2013/4/16 Oleg Nesterov <o...@redhat.com>: > On 04/16, Frederic Weisbecker wrote: >> > rc = ptrace_modify_breakpoint(bp, len, type, tsk, disabled); >> > if (rc) >> > break; >> >> It would be nice to warn here: >> >> WARN_ON_ONCE(rc && second_pass); > > Well, I disagree. > > To clarify, I agree with WARN_ON_ONCE(), but afaics it has nothing to > do with "second_pass", > >> And these are indeed supposed >> to. > > Indeed, but this is because ptrace_modify_breakpoint() should not fail. > > So, what do you think if I change the main loop above > > rc = ptrace_modify_breakpoint(...) > - if (rc) > + if (WARN_ON_ONCE(rc)) > break;
It can fail in the first pass if dr7 is incorrect. For example passing a length of 8 in x86-32 is rejected. The type can be wrong too. But the second pass shouldn't fail. If it was validated once, then it should be valid a second time. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
