> Is this semantically different from the patch I posted, i.e. is there > any case which one of them covers and not the other?
Yes, the second case that I described when I said there were two cases! (Sheesh.) To repeat, when the process was doing PTRACE_SINGLESTEP and then stops on some other signal rather than because of the single-step trap (e.g. single-stepping an instruction that faults), ptrace will show TF set in its registers. With my patch, it will show TF clear. > That is an inability to set breakpoints in the vsyscall page. Andrew > told me (last May, wow) that he thought this worked in Fedora, but I > haven't seen any signs of the code. It would certainly be a Good Thing > if it is possible! Fedora kernels use a normal mapping (with randomized location) for the page, rather than the fixed high address in the vanilla kernel. The FIXADDR_USER_START area is globally mapped in a special way not using normal vma data structures, and is permanently read-only in all tasks. COW via ptrace works normally for Fedora's flavor, but no writing is ever possible to the fixmap page. Thanks, Roland - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
