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Message-ID: <6724e790.050a0220.35b515.0172.GAE@google.com>
Date: Fri, 01 Nov 2024 07:37:04 -0700
From: syzbot <syzbot+404b4b745080b6210c6c@...kaller.appspotmail.com>
To: linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] Re: kernel BUG in iov_iter_revert (2)
For archival purposes, forwarding an incoming command email to
linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com.
***
Subject: Re: kernel BUG in iov_iter_revert (2)
Author: dmantipov@...dex.ru
#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 6c52d4da1c742cd01a797a4d0a2d3c5a60dc9bfe
diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c
index af46a598f4d7..706862094c49 100644
--- a/fs/netfs/buffered_read.c
+++ b/fs/netfs/buffered_read.c
@@ -174,6 +174,21 @@ static ssize_t netfs_prepare_read_iterator(struct netfs_io_subrequest *subreq)
return subreq->len;
}
+/* Wrap the above by handling possible -ENOMEM and
+ * marking the corresponding subrequest as cancelled.
+ */
+static inline ssize_t netfs_wrap_read_iterator(struct netfs_io_subrequest *subreq)
+{
+ struct netfs_io_request *rreq = subreq->rreq;
+ ssize_t slice = netfs_prepare_read_iterator(subreq);
+
+ if (unlikely(slice < 0)) {
+ atomic_dec(&rreq->nr_outstanding);
+ netfs_put_subrequest(subreq, false, netfs_sreq_trace_put_cancel);
+ }
+ return slice;
+}
+
static enum netfs_io_source netfs_cache_prepare_read(struct netfs_io_request *rreq,
struct netfs_io_subrequest *subreq,
loff_t i_size)
@@ -284,10 +299,8 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq)
trace_netfs_sreq(subreq, netfs_sreq_trace_prepare);
}
- slice = netfs_prepare_read_iterator(subreq);
- if (slice < 0) {
- atomic_dec(&rreq->nr_outstanding);
- netfs_put_subrequest(subreq, false, netfs_sreq_trace_put_cancel);
+ slice = netfs_wrap_read_iterator(subreq);
+ if (unlikely(slice < 0)) {
ret = slice;
break;
}
@@ -301,7 +314,11 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq)
subreq->source = NETFS_FILL_WITH_ZEROES;
trace_netfs_sreq(subreq, netfs_sreq_trace_submit);
netfs_stat(&netfs_n_rh_zero);
- slice = netfs_prepare_read_iterator(subreq);
+ slice = netfs_wrap_read_iterator(subreq);
+ if (unlikely(slice < 0)) {
+ ret = slice;
+ break;
+ }
__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
netfs_read_subreq_terminated(subreq, 0, false);
goto done;
@@ -309,7 +326,11 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq)
if (source == NETFS_READ_FROM_CACHE) {
trace_netfs_sreq(subreq, netfs_sreq_trace_submit);
- slice = netfs_prepare_read_iterator(subreq);
+ slice = netfs_wrap_read_iterator(subreq);
+ if (unlikely(slice < 0)) {
+ ret = slice;
+ break;
+ }
netfs_read_cache_to_pagecache(rreq, subreq);
goto done;
}
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