From patchwork Tue Nov 21 23:10:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 168030 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:612c:2b07:b0:403:3b70:6f57 with SMTP id io7csp972027vqb; Tue, 21 Nov 2023 15:12:04 -0800 (PST) X-Google-Smtp-Source: AGHT+IHb+FnLGCAFPlTEDNxlRqBMp0OZU8EQ2WTl81KlfbUvd0QfGLarPziJcKBXoH78GbBdXsME X-Received: by 2002:a05:6a00:2314:b0:6be:43f8:4e0b with SMTP id h20-20020a056a00231400b006be43f84e0bmr708956pfh.24.1700608323901; Tue, 21 Nov 2023 15:12:03 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1700608323; cv=none; d=google.com; s=arc-20160816; b=dsbdb0TskJmo6pLaCY4WRmNkRnByzrq2TnpLNMr18jPd3oq/WiHUjQUIbZJEZ/+keK 6EBbf2ogM9udN9gVNA0tOuM/en8eDpjPpXTsjKlXuHciJGJmapfoIhz99stINNRcIpzm awW2vE9PQLXiws7SqJUltoUqBnO+Tg9tqQ8qTN5ZjtHQb2pREgiz5uuMjEiA+aDTfF+u VcCGO8hIxByGg/rSm2I9pKIk/HP5l/vazdjq4oz2ZgXAaFl+EktdXuIZ3ohJn36h6Hah tBFEhqS/4jEHt+2bBwzcXv9nKP40HKQfn3qjRRBYjeXx+9zy5K1D6xH+MyTXYT/4Bwaa Fgyw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:mime-version:references:subject:cc:to:from:date :user-agent:message-id; bh=MwXSnjnRJxRk/rq6PM4P3sKYFnyaqjjrtTHRJwr4Ypc=; fh=v5d2iK8lt4G1vkplZbghBt7rCstLvm5F4A2+SX42VNY=; b=hrKLMHNR6Xn4UHwNPpAMuq3Dc63T3uXqzd33oV5F8ybLWZuWQV8XvgpdiBnPpIdakY uYFQzUyY7oYksmtBGveJBghqYgDdYwCheipqTGA9g3xNlViR1FL2VG9fan+O3YFbYaWF 4LCUH+MMUS/ixE8TSp2+rn/j/GzdQF0Szg7fjujNskZUwEFVurMUOuX/uXjQLmqn6khS noTACZKNnpEKwQzomyZeZwa+VgIF7yTZfClksJzdlko29/ywp+Z3xK1rtjzUBF5xLgcN ymxLhiVKnXT+PQP2h5w/eA+y9wvGdLQdVO3NARtBNbMmMszuZGUnPdjWBm4SXpdZRC3h Wigw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:3 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from lipwig.vger.email (lipwig.vger.email. [2620:137:e000::3:3]) by mx.google.com with ESMTPS id f13-20020a056a0022cd00b006b7b42fe43asi11831655pfj.185.2023.11.21.15.12.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Nov 2023 15:12:03 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:3 as permitted sender) client-ip=2620:137:e000::3:3; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:3 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by lipwig.vger.email (Postfix) with ESMTP id 05E23817C1D2; Tue, 21 Nov 2023 15:11:07 -0800 (PST) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.11 at lipwig.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234887AbjKUXLE (ORCPT + 99 others); Tue, 21 Nov 2023 18:11:04 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54954 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229527AbjKUXLA (ORCPT ); Tue, 21 Nov 2023 18:11:00 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B1ED110C for ; Tue, 21 Nov 2023 15:10:56 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 58720C433C9; Tue, 21 Nov 2023 23:10:56 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.97-RC3) (envelope-from ) id 1r5Ztg-00000002dDc-27wd; Tue, 21 Nov 2023 18:11:12 -0500 Message-ID: <20231121231112.373501894@goodmis.org> User-Agent: quilt/0.67 Date: Tue, 21 Nov 2023 18:10:04 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Andrew Morton Subject: [PATCH 1/4] eventfs: Use GFP_NOFS for allocation when eventfs_mutex is held References: <20231121231003.516999942@goodmis.org> MIME-Version: 1.0 X-Spam-Status: No, score=-0.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lipwig.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (lipwig.vger.email [0.0.0.0]); Tue, 21 Nov 2023 15:11:07 -0800 (PST) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1783217073899449661 X-GMAIL-MSGID: 1783217073899449661 From: "Steven Rostedt (Google)" If memory reclaim happens, it can reclaim file system pages. The file system pages from eventfs may take the eventfs_mutex on reclaim. This means that allocation while holding the eventfs_mutex must not call into filesystem reclaim. A lockdep splat uncovered this. Fixes: 28e12c09f5aa0 ("eventfs: Save ownership and mode") Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode") Reported-by: Mark Rutland Signed-off-by: Steven Rostedt (Google) --- fs/tracefs/event_inode.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c index 3eb6c622a74d..56d192f0ead8 100644 --- a/fs/tracefs/event_inode.c +++ b/fs/tracefs/event_inode.c @@ -95,7 +95,7 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry, if (!(dentry->d_inode->i_mode & S_IFDIR)) { if (!ei->entry_attrs) { ei->entry_attrs = kzalloc(sizeof(*ei->entry_attrs) * ei->nr_entries, - GFP_KERNEL); + GFP_NOFS); if (!ei->entry_attrs) { ret = -ENOMEM; goto out; @@ -627,7 +627,7 @@ static int add_dentries(struct dentry ***dentries, struct dentry *d, int cnt) { struct dentry **tmp; - tmp = krealloc(*dentries, sizeof(d) * (cnt + 2), GFP_KERNEL); + tmp = krealloc(*dentries, sizeof(d) * (cnt + 2), GFP_NOFS); if (!tmp) return -1; tmp[cnt] = d;