KMSAN reported a use of uninitialized value in `__is_extent_mergeable()` and `__is_back_mergeable()` via the read extent tree path.
The root cause is that `get_read_extent_info()` only initializes three fields (`fofs`, `blk`, `len`) of `struct extent_info`, leaving the remaining fields uninitialized. This leads to undefined behavior when those fields are accessed later, especially during extent merging. Fix it by zero-initializing the `extent_info` struct before population. Reported-by: syzbot+b8c1d60e95df65e82...@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=b8c1d60e95df65e827d4 Fixes: 94afd6d6e525 ("f2fs: extent cache: support unaligned extent") Reviewed-by: Chao Yu <c...@kernel.org> Signed-off-by: Abinash Singh <abinashsinghlalo...@gmail.com> --- v4 : Added Reviewed-by and Corrected Fixes --- fs/f2fs/extent_cache.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c index cfe925a3d555..4ce19a310f38 100644 --- a/fs/f2fs/extent_cache.c +++ b/fs/f2fs/extent_cache.c @@ -414,7 +414,7 @@ void f2fs_init_read_extent_tree(struct inode *inode, struct folio *ifolio) struct f2fs_extent *i_ext = &F2FS_INODE(&ifolio->page)->i_ext; struct extent_tree *et; struct extent_node *en; - struct extent_info ei; + struct extent_info ei = {0}; if (!__may_extent_tree(inode, EX_READ)) { /* drop largest read extent */ -- 2.43.0 _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
