From: Boris Burkov boris@bur.io
[ Upstream commit d6fe0c69b3aa5c985380b794bdf8e6e9b1811e60 ]
num_extent_folios() unconditionally calls folio_order() on eb->folios[0]. If that is NULL this will be a segfault. It is reasonable for it to return 0 as the number of folios in the eb when the first entry is NULL, so do that instead.
Reviewed-by: Qu Wenruo wqu@suse.com Signed-off-by: Boris Burkov boris@bur.io Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/extent_io.h | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h index 6c5328bfabc22..2aefc64cdd295 100644 --- a/fs/btrfs/extent_io.h +++ b/fs/btrfs/extent_io.h @@ -297,6 +297,8 @@ static inline int num_extent_pages(const struct extent_buffer *eb) */ static inline int num_extent_folios(const struct extent_buffer *eb) { + if (!eb->folios[0]) + return 0; if (folio_order(eb->folios[0])) return 1; return num_extent_pages(eb);