[bpf-next:master 72/83] kernel/bpf/liveness.c:309:34: warning: variable 'cnt' set but not used

[bpf-next:master 72/83] kernel/bpf/liveness.c:309:34: warning: variable 'cnt' set but not used

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
head:   d6bae125f21f74201a3eab0996b2f27be3abc4bf
commit: 2c167d91775b0928eba1d2b9b5483ede63ca7b2e [72/83] bpf: change logging scheme for live stack analysis
config: hexagon-allmodconfig (https://download.01.org/0day-ci/archive/20260411/202604111401.eqzyF2kx-lkp@intel.com/config)
compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260411/202604111401.eqzyF2kx-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/202604111401.eqzyF2kx-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> kernel/bpf/liveness.c:309:34: warning: variable 'cnt' set but not used [-Wunused-but-set-variable]
     309 |         u32 i, frame, po_start, po_end, cnt;
         |                                         ^
   1 warning generated.


vim +/cnt +309 kernel/bpf/liveness.c

b3698c356ad92b Eduard Zingerman 2025-09-18  305  
6762e3a0bce5fc Eduard Zingerman 2026-04-10  306  /* Fixed-point computation of @live_before marks */
6762e3a0bce5fc Eduard Zingerman 2026-04-10  307  static void update_instance(struct bpf_verifier_env *env, struct func_instance *instance)
b3698c356ad92b Eduard Zingerman 2025-09-18  308  {
6762e3a0bce5fc Eduard Zingerman 2026-04-10 @309  	u32 i, frame, po_start, po_end, cnt;
b3698c356ad92b Eduard Zingerman 2025-09-18  310  	int *insn_postorder = env->cfg.insn_postorder;
b3698c356ad92b Eduard Zingerman 2025-09-18  311  	struct bpf_subprog_info *subprog;
b3698c356ad92b Eduard Zingerman 2025-09-18  312  	bool changed;
8d3219f64d98f4 Eduard Zingerman 2026-04-10  313  
6762e3a0bce5fc Eduard Zingerman 2026-04-10  314  	instance->must_write_initialized = true;
6762e3a0bce5fc Eduard Zingerman 2026-04-10  315  	subprog = &env->subprog_info[instance->subprog];
b3698c356ad92b Eduard Zingerman 2025-09-18  316  	po_start = subprog->postorder_start;
b3698c356ad92b Eduard Zingerman 2025-09-18  317  	po_end = (subprog + 1)->postorder_start;
b3698c356ad92b Eduard Zingerman 2025-09-18  318  	cnt = 0;
b3698c356ad92b Eduard Zingerman 2025-09-18  319  	/* repeat until fixed point is reached */
b3698c356ad92b Eduard Zingerman 2025-09-18  320  	do {
b3698c356ad92b Eduard Zingerman 2025-09-18  321  		cnt++;
b3698c356ad92b Eduard Zingerman 2025-09-18  322  		changed = false;
6762e3a0bce5fc Eduard Zingerman 2026-04-10  323  		for (frame = 0; frame <= instance->depth; frame++) {
b3698c356ad92b Eduard Zingerman 2025-09-18  324  			if (!instance->frames[frame])
b3698c356ad92b Eduard Zingerman 2025-09-18  325  				continue;
b3698c356ad92b Eduard Zingerman 2025-09-18  326  
b3698c356ad92b Eduard Zingerman 2025-09-18  327  			for (i = po_start; i < po_end; i++)
b3698c356ad92b Eduard Zingerman 2025-09-18  328  				changed |= update_insn(env, instance, frame, insn_postorder[i]);
b3698c356ad92b Eduard Zingerman 2025-09-18  329  		}
b3698c356ad92b Eduard Zingerman 2025-09-18  330  	} while (changed);
b3698c356ad92b Eduard Zingerman 2025-09-18  331  }
b3698c356ad92b Eduard Zingerman 2025-09-18  332  

:::::: The code at line 309 was first introduced by commit
:::::: 6762e3a0bce5fce94bca3c34ff13cde6a07b87f3 bpf: simplify liveness to use (callsite, depth) keyed func_instances

:::::: TO: Eduard Zingerman <eddyz87@gmail.com>
:::::: CC: Alexei Starovoitov <ast@kernel.org>

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