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On 11/04, Will Deacon wrote: > > > > @@ -588,7 +584,7 @@ static void update_syscall_orig_x0_after_ptrace(struct task_struct *target) > > > * Don't update orig_x0 for a syscall-exit-stop, as x0 now contains the > > > * return value of the system call. > > > */ > > > - if ((info->si_code & ~0x80) == SIGTRAP && > > > + if (info && (info->si_code & ~0x80) == SIGTRAP && > > > target->ptrace_message == PTRACE_EVENTMSG_SYSCALL_EXIT) { > > > return; > > > > LGTM, but I don't understand this arm-specific code. > > Welcome to the club :) Thank you ;) > The original rationale is described in e057b9477232 ("arm64: syscall: > Ensure saved x0 is kept in-sync with tracer updates"), so hopefully that > helps to set the scene. [...snip...] Thanks for your explanations. Yes, I tried to read that and other commits. The only result is that I've managed to convinced myself that more or less I understand why 88b839ce497c and 5a87e8c7f3702 make sense. > So that's the mess we're in and I'm all ears if there's a cleaner way to > sort it out without breaking anything that relies on the fragile semantics > we already have. No, I can't suggest anything better. I think your patches and the fix from Zhao are fine. ---------------------------------------------------------------------------- Now the question... So we had CVE-2026-68171 and then it was rejected: https://lore.kernel.org/linux-cve-announce/2026081123-REJECTED-f1f0@gregkh/ Now we have another one, CVE-2026-90347 https://lore.kernel.org/linux-cve-announce/2026091703-CVE-2026-90347-6f2c@gregkh/ Why? To me the problem looks minor (security wise). Yes, a malicious debugger can fool seccomp. So what? What is the real problem from the scurity perspective? Oleg.