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[87.80.165.179]) by smtp.gmail.com with ESMTPSA id t18-20020adff052000000b0030922ba6d0csm5274205wro.45.2023.05.19.06.22.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 19 May 2023 06:22:48 -0700 (PDT) Date: Fri, 19 May 2023 14:22:51 +0100 From: Jean-Philippe Brucker To: Marc Zyngier Cc: oliver.upton@linux.dev, james.morse@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev Subject: Re: [PATCH 0/4] KVM: arm64: vgic: Locking fixes Message-ID: <20230519132251.GA2976986@myrica> References: <20230518100914.2837292-1-jean-philippe@linaro.org> <86cz2wlnd6.wl-maz@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <86cz2wlnd6.wl-maz@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230519_062251_980580_41033DE2 X-CRM114-Status: GOOD ( 22.88 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, May 19, 2023 at 09:46:45AM +0100, Marc Zyngier wrote: > On Thu, 18 May 2023 11:09:14 +0100, > Jean-Philippe Brucker wrote: > > > > Another fun locking puzzle, between the new config_lock and srcu. > > Patch 1 attempts to fix it, and the other patches fix simpler issues. > > Thanks for that and for your excellent description of the problems. > > > I got these lockdep reports while running KVM QEMU on a TCG QEMU, but it > > can also be triggered by running the vgic_irq kselftest on TCG QEMU. > > Now, with the fix and lockdep enabled, vgic_irq hangs but I believe it's > > an unrelated weirdness: if I introduce a separate lockdep warning for > > some made up locks, then the test passes again. So I'm sending this out > > now for discussion, and will investigate that one later. > > I've taken these patches for a spin, and I cannot reproduce this hang, > though I'm running on actual HW and not QEMU. It would be really > annoying if lockdep actively introduced issues... :-/ > > Any chance you could dig into this as you have a good reproducer? I'll > try to setup a TGC environment on my end as well. Sure, I'll investigate this. All I know so far is that it is stuck somewhere in the first test_inject_preemption() Thanks, Jean _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel