From: Miklos Szeredi Date: Fri, 13 Mar 2020 14:42:20 +0000 (+0100) Subject: ovl: fix lockdep warning for async write X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=c853680453ac235e9010987a8bdaaba0e116d3c8;p=linux.git ovl: fix lockdep warning for async write Lockdep reports "WARNING: lock held when returning to user space!" due to async write holding freeze lock over the write. Apparently aio.c already deals with this by lying to lockdep about the state of the lock. Do the same here. No need to check for S_IFREG() here since these file ops are regular-only. Reported-by: syzbot+9331a354f4f624a52a55@syzkaller.appspotmail.com Fixes: 2406a307ac7d ("ovl: implement async IO routines") Signed-off-by: Miklos Szeredi --- diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c index a5317216de736..87c362f65448b 100644 --- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -244,6 +244,9 @@ static void ovl_aio_cleanup_handler(struct ovl_aio_req *aio_req) 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 kiocb *iocb, struct iov_iter *iter) 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;