[PATCH] netfs: Mark __nonstring lookup tables

[PATCH] netfs: Mark __nonstring lookup tables

[Kees Cook]

GCC 15's new -Wunterminated-string-initialization notices that the
character lookup tables "fscache_cache_states" and "fscache_cookie_states"
(which are not used as a C-String) need to be marked as "nonstring":

fs/netfs/fscache_cache.c:375:67: warning: initializer-string for array of 'char' truncates NUL terminator but destination lacks 'nonstring' attribute (6 chars into 5 available) [-Wunterminated-string-initialization]
  375 | static const char fscache_cache_states[NR__FSCACHE_CACHE_STATE] = "-PAEW";
      |                                                                   ^~~~~~~
fs/netfs/fscache_cookie.c:32:69: warning: initializer-string for array of 'char' truncates NUL terminator but destination lacks 'nonstring' attribute (11 chars into 10 available) [-Wunterminated-string-initialization]
   32 | static const char fscache_cookie_states[FSCACHE_COOKIE_STATE__NR] = "-LCAIFUWRD";
      |                                                                     ^~~~~~~~~~~~

Annotate the arrays.

Signed-off-by: Kees Cook <kees@kernel.org>
---
Cc: David Howells <dhowells@redhat.com>
Cc: Paulo Alcantara <pc@manguebit.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: netfs@lists.linux.dev
Cc: linux-fsdevel@vger.kernel.org
---
 fs/netfs/fscache_cache.c  | 2 +-
 fs/netfs/fscache_cookie.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/netfs/fscache_cache.c b/fs/netfs/fscache_cache.c
index 9397ed39b0b4..8f70f8da064b 100644
--- a/fs/netfs/fscache_cache.c
+++ b/fs/netfs/fscache_cache.c
@@ -372,7 +372,7 @@ void fscache_withdraw_cache(struct fscache_cache *cache)
 EXPORT_SYMBOL(fscache_withdraw_cache);
 
 #ifdef CONFIG_PROC_FS
-static const char fscache_cache_states[NR__FSCACHE_CACHE_STATE] = "-PAEW";
+static const char fscache_cache_states[NR__FSCACHE_CACHE_STATE] __nonstring = "-PAEW";
 
 /*
  * Generate a list of caches in /proc/fs/fscache/caches
diff --git a/fs/netfs/fscache_cookie.c b/fs/netfs/fscache_cookie.c
index d4d4b3a8b106..3d56fc73435f 100644
--- a/fs/netfs/fscache_cookie.c
+++ b/fs/netfs/fscache_cookie.c
@@ -29,7 +29,7 @@ static LIST_HEAD(fscache_cookie_lru);
 static DEFINE_SPINLOCK(fscache_cookie_lru_lock);
 DEFINE_TIMER(fscache_cookie_lru_timer, fscache_cookie_lru_timed_out);
 static DECLARE_WORK(fscache_cookie_lru_work, fscache_cookie_lru_worker);
-static const char fscache_cookie_states[FSCACHE_COOKIE_STATE__NR] = "-LCAIFUWRD";
+static const char fscache_cookie_states[FSCACHE_COOKIE_STATE__NR] __nonstring = "-LCAIFUWRD";
 static unsigned int fscache_lru_cookie_timeout = 10 * HZ;
 
 void fscache_print_cookie(struct fscache_cookie *cookie, char prefix)
-- 
2.34.1

Re: [PATCH] netfs: Mark __nonstring lookup tables

[Christian Brauner]

On Wed, 16 Apr 2025 15:16:55 -0700, Kees Cook wrote:
> GCC 15's new -Wunterminated-string-initialization notices that the
> character lookup tables "fscache_cache_states" and "fscache_cookie_states"
> (which are not used as a C-String) need to be marked as "nonstring":
> 
> fs/netfs/fscache_cache.c:375:67: warning: initializer-string for array of 'char' truncates NUL terminator but destination lacks 'nonstring' attribute (6 chars into 5 available) [-Wunterminated-string-initialization]
>   375 | static const char fscache_cache_states[NR__FSCACHE_CACHE_STATE] = "-PAEW";
>       |                                                                   ^~~~~~~
> fs/netfs/fscache_cookie.c:32:69: warning: initializer-string for array of 'char' truncates NUL terminator but destination lacks 'nonstring' attribute (11 chars into 10 available) [-Wunterminated-string-initialization]
>    32 | static const char fscache_cookie_states[FSCACHE_COOKIE_STATE__NR] = "-LCAIFUWRD";
>       |                                                                     ^~~~~~~~~~~~
> 
> [...]

Applied to the vfs.fixes branch of the vfs/vfs.git tree.
Patches in the vfs.fixes branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs.fixes

[1/1] netfs: Mark __nonstring lookup tables
      https://git.kernel.org/vfs/vfs/c/58db1c3cd0ce