ovl: fix lockdep warning for async write (c8536804) · Commits · 戴 / test

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: ("ovl: implement async IO routines") Signed-off-by:

Miklos Szeredi <mszeredi@redhat.com>

fs/overlayfs/file.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -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;

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