iomap: Fix use-after-free error in page_done callback
In iomap_write_end, we're not holding a page reference anymore when
calling the page_done callback, but the callback needs that reference to
access the page. To fix that, move the put_page call in
__generic_write_end into the callers of __generic_write_end. Then, in
iomap_write_end, put the page after calling the page_done callback.
Reported-by: Jan Kara <jack@suse.cz>
Fixes: 63899c6f8851 ("iomap: add a page_done callback")
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
diff --git a/fs/buffer.c b/fs/buffer.c
index e0d4c6a..0faa41fb 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2104,7 +2104,6 @@ void __generic_write_end(struct inode *inode, loff_t pos, unsigned copied,
}
unlock_page(page);
- put_page(page);
if (old_size < pos)
pagecache_isize_extended(inode, old_size, pos);
@@ -2160,6 +2159,7 @@ int generic_write_end(struct file *file, struct address_space *mapping,
{
copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
__generic_write_end(mapping->host, pos, copied, page);
+ put_page(page);
return copied;
}
EXPORT_SYMBOL(generic_write_end);