From d6fe0c69b3aa5c985380b794bdf8e6e9b1811e60 Mon Sep 17 00:00:00 2001 From: Boris Burkov Date: Fri, 25 Apr 2025 12:47:50 -0700 Subject: [PATCH] btrfs: handle empty eb->folios in num_extent_folios() 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 Signed-off-by: Boris Burkov Reviewed-by: David Sterba Signed-off-by: David Sterba --- 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 2e261892c7bc..f5b28b5c4908 100644 --- a/fs/btrfs/extent_io.h +++ b/fs/btrfs/extent_io.h @@ -298,6 +298,8 @@ static inline int __pure num_extent_pages(const struct extent_buffer *eb) */ static inline int __pure 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);