On Tue, Apr 28, 2020 at 9:36 AM Yonghong Song <yhs@xxxxxx> wrote: > > > > On 4/27/20 11:02 PM, kbuild test robot wrote: > > Hi Yonghong, > > > > I love your patch! Perhaps something to improve: > > > > [auto build test WARNING on bpf-next/master] > > [cannot apply to bpf/master net/master vhost/linux-next net-next/master linus/master v5.7-rc3 next-20200424] > > [if your patch is applied to the wrong git tree, please drop us a note to help > > improve the system. BTW, we also suggest to use '--base' option to specify the > > base tree in git format-patch, please see https://urldefense.proofpoint.com/v2/url?u=https-3A__stackoverflow.com_a_37406982&d=DwIBAg&c=5VD0RTtNlTh3ycd41b3MUw&r=DA8e1B5r073vIqRrFz7MRA&m=ecuvAWhErc8x32mTscXvNhgSPkwcM7tK05lEVYIQMbI&s=rUkkN8hfXpHttD7t9NCfe5OIFTZZ_cn_SQTDjvs1cj0&e= ] > > > > url: https://github.com/0day-ci/linux/commits/Yonghong-Song/bpf-implement-bpf-iterator-for-kernel-data/20200428-115101 > > base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master > > config: sh-allmodconfig (attached as .config) > > compiler: sh4-linux-gcc (GCC) 9.3.0 > > reproduce: > > wget https://urldefense.proofpoint.com/v2/url?u=https-3A__raw.githubusercontent.com_intel_lkp-2Dtests_master_sbin_make.cross&d=DwIBAg&c=5VD0RTtNlTh3ycd41b3MUw&r=DA8e1B5r073vIqRrFz7MRA&m=ecuvAWhErc8x32mTscXvNhgSPkwcM7tK05lEVYIQMbI&s=mm3zd05JFgyD1Fvvg5yehcYq7d9KLZkN7XSYyLaJRkA&e= -O ~/bin/make.cross > > chmod +x ~/bin/make.cross > > # save the attached .config to linux build tree > > COMPILER_INSTALL_PATH=$HOME/0day GCC_VERSION=9.3.0 make.cross ARCH=sh > > > > If you fix the issue, kindly add following tag as appropriate > > Reported-by: kbuild test robot <lkp@xxxxxxxxx> > > > > All warnings (new ones prefixed by >>): > > > > In file included from kernel/trace/bpf_trace.c:10: > > kernel/trace/bpf_trace.c: In function 'bpf_seq_printf': > >>> kernel/trace/bpf_trace.c:463:35: warning: the frame size of 1672 bytes is larger than 1024 bytes [-Wframe-larger-than=] > > 463 | BPF_CALL_5(bpf_seq_printf, struct seq_file *, m, char *, fmt, u32, fmt_size, > > Thanks for reporting. Currently, I am supporting up to 12 string format > specifiers and each string up to 128 bytes. To avoid racing and helper > memory allocation, I put it on stack hence the above 1672 bytes, but > practically, I think support 4 strings with 128 bytes each is enough. > I will make a change in the next revision. It's still quite a lot of data on stack. How about per-CPU buffer that this function can use for temporary storage? > > > | ^~~~~~~~ > > include/linux/filter.h:456:30: note: in definition of macro '__BPF_CAST' > > 456 | (unsigned long)0, (t)0))) a > > | ^ > >>> include/linux/filter.h:449:27: note: in expansion of macro '__BPF_MAP_5' > > 449 | #define __BPF_MAP(n, ...) __BPF_MAP_##n(__VA_ARGS__) > > | ^~~~~~~~~~ > >>> include/linux/filter.h:474:35: note: in expansion of macro '__BPF_MAP' > > 474 | return ((btf_##name)____##name)(__BPF_MAP(x,__BPF_CAST,__BPF_N,__VA_ARGS__));\ > > | ^~~~~~~~~ > >>> include/linux/filter.h:484:31: note: in expansion of macro 'BPF_CALL_x' > > 484 | #define BPF_CALL_5(name, ...) BPF_CALL_x(5, name, __VA_ARGS__) > > | ^~~~~~~~~~ > >>> kernel/trace/bpf_trace.c:463:1: note: in expansion of macro 'BPF_CALL_5' > > 463 | BPF_CALL_5(bpf_seq_printf, struct seq_file *, m, char *, fmt, u32, fmt_size, > > | ^~~~~~~~~~ > > > > vim +463 kernel/trace/bpf_trace.c > > > > 462 > > > 463 BPF_CALL_5(bpf_seq_printf, struct seq_file *, m, char *, fmt, u32, fmt_size, > > 464 const void *, data, u32, data_len) > > 465 { > > 466 char bufs[MAX_SEQ_PRINTF_VARARGS][MAX_SEQ_PRINTF_STR_LEN]; > > 467 u64 params[MAX_SEQ_PRINTF_VARARGS]; > > 468 int i, copy_size, num_args; > > 469 const u64 *args = data; > > 470 int fmt_cnt = 0; > > 471 > [...]
