Re: [PATCH RFC] bpf, x64: allow not-converged images when BPF_JIT_ALWAYS_ON is set

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

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Hi Gary,

[FYI, it's a private test report for your RFC patch.]
[auto build test WARNING on bpf-next/master]
[also build test WARNING on bpf/master ipvs/master v5.10-rc3 next-20201112]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Gary-Lin/bpf-x64-allow-not-converged-images-when-BPF_JIT_ALWAYS_ON-is-set/20201113-164003
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
config: x86_64-randconfig-a002-20201113 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 9e0c35655b6e8186baef8840b26ba4090503b554)
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 x86_64 cross compiling tool for clang build
        # apt-get install binutils-x86-64-linux-gnu
        # https://github.com/0day-ci/linux/commit/e491680a9f8f3835010cbcaa58d38382ae94d1e5
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Gary-Lin/bpf-x64-allow-not-converged-images-when-BPF_JIT_ALWAYS_ON-is-set/20201113-164003
        git checkout e491680a9f8f3835010cbcaa58d38382ae94d1e5
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 

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 >>):

   arch/x86/net/bpf_jit_comp.c:1959:5: warning: no previous prototype for function 'arch_prepare_bpf_dispatcher' [-Wmissing-prototypes]
   int arch_prepare_bpf_dispatcher(void *image, s64 *funcs, int num_funcs)
       ^
   arch/x86/net/bpf_jit_comp.c:1959:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int arch_prepare_bpf_dispatcher(void *image, s64 *funcs, int num_funcs)
   ^
   static 
>> arch/x86/net/bpf_jit_comp.c:2050:1: warning: unused label 'out_image' [-Wunused-label]
   out_image:
   ^~~~~~~~~~
   2 warnings generated.

vim +/out_image +2050 arch/x86/net/bpf_jit_comp.c

e491680a9f8f38 Gary Lin           2020-11-13  1976  
d1c55ab5e41fcd Daniel Borkmann    2016-05-13  1977  struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
f3c2af7ba17a83 Alexei Starovoitov 2014-05-13  1978  {
f3c2af7ba17a83 Alexei Starovoitov 2014-05-13  1979  	struct bpf_binary_header *header = NULL;
959a7579160349 Daniel Borkmann    2016-05-13  1980  	struct bpf_prog *tmp, *orig_prog = prog;
1c2a088a6626d4 Alexei Starovoitov 2017-12-14  1981  	struct x64_jit_data *jit_data;
f3c2af7ba17a83 Alexei Starovoitov 2014-05-13  1982  	int proglen, oldproglen = 0;
f3c2af7ba17a83 Alexei Starovoitov 2014-05-13  1983  	struct jit_context ctx = {};
959a7579160349 Daniel Borkmann    2016-05-13  1984  	bool tmp_blinded = false;
1c2a088a6626d4 Alexei Starovoitov 2017-12-14  1985  	bool extra_pass = false;
f3c2af7ba17a83 Alexei Starovoitov 2014-05-13  1986  	u8 *image = NULL;
f3c2af7ba17a83 Alexei Starovoitov 2014-05-13  1987  	int *addrs;
f3c2af7ba17a83 Alexei Starovoitov 2014-05-13  1988  	int pass;
f3c2af7ba17a83 Alexei Starovoitov 2014-05-13  1989  	int i;
f3c2af7ba17a83 Alexei Starovoitov 2014-05-13  1990  
60b58afc96c9df Alexei Starovoitov 2017-12-14  1991  	if (!prog->jit_requested)
959a7579160349 Daniel Borkmann    2016-05-13  1992  		return orig_prog;
959a7579160349 Daniel Borkmann    2016-05-13  1993  
959a7579160349 Daniel Borkmann    2016-05-13  1994  	tmp = bpf_jit_blind_constants(prog);
a2c7a98301d9f9 Ingo Molnar        2018-04-27  1995  	/*
a2c7a98301d9f9 Ingo Molnar        2018-04-27  1996  	 * If blinding was requested and we failed during blinding,
959a7579160349 Daniel Borkmann    2016-05-13  1997  	 * we must fall back to the interpreter.
959a7579160349 Daniel Borkmann    2016-05-13  1998  	 */
959a7579160349 Daniel Borkmann    2016-05-13  1999  	if (IS_ERR(tmp))
959a7579160349 Daniel Borkmann    2016-05-13  2000  		return orig_prog;
959a7579160349 Daniel Borkmann    2016-05-13  2001  	if (tmp != prog) {
959a7579160349 Daniel Borkmann    2016-05-13  2002  		tmp_blinded = true;
959a7579160349 Daniel Borkmann    2016-05-13  2003  		prog = tmp;
959a7579160349 Daniel Borkmann    2016-05-13  2004  	}
f3c2af7ba17a83 Alexei Starovoitov 2014-05-13  2005  
1c2a088a6626d4 Alexei Starovoitov 2017-12-14  2006  	jit_data = prog->aux->jit_data;
1c2a088a6626d4 Alexei Starovoitov 2017-12-14  2007  	if (!jit_data) {
1c2a088a6626d4 Alexei Starovoitov 2017-12-14  2008  		jit_data = kzalloc(sizeof(*jit_data), GFP_KERNEL);
1c2a088a6626d4 Alexei Starovoitov 2017-12-14  2009  		if (!jit_data) {
1c2a088a6626d4 Alexei Starovoitov 2017-12-14  2010  			prog = orig_prog;
1c2a088a6626d4 Alexei Starovoitov 2017-12-14  2011  			goto out;
1c2a088a6626d4 Alexei Starovoitov 2017-12-14  2012  		}
1c2a088a6626d4 Alexei Starovoitov 2017-12-14  2013  		prog->aux->jit_data = jit_data;
1c2a088a6626d4 Alexei Starovoitov 2017-12-14  2014  	}
1c2a088a6626d4 Alexei Starovoitov 2017-12-14  2015  	addrs = jit_data->addrs;
1c2a088a6626d4 Alexei Starovoitov 2017-12-14  2016  	if (addrs) {
1c2a088a6626d4 Alexei Starovoitov 2017-12-14  2017  		ctx = jit_data->ctx;
1c2a088a6626d4 Alexei Starovoitov 2017-12-14  2018  		oldproglen = jit_data->proglen;
1c2a088a6626d4 Alexei Starovoitov 2017-12-14  2019  		image = jit_data->image;
1c2a088a6626d4 Alexei Starovoitov 2017-12-14  2020  		header = jit_data->header;
1c2a088a6626d4 Alexei Starovoitov 2017-12-14  2021  		extra_pass = true;
1c2a088a6626d4 Alexei Starovoitov 2017-12-14  2022  		goto skip_init_addrs;
1c2a088a6626d4 Alexei Starovoitov 2017-12-14  2023  	}
7c2e988f400e83 Alexei Starovoitov 2019-07-30  2024  	addrs = kmalloc_array(prog->len + 1, sizeof(*addrs), GFP_KERNEL);
959a7579160349 Daniel Borkmann    2016-05-13  2025  	if (!addrs) {
959a7579160349 Daniel Borkmann    2016-05-13  2026  		prog = orig_prog;
1c2a088a6626d4 Alexei Starovoitov 2017-12-14  2027  		goto out_addrs;
959a7579160349 Daniel Borkmann    2016-05-13  2028  	}
f3c2af7ba17a83 Alexei Starovoitov 2014-05-13  2029  
a2c7a98301d9f9 Ingo Molnar        2018-04-27  2030  	/*
a2c7a98301d9f9 Ingo Molnar        2018-04-27  2031  	 * Before first pass, make a rough estimation of addrs[]
a2c7a98301d9f9 Ingo Molnar        2018-04-27  2032  	 * each BPF instruction is translated to less than 64 bytes
f3c2af7ba17a83 Alexei Starovoitov 2014-05-13  2033  	 */
7c2e988f400e83 Alexei Starovoitov 2019-07-30  2034  	for (proglen = 0, i = 0; i <= prog->len; i++) {
f3c2af7ba17a83 Alexei Starovoitov 2014-05-13  2035  		proglen += 64;
f3c2af7ba17a83 Alexei Starovoitov 2014-05-13  2036  		addrs[i] = proglen;
f3c2af7ba17a83 Alexei Starovoitov 2014-05-13  2037  	}
f3c2af7ba17a83 Alexei Starovoitov 2014-05-13  2038  	ctx.cleanup_addr = proglen;
1c2a088a6626d4 Alexei Starovoitov 2017-12-14  2039  skip_init_addrs:
f3c2af7ba17a83 Alexei Starovoitov 2014-05-13  2040  
a2c7a98301d9f9 Ingo Molnar        2018-04-27  2041  	/*
a2c7a98301d9f9 Ingo Molnar        2018-04-27  2042  	 * JITed image shrinks with every pass and the loop iterates
a2c7a98301d9f9 Ingo Molnar        2018-04-27  2043  	 * until the image stops shrinking. Very large BPF programs
3f7352bf21f8fd Alexei Starovoitov 2015-05-22  2044  	 * may converge on the last pass. In such case do one more
a2c7a98301d9f9 Ingo Molnar        2018-04-27  2045  	 * pass to emit the final image.
3f7352bf21f8fd Alexei Starovoitov 2015-05-22  2046  	 */
e491680a9f8f38 Gary Lin           2020-11-13  2047  	for (pass = 0; pass < MAX_JIT_PASSES || image; pass++) {
f3c2af7ba17a83 Alexei Starovoitov 2014-05-13  2048  		proglen = do_jit(prog, addrs, image, oldproglen, &ctx);
f3c2af7ba17a83 Alexei Starovoitov 2014-05-13  2049  		if (proglen <= 0) {
3aab8884c9eb99 Daniel Borkmann    2018-05-02 @2050  out_image:

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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