trace-cmd: Enable kptr_restrict Date: Tue, 12 Nov 2019 12:03:26 +0000 Message-Id: <1573560207-52550-1-git-send-email-vincent.donnefort@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <20191111175203.252cc439@gandalf.local.home> References: <20191111175203.252cc439@gandalf.local.home> Sender: linux-trace-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org From: Vincent Donnefort kptr_restrict might prevent trace-cmd from accessing /proc/kallsyms, leading to a trace without the kernel function names resolved. Signed-off-by: Vincent Donnefort diff --git a/lib/trace-cmd/trace-output.c b/lib/trace-cmd/trace-output.c index 41932ee..be4d3f5 100644 --- a/lib/trace-cmd/trace-output.c +++ b/lib/trace-cmd/trace-output.c @@ -674,6 +674,46 @@ static int read_event_files(struct tracecmd_output *handle, return ret; } +#define KPTR_UNINITIALIZED 'X' + +static void set_proc_kptr_restrict(int reset) +{ + char *path = "/proc/sys/kernel/kptr_restrict"; + static char saved = KPTR_UNINITIALIZED; + int fd, ret = -1; + struct stat st; + char buf; + + if ((reset && saved == KPTR_UNINITIALIZED) || + (stat(path, &st) < 0)) + return; + + fd = open(path, O_RDONLY); + if (fd < 0) + goto err; + + if (reset) { + buf = saved; + } else { + if (read(fd, &buf, 1) < 0) + goto err; + saved = buf; + buf = '0'; + } + close(fd); + + fd = open(path, O_WRONLY); + if (fd < 0) + goto err; + if (write(fd, &buf, 1) > 0) + ret = 0; +err: + if (fd > 0) + close(fd); + if (ret) + warning("can't set kptr_restrict"); +} + static int read_proc_kallsyms(struct tracecmd_output *handle, const char *kallsyms) { @@ -698,12 +738,16 @@ static int read_proc_kallsyms(struct tracecmd_output *handle, endian4 = convert_endian_4(handle, size); if (do_write_check(handle, &endian4, 4)) return -1; + + set_proc_kptr_restrict(0); check_size = copy_file(handle, path); if (size != check_size) { errno = EINVAL; warning("error in size of file '%s'", path); + set_proc_kptr_restrict(1); return -1; } + set_proc_kptr_restrict(1); return 0; } -- 2.7.4