Messages in this thread | | | Date | Fri, 31 Dec 2004 00:36:18 -0500 | From | Daniel Jacobowitz <> | Subject | Re: ptrace single-stepping change breaks Wine |
| |
On Thu, Dec 30, 2004 at 03:17:01PM -0800, Linus Torvalds wrote: > > > On Thu, 30 Dec 2004, Daniel Jacobowitz wrote: > > > > does not look right to me. Before, we'd get an 0x80|SIGTRAP result > > from wait. Now, you've moved the 0x80 to live only inside the siginfo. > > This is accessible to the debugger via ptrace, but only very recently > > (late 2.5.x). So this will probably break users of PT_TRACESYSGOOD. > > I don't see how to easily emulate the old behaviour 100% - see > ptrace_notify. We always sent the signal SIGTRAP to the process, and then > set "exit_code" tp have the 0x80 marker by calling ptrace_stop() by hand. > However, if we make it a real signal (which we need to do to get the > continue semantics right), we no longer have that out-of-band info > available to us. > > We could make "get_signal_to_deliver()" pass in some other exit_code to > ptrace_stop() than just signr. It would have to pick it up from the > siginfo structure, but then we'd have to make sure that _other_ signal > users do that properly.. > > Patches/suggestions welcome.
Well, you put SIGTRAP|0x80 in si_code. Coincidentally, 0x80 is SI_KERNEL. So testing for SI_KERNEL | 0x80 is probably OK in the signal path, since most of its other arbitrary values would be either negative or not include SI_KERNEL.
-- Daniel Jacobowitz - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |