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Peter Anvin" , Andrew Donnellan , Mark Rutland , Michal =?utf-8?Q?Such=C3=A1nek?= , Arnd Bergmann , Jiaxun Yang , Ryan Roberts , Greg Kroah-Hartman , Mukesh Kumar Chaurasiya , Shrikanth Hegde , Zong Li , Nam Cao , Deepak Gupta , Lukas Gerlach , Rui Qi , Kees Cook , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org Subject: Re: [RFC] entry: Untangle the return value of syscall_enter_from_user_mode from syscall NR In-Reply-To: References: Date: Mon, 06 Jul 2026 10:16:57 +0200 Message-ID: <87ik6sjzwm.ffs@fw13> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On Wed, Jul 01 2026 at 19:42, Michal Such=C3=A1nek wrote: >=20=20 > if (unlikely(work & SYSCALL_WORK_SYSCALL_TRACEPOINT)) > - syscall =3D trace_syscall_enter(regs, syscall); > + *syscall =3D trace_syscall_enter(regs, *syscall); >=20=20 > - syscall_enter_audit(regs, syscall); > + syscall_enter_audit(regs, *syscall); >=20=20 > - return ret ? : syscall; > + return 0; That breaks trace_syscall_enter() because the probes/BPF muck attached ot that can: 1) set the return code 2) set syscall to -1L That works correctly today, but with your sloppy hackery the low level x86 code falls into sys_ni_syscall() which sets the return code to -ENOSYS.