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=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 03877C2D0E4 for ; Tue, 17 Nov 2020 13:16:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A985B24631 for ; Tue, 17 Nov 2020 13:16:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="Ey7CQmpd" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730343AbgKQNQh (ORCPT ); Tue, 17 Nov 2020 08:16:37 -0500 Received: from mail.kernel.org ([198.145.29.99]:48142 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730294AbgKQNQW (ORCPT ); Tue, 17 Nov 2020 08:16:22 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7354E206D5; Tue, 17 Nov 2020 13:16:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605618981; bh=RQ1kzh+Mlqyc2N2MBby52SnnpV173ppyW1s2kdtnH4M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ey7CQmpddw3J2mGx3Nez+az9oRPoJ5u5ppxmgwNRjsfWfs2DsH3QsRNuCGiz4ippl LMPXL2Vc30nMggI4gEj52PlisLDqPcvPzpWHd8OKH+Ct9LNHYaZ5JoMhMIMEd4D6k0 zxFD3aQb+Odxjyn7o35cp38wfO97GUONL0kmGyOE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Miklos Szeredi , Song Liu , "Peter Zijlstra (Intel)" , kernel-team@fb.com, Alexander Shishkin , Arnaldo Carvalho de Melo , Jiri Olsa , Linus Torvalds , Stephane Eranian , Thomas Gleixner , Vince Weaver , Ingo Molnar , Sudip Mukherjee Subject: [PATCH 4.14 66/85] perf/core: Fix bad use of igrab() Date: Tue, 17 Nov 2020 14:05:35 +0100 Message-Id: <20201117122114.261555116@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201117122111.018425544@linuxfoundation.org> References: <20201117122111.018425544@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Song Liu commit 9511bce9fe8e5e6c0f923c09243a713eba560141 upstream As Miklos reported and suggested: "This pattern repeats two times in trace_uprobe.c and in kernel/events/core.c as well: ret = kern_path(filename, LOOKUP_FOLLOW, &path); if (ret) goto fail_address_parse; inode = igrab(d_inode(path.dentry)); path_put(&path); And it's wrong. You can only hold a reference to the inode if you have an active ref to the superblock as well (which is normally through path.mnt) or holding s_umount. This way unmounting the containing filesystem while the tracepoint is active will give you the "VFS: Busy inodes after unmount..." message and a crash when the inode is finally put. Solution: store path instead of inode." This patch fixes the issue in kernel/event/core.c. Reviewed-and-tested-by: Alexander Shishkin Reported-by: Miklos Szeredi Signed-off-by: Song Liu Signed-off-by: Peter Zijlstra (Intel) Cc: Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Fixes: 375637bc5249 ("perf/core: Introduce address range filtering") Link: http://lkml.kernel.org/r/20180418062907.3210386-2-songliubraving@fb.com Signed-off-by: Ingo Molnar Signed-off-by: Sudip Mukherjee Signed-off-by: Greg Kroah-Hartman --- arch/x86/events/intel/pt.c | 4 ++-- include/linux/perf_event.h | 2 +- kernel/events/core.c | 21 +++++++++------------ 3 files changed, 12 insertions(+), 15 deletions(-) --- a/arch/x86/events/intel/pt.c +++ b/arch/x86/events/intel/pt.c @@ -1190,7 +1190,7 @@ static int pt_event_addr_filters_validat if (!filter->range || !filter->size) return -EOPNOTSUPP; - if (!filter->inode) { + if (!filter->path.dentry) { if (!valid_kernel_ip(filter->offset)) return -EINVAL; @@ -1217,7 +1217,7 @@ static void pt_event_addr_filters_sync(s return; list_for_each_entry(filter, &head->list, entry) { - if (filter->inode && !offs[range]) { + if (filter->path.dentry && !offs[range]) { msr_a = msr_b = 0; } else { /* apply the offset */ --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -466,7 +466,7 @@ struct pmu { */ struct perf_addr_filter { struct list_head entry; - struct inode *inode; + struct path path; unsigned long offset; unsigned long size; unsigned int range : 1, --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6450,7 +6450,7 @@ static void perf_event_addr_filters_exec raw_spin_lock_irqsave(&ifh->lock, flags); list_for_each_entry(filter, &ifh->list, entry) { - if (filter->inode) { + if (filter->path.dentry) { event->addr_filters_offs[count] = 0; restart++; } @@ -7124,7 +7124,7 @@ static bool perf_addr_filter_match(struc struct file *file, unsigned long offset, unsigned long size) { - if (filter->inode != file_inode(file)) + if (d_inode(filter->path.dentry) != file_inode(file)) return false; if (filter->offset > offset + size) @@ -8345,8 +8345,7 @@ static void free_filters_list(struct lis struct perf_addr_filter *filter, *iter; list_for_each_entry_safe(filter, iter, filters, entry) { - if (filter->inode) - iput(filter->inode); + path_put(&filter->path); list_del(&filter->entry); kfree(filter); } @@ -8443,7 +8442,7 @@ static void perf_event_addr_filters_appl * Adjust base offset if the filter is associated to a binary * that needs to be mapped: */ - if (filter->inode) + if (filter->path.dentry) event->addr_filters_offs[count] = perf_addr_filter_apply(filter, mm); @@ -8516,7 +8515,6 @@ perf_event_parse_addr_filter(struct perf { struct perf_addr_filter *filter = NULL; char *start, *orig, *filename = NULL; - struct path path; substring_t args[MAX_OPT_ARGS]; int state = IF_STATE_ACTION, token; unsigned int kernel = 0; @@ -8620,19 +8618,18 @@ perf_event_parse_addr_filter(struct perf goto fail_free_name; /* look up the path and grab its inode */ - ret = kern_path(filename, LOOKUP_FOLLOW, &path); + ret = kern_path(filename, LOOKUP_FOLLOW, + &filter->path); if (ret) goto fail_free_name; - filter->inode = igrab(d_inode(path.dentry)); - path_put(&path); kfree(filename); filename = NULL; ret = -EINVAL; - if (!filter->inode || - !S_ISREG(filter->inode->i_mode)) - /* free_filters_list() will iput() */ + if (!filter->path.dentry || + !S_ISREG(d_inode(filter->path.dentry) + ->i_mode)) goto fail; event->addr_filters.nr_file_filters++;