Re: [PATCH bpf-next 1/6] bpf: implement BPF ring buffer and verifier support for it

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

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Hi Andrii,

I love your patch! Perhaps something to improve:

[auto build test WARNING on bpf-next/master]
[also build test WARNING on next-20200512]
[cannot apply to bpf/master rcu/dev v5.7-rc5]
[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://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Andrii-Nakryiko/BPF-ring-buffer/20200514-032857
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
config: riscv-rv32_defconfig (attached as .config)
compiler: riscv32-linux-gcc (GCC) 9.3.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -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=riscv 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kbuild test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

In file included from include/linux/kernel.h:11,
from include/linux/list.h:9,
from include/linux/timer.h:5,
from include/linux/workqueue.h:9,
from include/linux/bpf.h:9,
from kernel/bpf/ringbuf.c:1:
kernel/bpf/ringbuf.c: In function 'bpf_ringbuf_commit':
include/linux/compiler.h:350:38: error: call to '__compiletime_assert_155' declared with attribute error: Need native word sized stores/loads for atomicity.
350 |  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
|                                      ^
include/linux/compiler.h:331:4: note: in definition of macro '__compiletime_assert'
331 |    prefix ## suffix();             |    ^~~~~~
include/linux/compiler.h:350:2: note: in expansion of macro '_compiletime_assert'
350 |  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
|  ^~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:353:2: note: in expansion of macro 'compiletime_assert'
353 |  compiletime_assert(__native_word(t),             |  ^~~~~~~~~~~~~~~~~~
>> arch/riscv/include/asm/barrier.h:40:2: note: in expansion of macro 'compiletime_assert_atomic_type'
40 |  compiletime_assert_atomic_type(*p);             |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/asm-generic/barrier.h:157:29: note: in expansion of macro '__smp_load_acquire'
157 | #define smp_load_acquire(p) __smp_load_acquire(p)
|                             ^~~~~~~~~~~~~~~~~~
kernel/bpf/ringbuf.c:354:13: note: in expansion of macro 'smp_load_acquire'
354 |  cons_pos = smp_load_acquire(&rb->consumer_pos) & rb->mask;
|             ^~~~~~~~~~~~~~~~

vim +/compiletime_assert_atomic_type +40 arch/riscv/include/asm/barrier.h

8d235b174af5d0 Andrea Parri 2018-02-27  36  
8d235b174af5d0 Andrea Parri 2018-02-27  37  #define __smp_load_acquire(p)						\
8d235b174af5d0 Andrea Parri 2018-02-27  38  ({									\
8d235b174af5d0 Andrea Parri 2018-02-27  39  	typeof(*p) ___p1 = READ_ONCE(*p);				\
8d235b174af5d0 Andrea Parri 2018-02-27 @40  	compiletime_assert_atomic_type(*p);				\
8d235b174af5d0 Andrea Parri 2018-02-27  41  	RISCV_FENCE(r,rw);						\
8d235b174af5d0 Andrea Parri 2018-02-27  42  	___p1;								\
8d235b174af5d0 Andrea Parri 2018-02-27  43  })
8d235b174af5d0 Andrea Parri 2018-02-27  44  

:::::: The code at line 40 was first introduced by commit
:::::: 8d235b174af5d0af35ff206c15041fc2b02a0993 riscv/barrier: Define __smp_{store_release,load_acquire}

:::::: TO: Andrea Parri <parri.andrea@gmail.com>
:::::: CC: Palmer Dabbelt <palmer@sifive.com>

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

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