From: Miklos Szeredi <miklos@szeredi.hu>
To: syzbot <syzbot+9331a354f4f624a52a55@syzkaller.appspotmail.com>
Cc: Jiufei Xue <jiufei.xue@linux.alibaba.com>,
linux-kernel@vger.kernel.org,
overlayfs <linux-unionfs@vger.kernel.org>,
Miklos Szeredi <mszeredi@redhat.com>,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>
Subject: Re: WARNING: lock held when returning to user space in ovl_write_iter
Date: Fri, 13 Mar 2020 09:53:42 +0100 [thread overview]
Message-ID: <CAJfpegtd603jRNKnwFdNw4HffC7nj08YzWOrm3x=mf0ZwHzoOw@mail.gmail.com> (raw)
In-Reply-To: <000000000000cc1faf059fcfdc73@google.com>
[-- Attachment #1: Type: text/plain, Size: 85 bytes --]
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
63623fd4
[-- Attachment #2: ovl-fix-lockdep-warning-for-async-write.patch --]
[-- Type: text/x-patch, Size: 822 bytes --]
---
fs/overlayfs/file.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -244,6 +244,9 @@ static void ovl_aio_cleanup_handler(stru
if (iocb->ki_flags & IOCB_WRITE) {
struct inode *inode = file_inode(orig_iocb->ki_filp);
+ /* Actually acquired in ovl_write_iter() */
+ __sb_writers_acquired(file_inode(iocb->ki_filp)->i_sb,
+ SB_FREEZE_WRITE);
file_end_write(iocb->ki_filp);
ovl_copyattr(ovl_inode_real(inode), inode);
}
@@ -346,6 +349,9 @@ static ssize_t ovl_write_iter(struct kio
goto out;
file_start_write(real.file);
+ /* Pacify lockdep, same trick as done in aio_write() */
+ __sb_writers_release(file_inode(real.file)->i_sb,
+ SB_FREEZE_WRITE);
aio_req->fd = real;
real.flags = 0;
aio_req->orig_iocb = iocb;
prev parent reply other threads:[~2020-03-13 8:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-01 19:13 WARNING: lock held when returning to user space in ovl_write_iter syzbot
2020-03-12 15:30 ` Miklos Szeredi
2020-03-12 18:35 ` syzbot
2020-03-13 8:53 ` Miklos Szeredi [this message]
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