From: kernel test robot <lkp@intel.com>
To: Lorenzo Bianconi <lorenzo@kernel.org>,
bpf@vger.kernel.org, netdev@vger.kernel.org
Cc: kbuild-all@lists.01.org, clang-built-linux@googlegroups.com,
lorenzo.bianconi@redhat.com, davem@davemloft.net,
kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net,
shayagr@amazon.com, john.fastabend@gmail.com, dsahern@kernel.org
Subject: Re: [PATCH v7 bpf-next 09/14] bpd: add multi-buffer support to xdp copy helpers
Date: Sat, 20 Mar 2021 08:51:23 +0800 [thread overview]
Message-ID: <202103200854.hVTC06V7-lkp@intel.com> (raw)
In-Reply-To: <d7e913be6855a2aeaaff16de39960b38afd06da7.1616179034.git.lorenzo@kernel.org>
[-- Attachment #1: Type: text/plain, Size: 4008 bytes --]
Hi Lorenzo,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on bpf-next/master]
url: https://github.com/0day-ci/linux/commits/Lorenzo-Bianconi/mvneta-introduce-XDP-multi-buffer-support/20210320-055103
base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
config: arm-randconfig-r023-20210318 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 436c6c9c20cc522c92a923440a5fc509c342a7db)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install arm cross compiling tool for clang build
# apt-get install binutils-arm-linux-gnueabi
# https://github.com/0day-ci/linux/commit/9603affe766576f892f3a8e02d58dbe83092c74a
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Lorenzo-Bianconi/mvneta-introduce-XDP-multi-buffer-support/20210320-055103
git checkout 9603affe766576f892f3a8e02d58dbe83092c74a
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All warnings (new ones prefixed by >>):
>> net/core/filter.c:4579:16: warning: variable 'copy_len' is used uninitialized whenever 'for' loop exits because its condition is false [-Wsometimes-uninitialized]
for (i = 0; i < xdp_sinfo->nr_frags; i++) {
^~~~~~~~~~~~~~~~~~~~~~~
net/core/filter.c:4593:30: note: uninitialized use occurs here
memcpy(dst_buff, src_buff, copy_len);
^~~~~~~~
net/core/filter.c:4579:16: note: remove the condition if it is always true
for (i = 0; i < xdp_sinfo->nr_frags; i++) {
^~~~~~~~~~~~~~~~~~~~~~~
net/core/filter.c:4570:25: note: initialize the variable 'copy_len' to silence this warning
unsigned long copy_len;
^
= 0
1 warning generated.
vim +4579 net/core/filter.c
4551
4552 static unsigned long bpf_xdp_copy(void *dst_buff, const void *ctx,
4553 unsigned long off, unsigned long len)
4554 {
4555 struct xdp_buff *xdp = (struct xdp_buff *)ctx;
4556 struct xdp_shared_info *xdp_sinfo;
4557 unsigned long base_len;
4558 const void *src_buff;
4559
4560 if (likely(!xdp->mb)) {
4561 src_buff = xdp->data;
4562 memcpy(dst_buff, src_buff + off, len);
4563
4564 return 0;
4565 }
4566
4567 base_len = xdp->data_end - xdp->data;
4568 xdp_sinfo = xdp_get_shared_info_from_buff(xdp);
4569 do {
4570 unsigned long copy_len;
4571
4572 if (off < base_len) {
4573 src_buff = xdp->data + off;
4574 copy_len = min(len, base_len - off);
4575 } else {
4576 unsigned long frag_off_total = base_len;
4577 int i;
4578
> 4579 for (i = 0; i < xdp_sinfo->nr_frags; i++) {
4580 skb_frag_t *frag = &xdp_sinfo->frags[i];
4581 unsigned long frag_len = xdp_get_frag_size(frag);
4582 unsigned long frag_off = off - frag_off_total;
4583
4584 if (frag_off < frag_len) {
4585 src_buff = xdp_get_frag_address(frag) +
4586 frag_off;
4587 copy_len = min(len, frag_len - frag_off);
4588 break;
4589 }
4590 frag_off_total += frag_len;
4591 }
4592 }
4593 memcpy(dst_buff, src_buff, copy_len);
4594 off += copy_len;
4595 len -= copy_len;
4596 dst_buff += copy_len;
4597 } while (len);
4598
4599 return 0;
4600 }
4601
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
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next prev parent reply other threads:[~2021-03-20 0:52 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-19 21:47 [PATCH v7 bpf-next 00/14] mvneta: introduce XDP multi-buffer support Lorenzo Bianconi
2021-03-19 21:47 ` [PATCH v7 bpf-next 01/14] xdp: introduce mb in xdp_buff/xdp_frame Lorenzo Bianconi
2021-03-19 21:47 ` [PATCH v7 bpf-next 02/14] xdp: add xdp_shared_info data structure Lorenzo Bianconi
2021-03-19 21:47 ` [PATCH v7 bpf-next 03/14] net: mvneta: update mb bit before passing the xdp buffer to eBPF layer Lorenzo Bianconi
2021-03-19 21:47 ` [PATCH v7 bpf-next 04/14] xdp: add multi-buff support to xdp_return_{buff/frame} Lorenzo Bianconi
2021-03-19 21:47 ` [PATCH v7 bpf-next 05/14] net: mvneta: add multi buffer support to XDP_TX Lorenzo Bianconi
2021-03-19 21:47 ` [PATCH v7 bpf-next 06/14] net: mvneta: enable jumbo frames for XDP Lorenzo Bianconi
2021-03-19 21:47 ` [PATCH v7 bpf-next 07/14] net: xdp: add multi-buff support to xdp_build_skb_from_fram Lorenzo Bianconi
2021-03-19 21:47 ` [PATCH v7 bpf-next 08/14] bpf: add multi-buff support to the bpf_xdp_adjust_tail() API Lorenzo Bianconi
2021-03-19 21:47 ` [PATCH v7 bpf-next 09/14] bpd: add multi-buffer support to xdp copy helpers Lorenzo Bianconi
2021-03-20 0:51 ` kernel test robot [this message]
2021-03-20 3:47 ` kernel test robot
2021-03-19 21:47 ` [PATCH v7 bpf-next 10/14] bpf: add new frame_length field to the XDP ctx Lorenzo Bianconi
2021-03-20 3:42 ` David Ahern
2021-03-22 9:29 ` Eelco Chaudron
2021-03-22 15:05 ` David Ahern
2021-03-19 21:47 ` [PATCH v7 bpf-next 11/14] bpf: move user_size out of bpf_test_init Lorenzo Bianconi
2021-03-19 21:47 ` [PATCH v7 bpf-next 12/14] bpf: introduce multibuff support to bpf_prog_test_run_xdp() Lorenzo Bianconi
2021-03-19 21:47 ` [PATCH v7 bpf-next 13/14] bpf: test_run: add xdp_shared_info pointer in bpf_test_finish signature Lorenzo Bianconi
2021-03-19 21:47 ` [PATCH v7 bpf-next 14/14] bpf: update xdp_adjust_tail selftest to include multi-buffer Lorenzo Bianconi
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