labath added a comment. In D117928#3265048 <https://reviews.llvm.org/D117928#3265048>, @ljmf00 wrote:
> In D117928#3263992 <https://reviews.llvm.org/D117928#3263992>, @mgorny wrote: > >> Thank you. Yes, please test on an older kernel, in case it's specifically a >> kernel regression. > > I can confirm regression on Linux LTS 5.10.93. Probably later and introduced > by the patch I mentioned. I reported to the kernel bug tracker. See > https://bugzilla.kernel.org/show_bug.cgi?id=215524 . > > In D117928#3264795 <https://reviews.llvm.org/D117928#3264795>, @labath wrote: > >> If this is a problem with PTRACE_SETREGSET(NT_FPREGSET), then we might be >> able to work around it by using PTRACE_POKEUSER instead. But it'd definitely >> be good to confirm this, so that we can report the bug to kernel devs. > > According to `ptrace` documentation `PTRACE_SETFPREGS` seems a better fit, > although either this and `PTRACE_POKEUSER` disallow writing in some specific > general-purpose registers, so we should only use this for FP/XMM registers? I think either would be fine, if it works (I'm not sure how early the PTRACE_SETFPREGS and PTRACE_SETREGSET codepaths converge inside the kernel). I wouldn't be too worried about the write prohibition clause. I'm pretty sure that applies to things like setting the single-step bit inside the flags register, and similar mischief that could confuse/crash the kernel. Those restrictions should be enforced for any register-writing method. And now, thanks to @mgorny, we actually have tests that would catch situations when we're not able to change some register. If you want, I can try to create a patch for this, though it might take me a couple of days to get around to it. > AFAIK BSD-based kernels implements `PT_SETXMMREGS` although I don't see any > documentation on the Linux kernel side about this. Yeah, linux doesn't have those. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D117928/new/ https://reviews.llvm.org/D117928 _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
