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[209.132.180.67]) by mx.google.com with ESMTP id 191si4924130pgh.596.2019.05.16.06.43.34; Thu, 16 May 2019 06:43:51 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727069AbfEPNlK (ORCPT + 99 others); Thu, 16 May 2019 09:41:10 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:46240 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726528AbfEPNlK (ORCPT ); Thu, 16 May 2019 09:41:10 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E85DB1715; Thu, 16 May 2019 06:41:09 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 912F83F575; Thu, 16 May 2019 06:41:08 -0700 (PDT) Date: Thu, 16 May 2019 14:41:06 +0100 From: Mark Rutland To: Christoph Hellwig Cc: linux-kernel@vger.kernel.org, Steven Price , Mike Rapoport , Andrew Morton , Will Deacon , Catalin Marinas Subject: Re: Bad virt_to_phys since commit 54c7a8916a887f35 Message-ID: <20190516134105.GB43059@lakrids.cambridge.arm.com> References: <20190516133820.GA43059@lakrids.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190516133820.GA43059@lakrids.cambridge.arm.com> User-Agent: Mutt/1.11.1+11 (2f07cb52) (2018-12-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 16, 2019 at 02:38:20PM +0100, Mark Rutland wrote: > Hi, > > Since commit: > > 54c7a8916a887f35 ("initramfs: free initrd memory if opening /initrd.image fails") Ugh, I dropped a paragarph here. Since that commit, I'm seeing a boot-time splat on arm64 when using CONFIG_DEBUG_VIRTUAL. I'm running an arm64 syzkaller instance, and this kills the VM, preventing further testing, which is unfortunate. Mark. > IIUC prior to that commit, we'd only attempt to free an intird if we had > one, whereas now we do so unconditionally. AFAICT, in this case > initrd_start has not been initialized (I'm not using an initrd or > initramfs on my system), so we end up trying virt_to_phys() on a bogus > VA in free_initrd_mem(). > > Any ideas on the right way to fix this? > > Thanks, > Mark. > > [ 5.251023][ T1] ------------[ cut here ]------------ > [ 5.252465][ T1] virt_to_phys used for non-linear address: (____ptrval____) (0x0) > [ 5.254388][ T1] WARNING: CPU: 0 PID: 1 at arch/arm64/mm/physaddr.c:15 __virt_to_phys+0x88/0xb8 > [ 5.256473][ T1] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.1.0-11058-g83f3ef3 #4 > [ 5.258513][ T1] Hardware name: linux,dummy-virt (DT) > [ 5.259923][ T1] pstate: 80400005 (Nzcv daif +PAN -UAO) > [ 5.261375][ T1] pc : __virt_to_phys+0x88/0xb8 > [ 5.262623][ T1] lr : __virt_to_phys+0x88/0xb8 > [ 5.263879][ T1] sp : ffff80000be4fc60 > [ 5.264941][ T1] x29: ffff80000be4fc60 x28: 0000000040000000 > [ 5.266522][ T1] x27: ffff200015445000 x26: 0000000000000000 > [ 5.268112][ T1] x25: 0000000000000000 x24: ffff2000163e0000 > [ 5.269691][ T1] x23: ffff2000163e0440 x22: ffff2000163e0000 > [ 5.271270][ T1] x21: ffff2000163e0400 x20: 0000000000000000 > [ 5.272860][ T1] x19: 0000000000000000 x18: ffff200016aa0f80 > [ 5.274430][ T1] x17: ffff2000153a0000 x16: 00000000f2000000 > [ 5.276018][ T1] x15: 1fffe40002d5560d x14: 1ffff00007716109 > [ 5.277596][ T1] x13: ffff200016e17000 x12: ffff040002a83fd9 > [ 5.279179][ T1] x11: 1fffe40002a83fd8 x10: ffff040002a83fd8 > [ 5.280765][ T1] x9 : 1fffe40002a83fd8 x8 : dfff200000000000 > [ 5.282343][ T1] x7 : ffff040002a83fd9 x6 : ffff20001541fec0 > [ 5.283929][ T1] x5 : ffff80003b8b0040 x4 : 0000000000000000 > [ 5.285509][ T1] x3 : ffff2000102c6504 x2 : ffff1000017c9f54 > [ 5.287091][ T1] x1 : 15eab2dadba38000 x0 : 0000000000000000 > [ 5.288678][ T1] Call trace: > [ 5.289532][ T1] __virt_to_phys+0x88/0xb8 > [ 5.290701][ T1] free_initrd_mem+0x3c/0x50 > [ 5.291894][ T1] populate_rootfs+0x2f4/0x358 > [ 5.293123][ T1] do_one_initcall+0x568/0xb94 > [ 5.294349][ T1] kernel_init_freeable+0xd44/0xe2c > [ 5.295695][ T1] kernel_init+0x14/0x1c0 > [ 5.296814][ T1] ret_from_fork+0x10/0x1c > [ 5.297947][ T1] irq event stamp: 288672 > [ 5.299069][ T1] hardirqs last enabled at (288671): [] console_unlock+0x89c/0xe50 > [ 5.301521][ T1] hardirqs last disabled at (288672): [] do_debug_exception+0x268/0x3e0 > [ 5.304061][ T1] softirqs last enabled at (288668): [] __do_softirq+0xa38/0xf48 > [ 5.306457][ T1] softirqs last disabled at (288653): [] irq_exit+0x2a4/0x318 > [ 5.308777][ T1] ---[ end trace 3cf83e3c184a4d3e ]---