Re: [PATCH v3 1/3] NFSD: Add a key for signing filehandles

[kernel test robot <lkp@intel.com>]

Hi Benjamin,

kernel test robot noticed the following build warnings:

[auto build test WARNING on dabff11003f9aaf293bd8f907a62f3366bd5e65f]

url:    https://github.com/intel-lab-lkp/linux/commits/Benjamin-Coddington/NFSD-Add-a-key-for-signing-filehandles/20260203-002703
base:   dabff11003f9aaf293bd8f907a62f3366bd5e65f
patch link:    https://lore.kernel.org/r/e3806f53c351c03725ecb12fb7ad100786df04f6.1770046529.git.bcodding%40hammerspace.com
patch subject: [PATCH v3 1/3] NFSD: Add a key for signing filehandles
config: x86_64-buildonly-randconfig-003-20260203 (https://download.01.org/0day-ci/archive/20260203/202602030619.d8NUY35L-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
rustc: rustc 1.88.0 (6b00bc388 2025-06-23)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260203/202602030619.d8NUY35L-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202602030619.d8NUY35L-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> fs/nfsd/nfsctl.c:1588:6: warning: variable 'fh_key' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
    1588 |         if (!nn->fh_key) {
         |             ^~~~~~~~~~~
   fs/nfsd/nfsctl.c:1594:9: note: uninitialized use occurs here
    1594 |         memcpy(fh_key, nla_data(attr), sizeof(siphash_key_t));
         |                ^~~~~~
   fs/nfsd/nfsctl.c:1588:2: note: remove the 'if' if its condition is always true
    1588 |         if (!nn->fh_key) {
         |         ^~~~~~~~~~~~~~~~
   fs/nfsd/nfsctl.c:1583:23: note: initialize the variable 'fh_key' to silence this warning
    1583 |         siphash_key_t *fh_key;
         |                              ^
         |                               = NULL
   1 warning generated.


vim +1588 fs/nfsd/nfsctl.c

  1573	
  1574	/**
  1575	 * nfsd_nl_fh_key_set - helper to copy fh_key from userspace
  1576	 * @attr: nlattr NFSD_A_SERVER_FH_KEY
  1577	 * @nn: nfsd_net
  1578	 *
  1579	 * Callers should hold nfsd_mutex, returns 0 on success or negative errno.
  1580	 */
  1581	static int nfsd_nl_fh_key_set(const struct nlattr *attr, struct nfsd_net *nn)
  1582	{
  1583		siphash_key_t *fh_key;
  1584	
  1585		if (nla_len(attr) != sizeof(siphash_key_t))
  1586			return -EINVAL;
  1587	
> 1588		if (!nn->fh_key) {
  1589			fh_key = kmalloc(sizeof(siphash_key_t), GFP_KERNEL);
  1590			if (!fh_key)
  1591				return -ENOMEM;
  1592		}
  1593	
  1594		memcpy(fh_key, nla_data(attr), sizeof(siphash_key_t));
  1595		nn->fh_key = fh_key;
  1596		return 0;
  1597	}
  1598	

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