From 187c71f6ab439582c80433ef9e04f615b8c0f576 Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Wed, 18 Dec 2019 17:34:36 -0500 Subject: [PATCH] bcachefs: Fix a memory splat In __bch2_sb_field_resize, when a field's old a new size was 0, we were doing an invalid write just past the end of the superblock. Signed-off-by: Kent Overstreet Signed-off-by: Kent Overstreet --- fs/bcachefs/super-io.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/bcachefs/super-io.c b/fs/bcachefs/super-io.c index cd1aa3891c2e4..4c1e8571d8724 100644 --- a/fs/bcachefs/super-io.c +++ b/fs/bcachefs/super-io.c @@ -54,7 +54,9 @@ static struct bch_sb_field *__bch2_sb_field_resize(struct bch_sb_handle *sb, BUG_ON(get_order(__vstruct_bytes(struct bch_sb, sb_u64s)) > sb->page_order); - if (!f) { + if (!f && !u64s) { + /* nothing to do: */ + } else if (!f) { f = vstruct_last(sb->sb); memset(f, 0, sizeof(u64) * u64s); f->u64s = cpu_to_le32(u64s); -- 2.30.2