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Thu, 5 Nov 2026 06:38:09 -0500 (EST) Date: Thu, 5 Nov 2026 11:38:08 +0000 From: Kiryl Shutsemau To: Usama Arif Cc: Catalin Marinas , Will Deacon , Mark Rutland , James Morse , Marc Zyngier , Doug Anderson , Breno Leitao , Dawei Li , mrigendrachaubey , kernel-team@meta.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH 1/2] arm64: sdei: Run the event handler on the kernel vectors Message-ID: References: <20261104180936.2981070-2-kas@kernel.org> <20261104182842.3436759-1-usama.arif@linux.dev> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261104182842.3436759-1-usama.arif@linux.dev> X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-5.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Wed, Nov 04, 2026 at 10:28:41AM -0800, Usama Arif wrote: > Would doing the swap in __sdei_handler(), around the whole NMI > entry and exit pair, close that window? Yes. The WARNs you point at only fire when context tracking is already broken, but the same window has tracepoints: trace_hardirqs_off_finish() fires irq_disable exactly when the event lands in user space, and a BPF program attached there can fault. It applies to 2/2 too: anything that traps in irqentry_nmi_enter() overwrites ELR, ESR and FAR before do_sdei_event() saves them. I'll move both into __sdei_handler(), around irqentry_nmi_enter() and irqentry_nmi_exit(), in v2. do_sdei_event() still needs the interrupted VBAR for the IRQ-like resume, so it will get it as an argument. -- Kiryl Shutsemau / Kirill A. Shutemov