Re: [RFC PATCH bpf-next] bpf: Support shadow stack for bpf progs

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

Hi Yonghong,

[This is a private test report for your RFC patch.]
kernel test robot noticed the following build warnings:

[auto build test WARNING on bpf-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Yonghong-Song/bpf-Support-shadow-stack-for-bpf-progs/20240610-132108
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20240610051839.1296086-1-yonghong.song%40linux.dev
patch subject: [RFC PATCH bpf-next] bpf: Support shadow stack for bpf progs
config: x86_64-randconfig-123-20240614 (https://download.01.org/0day-ci/archive/20240614/202406141719.ilJ36VlE-lkp@intel.com/config)
compiler: clang version 18.1.5 (https://github.com/llvm/llvm-project 617a15a9eac96088ae5e9134248d8236e34b91b1)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240614/202406141719.ilJ36VlE-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/202406141719.ilJ36VlE-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> kernel/bpf/syscall.c:2247:30: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected void [noderef] __percpu *__pdata @@     got void *percpu_shadow_stack_ptr @@
   kernel/bpf/syscall.c:2247:30: sparse:     expected void [noderef] __percpu *__pdata
   kernel/bpf/syscall.c:2247:30: sparse:     got void *percpu_shadow_stack_ptr

vim +2247 kernel/bpf/syscall.c

  2240	
  2241	static void __bpf_prog_put_rcu(struct rcu_head *rcu)
  2242	{
  2243		struct bpf_prog_aux *aux = container_of(rcu, struct bpf_prog_aux, rcu);
  2244	
  2245		kvfree(aux->func_info);
  2246		kfree(aux->func_info_aux);
> 2247		free_percpu(aux->prog->percpu_shadow_stack_ptr);
  2248		free_uid(aux->user);
  2249		security_bpf_prog_free(aux->prog);
  2250		bpf_prog_free(aux->prog);
  2251	}
  2252	

-- 
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https://github.com/intel/lkp-tests/wiki