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Tue, 25 Aug 2026 10:08:23 +0000 (GMT) Received: from osiris (unknown [9.224.90.220]) by smtpav02.fra02v.mail.ibm.com (Postfix) with ESMTPS; Tue, 25 Aug 2026 10:08:23 +0000 (GMT) Date: Tue, 25 Aug 2026 12:08:22 +0200 From: Heiko Carstens To: Alexander Gordeev Cc: Andrey Konovalov , Gerald Schaefer , Christian Borntraeger , Vasily Gorbik , Claudio Imbrenda , Andrey Ryabinin , linux-s390@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com Subject: Re: [PATCH v7 3/4] mm/kasan: Introduce helpers for lazy MMU mode sanitizer Message-ID: <20260825100822.12095Cef-hca@linux.ibm.com> References: <52c9be0cf71a8896a5d76c148c38fb24a2005dd9.1786956464.git.agordeev@linux.ibm.com> <20260818120130.1411942A70-agordeev@linux.ibm.com> <20260824095635.11040Be5-hca@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-ORIG-GUID: vyqkNg84yn8IFtBiPCs36bkr0q50mJ_Q X-Proofpoint-Spam-Info: AW1haW4tMjYwODI1MDA4NSBTYWx0ZWRfX6MJVYSKIIeGK pJVrL9ncRX+rYf07cUoQRBtoPe9Vc7fcqeWmdBzfNODQTjwqllR9Yt5+NA7xb2Qr47a130R5V3b NJYuILE+9i4HGxxpnAM/RF2N60X5nZ0= X-Proofpoint-GUID: Tun_GKDvURKFbZzads9eFM3iYsGilwPp X-Authority-Analysis: v=2.4 cv=JZyMa0KV c=1 sm=1 tr=0 ts=6a8d699d cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=kj9zAlcOel0A:10 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=8NHveA8ksU0-wkMMO8EA:9 a=CjuIK1q_8ugA:10 a=zZCYzV9kfG8A:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODI1MDA4NSBTYWx0ZWRfX7lRVKlL+M/Qr 457OXpwPHz5uWsuTjtTsWHUcm55Ca/MaBM6cjrgMf71pQBbzQUGwd10DFxC2g7G67b8FXqDmg7e z7h7Kfy7wvOF2U8Wc4tfeBE038EFkCh6jjMT83W0ik+6kJnNgjxByTlMZjl0OFv4SVj1dZrLa82 q0prcNcm/YKfnRKyhwmgWiK4RHSqB3rDcJK9XH5AIuByGOd3WZYc+810eT0l8LRwTNxm7Sjd0rh LecvA26y+ka2EilRgfjJ+j7LgSTDH00n0nBR5KbqkqXazeZ8qBDG6mQPoS0wMlAXqyh8gcMpMYJ KFr5PPFnmm7B5QAm+iS+xkz8tFqIZl4QyCBNgBqSMoPE96MVHDJisEbd6mCbwvjxfSNIhYd9MzB i9eJepqNKpQSHOQxlTwMBpcmHB9AWTEeBCovBMcOFp0Fh+uqVPfZ6gwnLYwNBQmovBK/btIsV2U kybSlQHAKPPBnGq2D5Q== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-25_02,2026-08-24_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 clxscore=1015 adultscore=0 priorityscore=1501 impostorscore=0 malwarescore=0 bulkscore=0 lowpriorityscore=0 suspectscore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608250085 On Tue, Aug 25, 2026 at 09:50:30AM +0200, Alexander Gordeev wrote: > On Mon, Aug 24, 2026 at 11:56:35AM +0200, Heiko Carstens wrote: > > On Tue, Aug 18, 2026 at 02:01:30PM +0200, Alexander Gordeev wrote: > > > On Tue, Aug 18, 2026 at 12:11:34AM +0200, Andrey Konovalov wrote: > > > ... > > > > Hi Alexander, > > > > > > > > Should all this be limited to only s390? > > > > > > The idea is to allow any architecture to opt-in. Once [1] is accepted > > > this may look redundant, but I still see the benefit in having it. > > > > What would be the benefit if [1] is accepted? > > Just another mechanism for verification, and pretty cheap one. > I would dare to say [1] does not rule out an invalid access completely. Ok, maybe we should revisit this when we know how the solution for page table accesses will be. Then hopefully it should be quite obvious if this additional code is helpful or not.