{"id":2225000,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2225000/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-cifs-client/patch/20260420083705.1009074-2-dhowells@redhat.com/","project":{"id":12,"url":"http://patchwork.ozlabs.org/api/1.1/projects/12/?format=json","name":"Linux CIFS Client","link_name":"linux-cifs-client","list_id":"linux-cifs.vger.kernel.org","list_email":"linux-cifs@vger.kernel.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20260420083705.1009074-2-dhowells@redhat.com>","date":"2026-04-20T08:36:52","name":"[01/11] netfs: Fix early put of sink folio in netfs_read_gaps()","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"02b4ca22d894b95b7d7d73fc5db8e868bda1aaae","submitter":{"id":59,"url":"http://patchwork.ozlabs.org/api/1.1/people/59/?format=json","name":"David Howells","email":"dhowells@redhat.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/linux-cifs-client/patch/20260420083705.1009074-2-dhowells@redhat.com/mbox/","series":[{"id":500568,"url":"http://patchwork.ozlabs.org/api/1.1/series/500568/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-cifs-client/list/?series=500568","date":"2026-04-20T08:36:52","name":"netfs: Further miscellaneous fixes","version":1,"mbox":"http://patchwork.ozlabs.org/series/500568/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2225000/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2225000/checks/","tags":{},"headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-cifs@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=LAAfxSn/;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c15:e001:75::12fc:5321; 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c=relaxed/relaxed; d=redhat.com;\n\ts=mimecast20190719; t=1776674245;\n\th=from:from:reply-to:subject:subject:date:date:message-id:message-id:\n\t to:to:cc:cc:mime-version:mime-version:\n\t content-transfer-encoding:content-transfer-encoding:\n\t in-reply-to:in-reply-to:references:references;\n\tbh=ksxJg5s1e4rqCiU0anjwW0Drg+bXTRaHFQWcy6sTuKQ=;\n\tb=LAAfxSn/3rU9Ivd58Hr6n1neexlCNwrE6inWPwdIFr1pHxnSRlNuuWj0eTLk96qosLeKDi\n\tzdCTuLvLa0QLqY8FJKWO8BAIQz3Dgoyckg4BksmXbIN9VXJITPFLO7nDEYij+xD4j7LC8i\n\tWIWg9CVy8q3gtTtDM3d6MIeEd62hNIg=","X-MC-Unique":"tjVoit6wNru8srkOeHIZeQ-1","X-Mimecast-MFC-AGG-ID":"tjVoit6wNru8srkOeHIZeQ_1776674239","From":"David Howells ","To":"Christian Brauner ","Cc":"David Howells ,\n\tPaulo Alcantara ,\n\tnetfs@lists.linux.dev,\n\tlinux-afs@lists.infradead.org,\n\tlinux-cifs@vger.kernel.org,\n\tceph-devel@vger.kernel.org,\n\tlinux-fsdevel@vger.kernel.org,\n\tlinux-kernel@vger.kernel.org,\n\tSteve French ,\n\tMatthew Wilcox ","Subject":"[PATCH 01/11] netfs: Fix early put of sink folio in netfs_read_gaps()","Date":"Mon, 20 Apr 2026 09:36:52 +0100","Message-ID":"<20260420083705.1009074-2-dhowells@redhat.com>","In-Reply-To":"<20260420083705.1009074-1-dhowells@redhat.com>","References":"<20260420083705.1009074-1-dhowells@redhat.com>","Precedence":"bulk","X-Mailing-List":"linux-cifs@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","X-Scanned-By":"MIMEDefang 3.0 on 10.30.177.17"},"content":"Fix netfs_read_gaps() to release the sink page it uses after waiting for\nthe request to complete. The way the sink page is used is that an\nITER_BVEC-class iterator is created that has the gaps from the target folio\nat either end, but has the sink page tiled over the middle so that a single\nread op can fill in both gaps.\n\nThe bug was found by KASAN detecting a UAF on the generic/075 xfstest in\nthe cifsd kernel thread that handles reception of data from the TCP socket:\n\n BUG: KASAN: use-after-free in _copy_to_iter+0x48a/0xa20\n Write of size 885 at addr ffff888107f92000 by task cifsd/1285\n CPU: 2 UID: 0 PID: 1285 Comm: cifsd Not tainted 7.0.0 #6 PREEMPT(lazy)\n Call Trace:\n dump_stack_lvl+0x5d/0x80\n print_report+0x17f/0x4f1\n kasan_report+0x100/0x1e0\n kasan_check_range+0x10f/0x1e0\n __asan_memcpy+0x3c/0x60\n _copy_to_iter+0x48a/0xa20\n __skb_datagram_iter+0x2c9/0x430\n skb_copy_datagram_iter+0x6e/0x160\n tcp_recvmsg_locked+0xce0/0x1130\n tcp_recvmsg+0xeb/0x300\n inet_recvmsg+0xcf/0x3a0\n sock_recvmsg+0xea/0x100\n cifs_readv_from_socket+0x3a6/0x4d0 [cifs]\n cifs_read_iter_from_socket+0xdd/0x130 [cifs]\n cifs_readv_receive+0xaad/0xb10 [cifs]\n cifs_demultiplex_thread+0x1148/0x1740 [cifs]\n kthread+0x1cf/0x210\n\nFixes: ee4cdf7ba857 (\"netfs: Speed up buffered reading\")\nReported-by: Steve French \nSigned-off-by: David Howells \ncc: Paulo Alcantara \ncc: Matthew Wilcox \ncc: netfs@lists.linux.dev\ncc: linux-fsdevel@vger.kernel.org\n---\n fs/netfs/buffered_read.c | 6 +++---\n 1 file changed, 3 insertions(+), 3 deletions(-)","diff":"diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c\nindex c23173a061e8..dc50690fdd44 100644\n--- a/fs/netfs/buffered_read.c\n+++ b/fs/netfs/buffered_read.c\n@@ -459,9 +459,6 @@ static int netfs_read_gaps(struct file *file, struct folio *folio)\n \n \tnetfs_read_to_pagecache(rreq, NULL);\n \n-\tif (sink)\n-\t\tfolio_put(sink);\n-\n \tret = netfs_wait_for_read(rreq);\n \tif (ret >= 0) {\n \t\tfolio_detach_private(folio);\n@@ -471,6 +468,9 @@ static int netfs_read_gaps(struct file *file, struct folio *folio)\n \t\tflush_dcache_folio(folio);\n \t\tfolio_mark_uptodate(folio);\n \t}\n+\n+\tif (sink)\n+\t\tfolio_put(sink);\n \tfolio_unlock(folio);\n \tnetfs_put_request(rreq, netfs_rreq_trace_put_return);\n \treturn ret < 0 ? ret : 0;\n","prefixes":["01/11"]}