arch/x86/kernel/kvmclock.c:269 kvmclock_setup_percpu() error: testing array offset 'cpu' after use.

arch/x86/kernel/kvmclock.c:269 kvmclock_setup_percpu() error: testing array offset 'cpu' after use.

[kernel test robot]

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
CC: linux-kernel@vger.kernel.org
TO: Thomas Gleixner <tglx@linutronix.de>
CC: Pavel Tatashin <pasha.tatashin@oracle.com>

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   33cc938e65a98f1d29d0a18403dbbee050dcad9a
commit: 95a3d4454bb1cf5bfd666c27fdd2dc188e17c14d x86/kvmclock: Switch kvmclock data to a PER_CPU variable
date:   5 years ago
:::::: branch date: 5 hours ago
:::::: commit date: 5 years ago
config: x86_64-randconfig-x006-20230817 (https://download.01.org/0day-ci/archive/20231203/202312032306.PrSrLRqa-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce: (https://download.01.org/0day-ci/archive/20231203/202312032306.PrSrLRqa-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>
| Reported-by: Dan Carpenter <error27@gmail.com>
| Closes: https://lore.kernel.org/r/202312032306.PrSrLRqa-lkp@intel.com/

smatch warnings:
arch/x86/kernel/kvmclock.c:269 kvmclock_setup_percpu() error: testing array offset 'cpu' after use.

vim +/cpu +269 arch/x86/kernel/kvmclock.c

e499a9b6dc488a Thomas Gleixner 2018-07-19  255  
95a3d4454bb1cf Thomas Gleixner 2018-07-19  256  static int kvmclock_setup_percpu(unsigned int cpu)
95a3d4454bb1cf Thomas Gleixner 2018-07-19  257  {
95a3d4454bb1cf Thomas Gleixner 2018-07-19  258  	struct pvclock_vsyscall_time_info *p = per_cpu(hv_clock_per_cpu, cpu);
95a3d4454bb1cf Thomas Gleixner 2018-07-19  259  
95a3d4454bb1cf Thomas Gleixner 2018-07-19  260  	/*
95a3d4454bb1cf Thomas Gleixner 2018-07-19  261  	 * The per cpu area setup replicates CPU0 data to all cpu
95a3d4454bb1cf Thomas Gleixner 2018-07-19  262  	 * pointers. So carefully check. CPU0 has been set up in init
95a3d4454bb1cf Thomas Gleixner 2018-07-19  263  	 * already.
95a3d4454bb1cf Thomas Gleixner 2018-07-19  264  	 */
95a3d4454bb1cf Thomas Gleixner 2018-07-19  265  	if (!cpu || (p && p != per_cpu(hv_clock_per_cpu, 0)))
95a3d4454bb1cf Thomas Gleixner 2018-07-19  266  		return 0;
95a3d4454bb1cf Thomas Gleixner 2018-07-19  267  
95a3d4454bb1cf Thomas Gleixner 2018-07-19  268  	/* Use the static page for the first CPUs, allocate otherwise */
95a3d4454bb1cf Thomas Gleixner 2018-07-19 @269  	if (cpu < HVC_BOOT_ARRAY_SIZE)
95a3d4454bb1cf Thomas Gleixner 2018-07-19  270  		p = &hv_clock_boot[cpu];
95a3d4454bb1cf Thomas Gleixner 2018-07-19  271  	else
95a3d4454bb1cf Thomas Gleixner 2018-07-19  272  		p = kzalloc(sizeof(*p), GFP_KERNEL);
95a3d4454bb1cf Thomas Gleixner 2018-07-19  273  
95a3d4454bb1cf Thomas Gleixner 2018-07-19  274  	per_cpu(hv_clock_per_cpu, cpu) = p;
95a3d4454bb1cf Thomas Gleixner 2018-07-19  275  	return p ? 0 : -ENOMEM;
95a3d4454bb1cf Thomas Gleixner 2018-07-19  276  }
95a3d4454bb1cf Thomas Gleixner 2018-07-19  277  

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