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Mon, 11 Aug 2025 15:52:05 +0100 Date: Mon, 11 Aug 2025 15:52:04 +0100 Message-ID: <86v7mt9ai3.wl-maz@kernel.org> From: Marc Zyngier To: Thomas Gleixner , Coiby Xu Cc: linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, kexec@lists.infradead.org Subject: Re: [Regression] kdump fails to get DHCP address unless booting with pci=nomsi or without nr_cpus=1 In-Reply-To: <878qjq80yu.ffs@tglx> References: <87bjom8106.ffs@tglx> <878qjq80yu.ffs@tglx> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: tglx@linutronix.de, coxu@redhat.com, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, kexec@lists.infradead.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, 11 Aug 2025 14:03:21 +0100, Thomas Gleixner wrote: > > On Mon, Aug 11 2025 at 15:02, Thomas Gleixner wrote: > > CC+ Marc > > > On Mon, Aug 11 2025 at 11:23, Coiby Xu wrote: > >> Recently I met an issue that on certain virtual machines, the kdump > >> kernel fails to get DHCP IP address most of times starting from > >> 6.11-rc2. git bisection shows commit b5712bf89b4b ("irqchip/gic-v3-its: > >> Provide MSI parent for PCI/MSI[-X]") is the 1st bad commit, > >> > >> # good: [7d189c77106ed6df09829f7a419e35ada67b2bd0] PCI/MSI: Provide > >> # MSI_FLAG_PCI_MSI_MASK_PARENT > >> git bisect good 7d189c77106ed6df09829f7a419e35ada67b2bd0 > >> # good: [48f71d56e2b87839052d2a2ec32fc97a79c3e264] irqchip/gic-v3-its: > >> # Provide MSI parent infrastructure > >> git bisect good 48f71d56e2b87839052d2a2ec32fc97a79c3e264 > >> # good: [8c41ccec839c622b2d1be769a95405e4e9a4cb20] irqchip/irq-msi-lib: > >> # Prepare for PCI MSI/MSIX > >> git bisect good 8c41ccec839c622b2d1be769a95405e4e9a4cb20 > >> # first bad commit: [b5712bf89b4bbc5bcc9ebde8753ad222f1f68296] > >> # irqchip/gic-v3-its: Provide MSI parent for PCI/MSI[-X] > > > > There were follow up fixes on this, so isolating this one is not really > > conclusive. > > > > Is the problem still there on v6.16 and v6.17-rc1? Yeah, there are way too many things that have been addressed since. kdump is also a particularly nasty case, as it tends to rely on the redistributor tables programmed by the previous kernel. Also, this says "virtual machines". What's the hypervisor? How hard is it to reproduce? Thanks, M. -- Without deviation from the norm, progress is not possible.