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b=dh2ykrRTucW/VBrxB9M+J/VOLxuu8Lp95gVoTmE/Xe1V/jHHEAVNrNpBPWO+ZIBXt HG+X8VMiuLB4EZ9AKx7hjBsSp++azCCCIWW/C337n6ePgDj45+2IvH3Ms3ctzZQW8X kvD21TM/G5banmvITBwHlXzBgWdEgf/b1ajmy+3+asmEKFWAckNYgoCcpZDiOphpcd VC4WI0myBdBHSmnabwjUPsIaXePp2p6H2sRRuYtoNlLoX2MW8n0pjYjQBDi2OQDdYV ngTsYJmUH7nO8cyxfaaE2MM+N/yece/OeonxsgVKvveXcZwK+8IYV6OXIHuwG+j4Oy r4gBfxReXLBmQ== Date: Tue, 7 Jul 2026 13:47:14 +0100 From: Lorenzo Stoakes To: Russell King Cc: Qi Xi , Xie Yuanbin , akpm@linux-foundation.org, david@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, linusw@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, sunnanyong@huawei.com, linux-mm@kvack.org, lilinjie8@huawei.com, liaohua4@huawei.com Subject: Re: [PATCH v3 1/2] ARM: mm: fix use-after-free in __do_user_fault() under CONFIG_DEBUG_USER Message-ID: References: <20260626073048.3595106-2-xiqi2@huawei.com> <20260706133247.145485-1-xieyuanbin1@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: EBDC1180004 X-Rspam-User: X-Stat-Signature: bdmkhcup7eh8f6d67fox3frs3zrj7c6k X-Rspamd-Server: rspam03 X-HE-Tag: 1783428445-265113 X-HE-Meta: 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 qjhpaNNA btIFWU1vzqdCOAmF/SVdbXpDWCzzop9IkDDIy0+3X2LWmaRaGlVRlSQeUtkfQrirXUNpkbd4LW//bztAWSbTCDmYLX7eI7sdNTf06knUhKNdI4vdhMPA+SJLzIssFy9JrbclVMkHC3jAs0xzNKXvh+CUDoLdM0Ecxi+XUF0wxlokT3/HfJJd+Fbrkk6yTlCC2HbDEKkbOVPncQ2m3zXsPxlR1d3fw3Yk8x+WlDjLzC8Y5LzGJm24lSztUOP9UKL8n5kb4h4ntpgr6NR4pEdt0SxdNf2+YpO1GMggQK0qIujFy3qwpOuJ8SXgWe9Gh9SWwU+wEyAnKLcHht7V0cAHhBDlCywmWBTdsNJPb6gMg6RAwXBU= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Jul 07, 2026 at 12:57:45PM +0100, Russell King wrote: > On Tue, Jul 07, 2026 at 07:48:12PM +0800, Qi Xi wrote: > > You're right. And I think the fix is to simply skip show_pte() for kernel > > addresses. > > No. This information is useful debug for kernel oops. Yup see my reply, just upgrade it to an mmap write lock and you should be safe to keep this. > > -- > RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ > FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last! Cheers, Lorenzo