| Message ID | b6633fbd1110ce2b5ff03ff9605f59e508ff31d0.1721380874.git.wqu@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] btrfs: avoid using fixed char array size for tree names | expand |
Hi Qu, On Fri, Jul 19, 2024 at 06:56:46PM GMT, Qu Wenruo wrote: > [BUG] > There is a bug report that using the latest trunk GCC, 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. LGTM. > Fixes: edde81f1abf29 ("btrfs: add raid stripe tree pretty printer") > Fixes: 9c54e80ddc6bd ("btrfs: add code to support the block group root") > Reported-by: Sam James <sam@gentoo.org> > Reported-by: Alejandro Colomar <alx@kernel.org> > Suggested-by: Alejandro Colomar <alx@kernel.org> > Signed-off-by: Qu Wenruo <wqu@suse.com> > --- > Changelog: > v2: > - Add all the needed tags > Especially for the two fixes tags. Thanks. > > 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[] = { LGTM. Thanks! I don't know the source enough to know if this affects anything else, but at face value, I'd say: Reviewed-by: Alejandro Colomar <alx@kernel.org> Have a lovely day! Alex > -- > 2.45.2 >
Looks good,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
On Fri, Jul 19, 2024 at 06:56:46PM +0930, Qu Wenruo wrote: > [BUG] > There is a bug report that using the latest trunk GCC, 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. > > Fixes: edde81f1abf29 ("btrfs: add raid stripe tree pretty printer") > Fixes: 9c54e80ddc6bd ("btrfs: add code to support the block group root") > Reported-by: Sam James <sam@gentoo.org> > Reported-by: Alejandro Colomar <alx@kernel.org> > Suggested-by: Alejandro Colomar <alx@kernel.org> > Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com>
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[] = {
[BUG] There is a bug report that using the latest trunk GCC, 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. Fixes: edde81f1abf29 ("btrfs: add raid stripe tree pretty printer") Fixes: 9c54e80ddc6bd ("btrfs: add code to support the block group root") Reported-by: Sam James <sam@gentoo.org> Reported-by: Alejandro Colomar <alx@kernel.org> Suggested-by: Alejandro Colomar <alx@kernel.org> Signed-off-by: Qu Wenruo <wqu@suse.com> --- Changelog: v2: - Add all the needed tags Especially for the two fixes tags. fs/btrfs/print-tree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)