On 05/23/2018 07:20 PM, Daniel Borkmann wrote: > On 05/23/2018 12:37 PM, Sandipan Das wrote: > [...] >> Other than that, for powerpc64, there is a problem with the way the >> binutils disassembler code (in "opcodes/ppc-dis.c") passes arguments >> to the callback fprintf_json(). >> >> In fprintf_json(), we always expect the va_list elements to resolve >> to strings (char *). But for powerpc64, the register or immediate >> operands are always passed as integers. So, when the code attempts >> to resolve these operands using va_arg(ap, char *), bpftool crashes. >> For now, I am using a workaround based on vsnprintf() but this does >> not get the semantics correct for memory operands. You can probably >> see that for the store instructions in the JSON dump above this. >> >> Daniel, >> >> Would it be okay if I send out a fix for this in a different series? > > I'm fine either way with regards to the fix. Feels like a portability bug > in the binutils disassembler? > > We could probably have a feature test like in test-disassembler-four-args > and select a workaround in bpftool based on that outcome. > > Thanks Sandipan! > > [1] tools/build/feature/test-disassembler-four-args.c >
Cool. Thanks for the tip! - Sandipan
