linux-kernel - [tip:locking/futex 2/6] kernel/futex/core.c:1748:2-8: WARNING: NULL check before some freeing functions is not needed.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <202507172340.xrO8KXQq-lkp@intel.com>
Date: Thu, 17 Jul 2025 23:49:27 +0800
From: kernel test robot <lkp@...el.com>
To: Peter Zijlstra <peterz@...radead.org>
Cc: oe-kbuild-all@...ts.linux.dev, linux-kernel@...r.kernel.org,
	x86@...nel.org, Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Subject: [tip:locking/futex 2/6] kernel/futex/core.c:1748:2-8: WARNING: NULL
 check before some freeing functions is not needed.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git locking/futex
head:   7497e947bc1d3f761b46c2105c8ae37af98add54
commit: 56180dd20c19e5b0fa34822997a9ac66b517e7b3 [2/6] futex: Use RCU-based per-CPU reference counting instead of rcuref_t
config: microblaze-randconfig-r052-20250717 (https://download.01.org/0day-ci/archive/20250717/202507172340.xrO8KXQq-lkp@intel.com/config)
compiler: microblaze-linux-gcc (GCC) 11.5.0

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@...el.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202507172340.xrO8KXQq-lkp@intel.com/

cocci warnings: (new ones prefixed by >>)
>> kernel/futex/core.c:1748:2-8: WARNING: NULL check before some freeing functions is not needed.

vim +1748 kernel/futex/core.c

56180dd20c19e5 Peter Zijlstra            2025-07-10  1739  
80367ad01d93ac Sebastian Andrzej Siewior 2025-04-16  1740  void futex_hash_free(struct mm_struct *mm)
80367ad01d93ac Sebastian Andrzej Siewior 2025-04-16  1741  {
bd54df5ea7cada Sebastian Andrzej Siewior 2025-04-16  1742  	struct futex_private_hash *fph;
bd54df5ea7cada Sebastian Andrzej Siewior 2025-04-16  1743  
56180dd20c19e5 Peter Zijlstra            2025-07-10  1744  	free_percpu(mm->futex_ref);
bd54df5ea7cada Sebastian Andrzej Siewior 2025-04-16  1745  	kvfree(mm->futex_phash_new);
bd54df5ea7cada Sebastian Andrzej Siewior 2025-04-16  1746  	fph = rcu_dereference_raw(mm->futex_phash);
56180dd20c19e5 Peter Zijlstra            2025-07-10  1747  	if (fph)
bd54df5ea7cada Sebastian Andrzej Siewior 2025-04-16 @1748  		kvfree(fph);
bd54df5ea7cada Sebastian Andrzej Siewior 2025-04-16  1749  }
bd54df5ea7cada Sebastian Andrzej Siewior 2025-04-16  1750  

:::::: The code at line 1748 was first introduced by commit
:::::: bd54df5ea7cadac520e346d5f0fe5d58e635b6ba futex: Allow to resize the private local hash

:::::: TO: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
:::::: CC: Peter Zijlstra <peterz@...radead.org>

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki