Re: [RFC bpf-next v2 5/6] bpf: Add a new dynptr type for CGRUP_SOCKOPT.

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

Hi,

[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/thinker-li-gmail-com/bpf-enable-sleepable-BPF-programs-attached-to-cgroup-get-set-sockopt/20230811-123333
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20230811043127.1318152-6-thinker.li%40gmail.com
patch subject: [RFC bpf-next v2 5/6] bpf: Add a new dynptr type for CGRUP_SOCKOPT.
config: x86_64-randconfig-r081-20230814 (https://download.01.org/0day-ci/archive/20230814/202308141248.9fi9h13X-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce: (https://download.01.org/0day-ci/archive/20230814/202308141248.9fi9h13X-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/202308141248.9fi9h13X-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
   kernel/bpf/helpers.c:684:32: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected void [noderef] __user *to @@     got void *dst__uninit @@
   kernel/bpf/helpers.c:684:32: sparse:     expected void [noderef] __user *to
   kernel/bpf/helpers.c:684:32: sparse:     got void *dst__uninit
>> kernel/bpf/helpers.c:2588:55: sparse: sparse: incorrect type in argument 2 (different address spaces) @@     expected void const [noderef] __user *from @@     got unsigned char [usertype] *optval @@
   kernel/bpf/helpers.c:2588:55: sparse:     expected void const [noderef] __user *from
   kernel/bpf/helpers.c:2588:55: sparse:     got unsigned char [usertype] *optval
>> kernel/bpf/helpers.c:2619:45: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected void [noderef] __user *to @@     got unsigned char [usertype] *optval @@
   kernel/bpf/helpers.c:2619:45: sparse:     expected void [noderef] __user *to
   kernel/bpf/helpers.c:2619:45: sparse:     got unsigned char [usertype] *optval
   kernel/bpf/helpers.c:2446:18: sparse: sparse: context imbalance in 'bpf_rcu_read_lock' - wrong count at exit
   kernel/bpf/helpers.c: note: in included file (through include/linux/workqueue.h, include/linux/bpf.h):
   include/linux/rcupdate.h:780:9: sparse: sparse: context imbalance in 'bpf_rcu_read_unlock' - unexpected unlock

vim +2588 kernel/bpf/helpers.c

  2548	
  2549	/* Initialize a sockopt dynptr from a user or installed optval pointer.
  2550	 *
  2551	 * sopt->optval can be a user pointer or a kernel pointer. A kernel pointer
  2552	 * can be a buffer allocated by the caller of the BPF program or a buffer
  2553	 * installed by other BPF programs through bpf_so_optval_install().
  2554	 *
  2555	 * Atmost one dynptr shall be created by this function at any moment, or
  2556	 * it will return -EINVAL. You can create another dypptr by this function
  2557	 * after release the previous one by bpf_so_optval_release().
  2558	 *
  2559	 * A dynptr that is initialized when optval is a user pointer is an
  2560	 * exception. In this case, the dynptr will point to a kernel buffer with
  2561	 * the same content as the user buffer. To simplify the code, users should
  2562	 * always make sure having only one dynptr initialized by this function at
  2563	 * any moment.
  2564	 */
  2565	__bpf_kfunc int bpf_so_optval_from(struct bpf_sockopt *sopt,
  2566					   struct bpf_dynptr_kern *ptr__uninit,
  2567					   unsigned int size)
  2568	{
  2569		struct bpf_sockopt_kern *sopt_kern = (struct bpf_sockopt_kern *)sopt;
  2570		int err;
  2571	
  2572		bpf_dynptr_set_null(ptr__uninit);
  2573	
  2574		if (size > (sopt_kern->optval_end - sopt_kern->optval))
  2575			return -EINVAL;
  2576	
  2577		if (size == 0)
  2578			size = min(sopt_kern->optlen,
  2579				   (int)(sopt_kern->optval_end - sopt_kern->optval));
  2580	
  2581		if (sopt_kern->flags & BPF_SOCKOPT_FLAG_OPTVAL_DYNPTR)
  2582			return -EINVAL;
  2583	
  2584		if (sopt_kern->flags & BPF_SOCKOPT_FLAG_OPTVAL_USER) {
  2585			err = bpf_so_optval_alloc(sopt, sopt_kern->optlen, ptr__uninit);
  2586			if (err >= 0)
  2587				err = copy_from_user(ptr__uninit->data,
> 2588						     sopt_kern->optval,
  2589						     size);
  2590			return err;
  2591		}
  2592	
  2593		bpf_dynptr_init(ptr__uninit, sopt_kern->optval,
  2594				BPF_DYNPTR_TYPE_CGROUP_SOCKOPT, 0,
  2595				size);
  2596		sopt_kern->flags |= BPF_SOCKOPT_FLAG_OPTVAL_DYNPTR;
  2597	
  2598		return size;
  2599	}
  2600	
  2601	/**
  2602	 * int bpf_so_optval_copy_to_r(struct bpf_sockopt *sopt,
  2603	 *                             void *ptr, u32 ptr__sz)
  2604	 *     Description
  2605	 *             Copy data from *ptr* to *sopt->optval*.
  2606	 *     Return
  2607	 *             >= 0 on success, or a negative error in case of failure.
  2608	 */
  2609	__bpf_kfunc int bpf_so_optval_copy_to_r(struct bpf_sockopt *sopt,
  2610						void *ptr, u32 ptr__sz)
  2611	{
  2612		struct bpf_sockopt_kern *sopt_kern = (struct bpf_sockopt_kern *)sopt;
  2613		int ret;
  2614	
  2615		if (ptr__sz > (sopt_kern->optval_end - sopt_kern->optval))
  2616			return -EINVAL;
  2617	
  2618		if (sopt_kern->flags & BPF_SOCKOPT_FLAG_OPTVAL_USER) {
> 2619			ret = copy_to_user(sopt_kern->optval, ptr,
  2620					   ptr__sz);
  2621			if (unlikely(ret))
  2622				return -EFAULT;
  2623		} else {
  2624			/* Use memmove() in case of optval & ptr overlap. */
  2625			memmove(sopt_kern->optval, ptr, ptr__sz);
  2626			ret = ptr__sz;
  2627		}
  2628	
  2629		return ret;
  2630	}
  2631	

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