On 11/13/20 11:36 AM, Björn Töpel wrote: > I was running the selftest/bpf on riscv, and had a closer look at one > of the failing cases: > > #14/p valid read map access into a read-only array 2 FAIL retval > 65507 != -29 (run 1/1) > > The test does a csum_partial() call via a BPF helper. riscv uses the > generic implementation. arm64 uses the generic csum_partial() and fail > in the same way [1]. arm (32-bit) has a arch specfic implementation, > and fail in another way (FAIL retval 131042 != -29) [2]. > > I mimicked the test case in a userland program, comparing the generic > csum_partial() to the x86 implementation [3], and the generic and x86 > implementation does yield a different result. > > x86 : -29 : 0xffffffe3 > generic : 65507 : 0x0000ffe3 > arm : 131042 : 0x0001ffe2 > > Who is correct? :-) It would be nice to get rid of this failed case... > There are all the same value :), they all fold to u16 0xFFE3 Maybe the test needs a fix, there is a missing folding. > > Thanks, > Björn > > > [1] https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20201112/testrun/3430401/suite/kselftest/test/bpf.test_verifier/log > [2] https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v5.10-rc3-207-g585e5b17b92d/testrun/3432361/suite/kselftest/test/bpf.test_verifier/log > [3] https://gist.github.com/bjoto/dc22d593aa3ac63c2c90632de5ed82e0 >
