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McKenney" , Thomas Gleixner Subject: Re: [RFC PATCH 05/20] context_tracking: Always inline the empty stubs called from noinstr code Message-ID: <20261028135251.GS2668564@noisy.programming.kicks-ass.net> References: <20261028120034.871983-1-sashal@kernel.org> <20261028120034.871983-6-sashal@kernel.org> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261028120034.871983-6-sashal@kernel.org> On Wed, Oct 28, 2026 at 07:59:29AM -0400, Sasha Levin wrote: > The !CONFIG_CONTEXT_TRACKING_USER versions of user_enter_irqoff() and > user_exit_irqoff(), and the !CONFIG_CONTEXT_TRACKING_IDLE versions of > ct_idle_enter() and ct_idle_exit(), are plain static inline functions, > while their real counterparts are __always_inline (user_*_irqoff()) or > noinstr (ct_idle_*()) functions. They are called from noinstr code, so > when they aren't inlined that's a call leaving the noinstr section. This > happens with code coverage instrumentation, which makes the compiler > refuse to inline an instrumented function into a noinstr one: > > vmlinux.o: warning: objtool: do_syscall_64+0x81: call to user_exit_irqoff() leaves .noinstr.text section > > Make the stubs __always_inline as well. Ah yes, nothing beats adding instrumentation to empty functions :-)