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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 85DE6C433EF for ; Fri, 28 Jan 2022 20:40:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230151AbiA1Uk3 (ORCPT ); Fri, 28 Jan 2022 15:40:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43798 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351300AbiA1Ujz (ORCPT ); Fri, 28 Jan 2022 15:39:55 -0500 Received: from mail-pj1-x1029.google.com (mail-pj1-x1029.google.com [IPv6:2607:f8b0:4864:20::1029]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8DC2FC061755 for ; Fri, 28 Jan 2022 12:39:54 -0800 (PST) Received: by mail-pj1-x1029.google.com with SMTP id s61-20020a17090a69c300b001b4d0427ea2so11902342pjj.4 for ; Fri, 28 Jan 2022 12:39:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=BY01qBOdjhAiiWa9uW1+iF389ifyWGwXOZ9xdr+rmug=; b=BH/szD6siBQk1860WgLRHuVgS9NK22OdxswVJJSSTpe4HGziKWTdpaIJx2LVb/rXDX Ci7DSCWo9dO/0/lrBOGIjG8c91iIHAkf7bklmi6IebAztyL+f+mU5XUK5a9MQRmzna1J 9iZHv0qjHuWX0P95440lpoQztT6kcHiy2IzZF3xdvwF0dlcqffD5I/UdoR9rId1ym/Fv YI4tItrur8C2GtNOMImHO3sIfYj/QxEniOoDCvkVKTw02gZftVhDU8SsKrjpK5AQEf4K 6rdkbgppGu5tQZtnJb4va+BQVV6vNFkykMUlT8AY61N8bz+tjhn0LeICGHEH9o21lZoR tz7g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-transfer-encoding; bh=BY01qBOdjhAiiWa9uW1+iF389ifyWGwXOZ9xdr+rmug=; b=kCv6D8+mrpA7Gon0m16j0acHVnS47EELWkZcMNKRG5ql7RW1cT85ktAlblGJG8CqUf wRdUVfKZqNZ8JA5gl1mWRHFMizYFoUvHcsSUxfDKlwWHKL9cUbaNBP5lbYP4sfD9eOvU GtNNcGlm+dA2ZF2KFHsGNnfMjVNBm8jV7wH9ir0pacLJ7Lk/YVQF38O1Y+dC7RUUHDDe xM70RF9dCJ0WEKM5+godSlZKJ0NKuZ3aWV0zsEIBtVlCLS8h6uVeUeQOv714RlFMjkVR BCAIDxhUAN4+OH24MD7wh1qbQL0m8EtOCJTU30Cxog8BsXtviydAwIpjEsZJOCPNK/gb kk9Q== X-Gm-Message-State: AOAM530pM4NccuUVglv51jUT2u0ShqJCctFKmqG6cqXWNDopp6bbQrEz +1Ib+yZVaQTHJShJhHFmrsg= X-Google-Smtp-Source: ABdhPJwgr6KUeRY0eaPfaew+ad43L7zs2q+PVU48ZWEnOX3MI42QJTTibPPW9E1dIOHVxRrzeFyZKw== X-Received: by 2002:a17:90b:4a8e:: with SMTP id lp14mr21643443pjb.75.1643402394057; Fri, 28 Jan 2022 12:39:54 -0800 (PST) Received: from balhae.hsd1.ca.comcast.net ([2601:647:4800:c6f0:f13b:bc2c:fac:4a86]) by smtp.gmail.com with ESMTPSA id k3sm11235428pfu.180.2022.01.28.12.39.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 28 Jan 2022 12:39:53 -0800 (PST) Sender: Namhyung Kim From: Namhyung Kim To: Arnaldo Carvalho de Melo , Jiri Olsa Cc: Ingo Molnar , Peter Zijlstra , LKML , Andi Kleen , Ian Rogers Subject: [PATCH 1/3] perf tools: Try chroot'ed filename when opening dso/symbol Date: Fri, 28 Jan 2022 12:39:48 -0800 Message-Id: <20220128203950.3371061-2-namhyung@kernel.org> X-Mailer: git-send-email 2.35.0.rc2.247.g8bbb082509-goog In-Reply-To: <20220128203950.3371061-1-namhyung@kernel.org> References: <20220128203950.3371061-1-namhyung@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently it doesn't handle tasks in chroot properly. As filenames in MMAP records base on their root directory, it's different than what perf tool can see from outside. Add filename_with_chroot() helper to deal with those cases. The function returns a new filename only if it's in a different root directory. Since it needs to access /proc for the process, it only works until the task exits. With this change, I can see symbols in my program like below. # perf record -o- chroot myroot myprog 3 | perf report -i- ... # # Overhead Command Shared Object Symbol # ........ ....... ................. ............................. # 99.83% myprog myprog [.] loop 0.04% chroot [kernel.kallsyms] [k] fxregs_fixup 0.04% chroot [kernel.kallsyms] [k] rsm_load_seg_32 ... Signed-off-by: Namhyung Kim --- tools/perf/util/dso.c | 15 +++++++++++++-- tools/perf/util/dsos.c | 13 +++++++++++++ tools/perf/util/symbol.c | 10 ++++++++++ tools/perf/util/util.c | 31 +++++++++++++++++++++++++++++++ tools/perf/util/util.h | 2 ++ 5 files changed, 69 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c index 9cc8a1772b4b..5ac13958d1bd 100644 --- a/tools/perf/util/dso.c +++ b/tools/perf/util/dso.c @@ -508,8 +508,19 @@ static int __open_dso(struct dso *dso, struct machine *machine) root_dir, name, PATH_MAX)) goto out; - if (!is_regular_file(name)) - goto out; + if (!is_regular_file(name)) { + char *new_name; + + if (errno != ENOENT || dso->nsinfo == NULL) + goto out; + + new_name = filename_with_chroot(dso->nsinfo->pid, name); + if (!new_name) + goto out; + + free(name); + name = new_name; + } if (dso__needs_decompress(dso)) { char newpath[KMOD_DECOMP_LEN]; diff --git a/tools/perf/util/dsos.c b/tools/perf/util/dsos.c index 183a81d5b2f9..b97366f77bbf 100644 --- a/tools/perf/util/dsos.c +++ b/tools/perf/util/dsos.c @@ -2,12 +2,15 @@ #include "debug.h" #include "dsos.h" #include "dso.h" +#include "util.h" #include "vdso.h" #include "namespaces.h" +#include #include #include #include #include // filename__read_build_id +#include static int __dso_id__cmp(struct dso_id *a, struct dso_id *b) { @@ -76,6 +79,16 @@ bool __dsos__read_build_ids(struct list_head *head, bool with_hits) if (filename__read_build_id(pos->long_name, &pos->bid) > 0) { have_build_id = true; pos->has_build_id = true; + } else if (errno == ENOENT && pos->nsinfo) { + char *new_name = filename_with_chroot(pos->nsinfo->pid, + pos->long_name); + + if (new_name && filename__read_build_id(new_name, + &pos->bid) > 0) { + have_build_id = true; + pos->has_build_id = true; + } + free(new_name); } nsinfo__mountns_exit(&nsc); } diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index b2ed3140a1fa..34302c61d36b 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -1864,6 +1864,16 @@ int dso__load(struct dso *dso, struct map *map) nsinfo__mountns_exit(&nsc); is_reg = is_regular_file(name); + if (!is_reg && errno == ENOENT && dso->nsinfo) { + char *new_name = filename_with_chroot(dso->nsinfo->pid, + name); + if (new_name) { + is_reg = is_regular_file(new_name); + strlcpy(name, new_name, PATH_MAX); + free(new_name); + } + } + #ifdef HAVE_LIBBFD_SUPPORT if (is_reg) bfdrc = dso__load_bfd_symbols(dso, name); diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c index fb4f6616b5fa..f8571a66d063 100644 --- a/tools/perf/util/util.c +++ b/tools/perf/util/util.c @@ -431,3 +431,34 @@ void perf_debuginfod_setup(struct perf_debuginfod *di) pr_debug("DEBUGINFOD_URLS=%s\n", getenv("DEBUGINFOD_URLS")); } + +/* + * Return a new filename prepended with task's root directory if it's in + * a chroot. Callers should free the returned string. + */ +char *filename_with_chroot(int pid, const char *filename) +{ + char buf[PATH_MAX]; + char proc_root[32]; + char *new_name = NULL; + int ret; + + scnprintf(proc_root, sizeof(proc_root), "/proc/%d/root", pid); + ret = readlink(proc_root, buf, sizeof(buf) - 1); + if (ret <= 0) + return NULL; + + /* readlink(2) does not append a null byte to buf */ + buf[ret] = '\0'; + + if (!strcmp(buf, "/")) + return NULL; + + if (strstr(buf, "(deleted)")) + return NULL; + + if (asprintf(&new_name, "%s/%s", buf, filename) < 0) + return NULL; + + return new_name; +} diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h index 7b625cbd2dd8..0f78f1e7782d 100644 --- a/tools/perf/util/util.h +++ b/tools/perf/util/util.h @@ -77,4 +77,6 @@ struct perf_debuginfod { bool set; }; void perf_debuginfod_setup(struct perf_debuginfod *di); + +char *filename_with_chroot(int pid, const char *filename); #endif /* GIT_COMPAT_UTIL_H */ -- 2.35.0.rc2.247.g8bbb082509-goog