[toke:xdp-queueing-03 7/9] net/core/filter.c:9720:14: warning: assignment to 'struct btf *' from 'int' makes pointer from integer without a cast

From: kernel test robot
Date: Sun Mar 13 2022 - 18:46:31 EST


tree: https://git.kernel.org/pub/scm/linux/kernel/git/toke/linux.git xdp-queueing-03
head: 3e7f25d58b1bfd5ad623678bf9e11f27c98a8094
commit: 28d9ca982b9ae96bcad2bee81647ba18ae049a69 [7/9] bpf: Enable direct packet access for dequeue packets
config: um-i386_defconfig (https://download.01.org/0day-ci/archive/20220314/202203140612.pwI8TzBG-lkp@xxxxxxxxx/config)
compiler: gcc-9 (Ubuntu 9.4.0-1ubuntu1~20.04) 9.4.0
reproduce (this is a W=1 build):
# https://git.kernel.org/pub/scm/linux/kernel/git/toke/linux.git/commit/?id=28d9ca982b9ae96bcad2bee81647ba18ae049a69
git remote add toke https://git.kernel.org/pub/scm/linux/kernel/git/toke/linux.git
git fetch --no-tags toke xdp-queueing-03
git checkout 28d9ca982b9ae96bcad2bee81647ba18ae049a69
# save the config file to linux build tree
mkdir build_dir
make W=1 O=build_dir ARCH=um SUBARCH=i386 SHELL=/bin/bash net/core/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

In file included from include/linux/skmsg.h:7,
from net/core/filter.c:38:
include/linux/bpf.h:2062:15: error: return type defaults to 'int' [-Werror=return-type]
2062 | static inline bpf_get_btf_vmlinux(void)
| ^~~~~~~~~~~~~~~~~~~
include/linux/bpf.h: In function 'bpf_get_btf_vmlinux':
include/linux/bpf.h:2064:9: warning: returning 'void *' from a function with return type 'int' makes integer from pointer without a cast [-Wint-conversion]
2064 | return ERR_PTR(-EINVAL);
| ^~~~~~~~~~~~~~~~
net/core/filter.c: In function 'dequeue_btf_struct_access':
>> net/core/filter.c:9720:14: warning: assignment to 'struct btf *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
9720 | btf_vmlinux = bpf_get_btf_vmlinux();
| ^
net/core/filter.c: In function 'dequeue_get_convert_ctx_access':
net/core/filter.c:9848:14: warning: assignment to 'struct btf *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
9848 | btf_vmlinux = bpf_get_btf_vmlinux();
| ^
cc1: some warnings being treated as errors


vim +9720 net/core/filter.c

9709
9710 static int dequeue_btf_struct_access(struct bpf_verifier_log *log,
9711 const struct btf *btf,
9712 const struct btf_type *t, int off, int size,
9713 enum bpf_access_type atype,
9714 u32 *next_btf_id, enum bpf_type_flag *flag)
9715 {
9716 const struct btf_type *pkt_type;
9717 enum bpf_reg_type reg_type;
9718 struct btf *btf_vmlinux;
9719
> 9720 btf_vmlinux = bpf_get_btf_vmlinux();
9721 if (IS_ERR(btf_vmlinux) || btf != btf_vmlinux)
9722 return -EINVAL;
9723
9724 if (atype != BPF_READ) {
9725 bpf_log(log, "only read is supported\n");
9726 return -EACCES;
9727 }
9728
9729 pkt_type = btf_type_by_id(btf_vmlinux, xdp_md_btf_ids[0]);
9730 if (!pkt_type)
9731 return -EINVAL;
9732 if (t != pkt_type)
9733 return btf_struct_access(log, btf, t, off, size, atype,
9734 next_btf_id, flag);
9735
9736 switch (off) {
9737 case offsetof(struct xdp_md, data):
9738 reg_type = PTR_TO_PACKET;
9739 break;
9740 case offsetof(struct xdp_md, data_meta):
9741 reg_type = PTR_TO_PACKET_META;
9742 break;
9743 case offsetof(struct xdp_md, data_end):
9744 reg_type = PTR_TO_PACKET_END;
9745 break;
9746 default:
9747 bpf_log(log, "only access to data, data_meta, and data_end allowed for xdp_md\n");
9748 return -EACCES;
9749 }
9750
9751 if (!__is_valid_xdp_access(off, size)) {
9752 bpf_log(log, "invalid xdp_md access off=%d size=%d\n", off, size);
9753 return -EINVAL;
9754 }
9755 return reg_type;
9756 }
9757

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