From 12653ec36112ab55fa06c01db7c4432653d30a8d Mon Sep 17 00:00:00 2001 From: Qu Wenruo <wqu@suse.com> Date: Fri, 19 Jul 2024 18:56:46 +0930 Subject: [PATCH] btrfs: avoid using fixed char array size for tree names MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [BUG] There is a bug report that using the latest trunk GCC 15, btrfs would cause unterminated-string-initialization warning: linux-6.6/fs/btrfs/print-tree.c:29:49: error: initializer-string for array of ‘char’ is too long [-Werror=unterminated-string-initialization] 29 | { BTRFS_BLOCK_GROUP_TREE_OBJECTID, "BLOCK_GROUP_TREE" }, | ^~~~~~~~~~~~~~~~~~ [CAUSE] To print tree names we have an array of root_name_map structure, which uses "char name[16];" to store the name string of a tree. But the following trees have names exactly at 16 chars length: - "BLOCK_GROUP_TREE" - "RAID_STRIPE_TREE" This means we will have no space for the terminating '\0', and can lead to unexpected access when printing the name. [FIX] Instead of "char name[16];" use "const char *" instead. Since the name strings are all read-only data, and are all NULL terminated by default, there is not much need to bother the length at all. Reported-by: Sam James <sam@gentoo.org> Reported-by: Alejandro Colomar <alx@kernel.org> Fixes: edde81f1abf29 ("btrfs: add raid stripe tree pretty printer") Fixes: 9c54e80ddc6bd ("btrfs: add code to support the block group root") CC: stable@vger.kernel.org # 6.1+ Suggested-by: Alejandro Colomar <alx@kernel.org> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Alejandro Colomar <alx@kernel.org> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> --- fs/btrfs/print-tree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/btrfs/print-tree.c b/fs/btrfs/print-tree.c index 32dcea662da3..fc821aa446f0 100644 --- a/fs/btrfs/print-tree.c +++ b/fs/btrfs/print-tree.c @@ -14,7 +14,7 @@ struct root_name_map { u64 id; - char name[16]; + const char *name; }; static const struct root_name_map root_map[] = {