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Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <6a19f098.abb04025.19af7b.0003.GAE@google.com> References: <6a19f098.abb04025.19af7b.0003.GAE@google.com> To: syzbot Cc: dhowells@redhat.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, netfs@lists.linux.dev, pc@manguebit.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [netfs?] KASAN: slab-use-after-free Read in netfs_unbuffered_write Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <3106405.1782391857.1@warthog.procyon.org.uk> Content-Transfer-Encoding: quoted-printable Date: Thu, 25 Jun 2026 13:50:57 +0100 Message-ID: <3106406.1782391857@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.gi= t 8fde5d1d47f6 diff --git a/fs/netfs/direct_write.c b/fs/netfs/direct_write.c index 25f8ceb15fad..c16fbad286a1 100644 --- a/fs/netfs/direct_write.c +++ b/fs/netfs/direct_write.c @@ -166,13 +166,16 @@ static int netfs_unbuffered_write(struct netfs_io_re= quest *wreq) */ subreq->error =3D -EAGAIN; trace_netfs_sreq(subreq, netfs_sreq_trace_retry); - if (subreq->transferred > 0) + if (subreq->transferred > 0) { iov_iter_advance(&wreq->buffer.iter, subreq->transferred); + wreq->transferred +=3D subreq->transferred; + } = if (stream->source =3D=3D NETFS_UPLOAD_TO_SERVER && wreq->netfs_ops->retry_request) wreq->netfs_ops->retry_request(wreq, stream); = + __clear_bit(NETFS_SREQ_MADE_PROGRESS, &subreq->flags); __clear_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags); __clear_bit(NETFS_SREQ_BOUNDARY, &subreq->flags); __clear_bit(NETFS_SREQ_FAILED, &subreq->flags); @@ -186,17 +189,10 @@ static int netfs_unbuffered_write(struct netfs_io_re= quest *wreq) = netfs_get_subrequest(subreq, netfs_sreq_trace_get_resubmit); = - if (stream->prepare_write) { + if (stream->prepare_write) stream->prepare_write(subreq); - __set_bit(NETFS_SREQ_IN_PROGRESS, &subreq->flags); - netfs_stat(&netfs_n_wh_retry_write_subreq); - } else { - struct iov_iter source; - - netfs_reset_iter(subreq); - source =3D subreq->io_iter; - netfs_reissue_write(stream, subreq, &source); - } + __set_bit(NETFS_SREQ_IN_PROGRESS, &subreq->flags); + netfs_stat(&netfs_n_wh_retry_write_subreq); } = netfs_unbuffered_write_done(wreq);