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Commit 091e26df authored by Jan Kara's avatar Jan Kara Committed by Theodore Ts'o
Browse files

ext4: fix possible use-after-free with AIO 



Running AIO is pinning inode in memory using file reference. Once AIO
is completed using aio_complete(), file reference is put and inode can
be freed from memory. So we have to be sure that calling aio_complete()
is the last thing we do with the inode.

CC: stable@vger.kernel.org
Reviewed-by: default avatarCarlos Maiolino <cmaiolino@redhat.com>
Acked-by: default avatarJeff Moyer <jmoyer@redhat.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent b1deefc9

fs/ext4/inode.c

+1 −1
Original line number Diff line number Diff line
@@ -2850,9 +2850,9 @@ static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset, 
	if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {

		ext4_free_io_end(io_end);

out:

		inode_dio_done(inode);

		if (is_async)

			aio_complete(iocb, ret, 0);

		inode_dio_done(inode);

		return;

	}

fs/ext4/page-io.c

+4 −5
Original line number Diff line number Diff line
@@ -102,14 +102,13 @@ static int ext4_end_io(ext4_io_end_t *io) 
			 "(inode %lu, offset %llu, size %zd, error %d)",

			 inode->i_ino, offset, size, ret);

	}

	if (io->iocb)

		aio_complete(io->iocb, io->result, 0);



	if (io->flag & EXT4_IO_END_DIRECT)

		inode_dio_done(inode);

	/* Wake up anyone waiting on unwritten extent conversion */

	if (atomic_dec_and_test(&EXT4_I(inode)->i_unwritten))

		wake_up_all(ext4_ioend_wq(inode));

	if (io->flag & EXT4_IO_END_DIRECT)

		inode_dio_done(inode);

	if (io->iocb)

		aio_complete(io->iocb, io->result, 0);

	return ret;

}