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
