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Mon, 12 May 2025 16:31:32 GMT Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 229C020114; Mon, 12 May 2025 16:31:32 +0000 (GMT) Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id ECD8020111; Mon, 12 May 2025 16:31:31 +0000 (GMT) Received: from li-008a6a4c-3549-11b2-a85c-c5cc2836eea2.ibm.com (unknown [9.155.204.135]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTPS; Mon, 12 May 2025 16:31:31 +0000 (GMT) Date: Mon, 12 May 2025 18:31:30 +0200 From: Alexander Gordeev To: Harry Yoo Cc: Andrew Morton , Andrey Ryabinin , Daniel Axtens , linux-kernel@vger.kernel.org, linux-mm@kvack.org, kasan-dev@googlegroups.com, linux-s390@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v7 1/1] kasan: Avoid sleepable page allocation from atomic context Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=DrhW+H/+ c=1 sm=1 tr=0 ts=68222267 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=kj9zAlcOel0A:10 a=dt9VzEwgFbYA:10 a=dg7Irr5rqVmvLQufYEsA:9 a=CjuIK1q_8ugA:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwNTEyMDE2NiBTYWx0ZWRfXweJ+O0011/Hs 6Hi4ZRGHDlEuF3MjSp1S3b9ZMbw7IQKKSMaelku9w/b5OsAN8qEomFNf5kouXsH7mtGlnlCEtvF uClj9wJ7drwFXTPRAGica6qa0XtOfr7AfpFn65OU1Qk88AedgaPcZzFgmtyYVTl1gdAOMd5cReN 7ObWluXXhDlPUzQ8HHQs5PSuD5d2cgz/aoNx7GOtMH38Bg5oEmGMldZdfoberwf7kt4nxgOvDcd yg0cE04WpU+7ZqSJIa7fcet/D87eDR4Byn93QV2FLuyoct/FurVgShuCbiEJIiEXK4sneVy4W1+ OUKx76PhRj/rKDEod/2dQSvFl//4ji1YxiSn+KAogptSpp/IdFODEwhyxNz29TrgwQ2Y089pOFd Am9OmqgYtKMWOWD4ynpv24Q55k8wN5Ljbtd+PP9QNcpo5/3rlNXcQgMeLbIfPFNon0jcuU1p X-Proofpoint-GUID: 13OLRlz25CD_Htxzm0V93LQo7uFLBEqY X-Proofpoint-ORIG-GUID: _K-rkFkUazgqcTHuIiwz58rCfqji_YEE X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.0.736,FMLib:17.12.80.40 definitions=2025-05-12_05,2025-05-09_01,2025-02-21_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 spamscore=0 priorityscore=1501 clxscore=1015 impostorscore=0 phishscore=0 bulkscore=0 mlxscore=0 adultscore=0 lowpriorityscore=0 suspectscore=0 mlxlogscore=597 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2504070000 definitions=main-2505120166 X-Rspamd-Server: rspam10 X-Stat-Signature: igyyzchm3dshcf6go4uu1dweys4o8c1w X-Rspamd-Queue-Id: 8952F1C0012 X-Rspam-User: X-HE-Tag: 1747067498-182400 X-HE-Meta: U2FsdGVkX19psWDVUTYKyReDSTAn24hw7bQmVZ9b02Hj24E03C8cDxgKPRoczzFG68Fr1K8DAGh2bKjIeLr9Fg147wZoSOCAOSWsXMzqcAxXx8gxH7g58uDD491LT/UvQbkfdteBB+wOG86wwQMDAJGP1ltQZFMYWd4RG/k0ZJhiX0xmW7Eg1es6M19oygyNwT2TqgVR1wbGG5XBWoo4wKzT46Edr5QnWl0O93BNxCQ3f/FulMtd5jMFqvPcb6Cd8h51aXZrrYoCvjc8QLFcfzl89ANDVt5b0+owxwZJ4G0i4kjrTk61oOpZL3TdFFfFwpjsfEbeMBJBRAHXj9KN4mK6wMyjy64v5G1pLKZameClPvcQ6yNoTGXmvGBKZ+cVnIfaLPQCDmTPMa3dVM4PBa/OP6YgaNiFQgxCGWsA7dzrIm1ZrcplbmtSmXveP7mg0M3LdKJoK4Cp4xgwpBA2ZwNveGxTnCczKzbH1EnpTTbFShKuFQGA4IqBYSiv39CYFpAUtyyQYgpsYXE7qTQKZwIa3nq/VTRn/k0QCVSKc3w6/VyMIscal0e3wbSvi9f68CDyasULM+KxN9CNGKcv6r7q14aB/BdMZ7MMMlxC4mPEw37T14iHEOroB88pyg1xu/FiCE9Z7JWW/VimfTX9r+duQaxOx6KSOGd+Oi5tXEoTX+r29qHLzlW0du8sLLOhM2ECFtU6jGbZ4LrOGSR7m3ZcRGxPy942tZ4i9ycLq9eUvwfnnEVzdEHTzTmO8qnPkIE+BrMW2qFw6oG+gdYNDRhGpVXpd0aQ2XlQ2gcuhE98YqlRXntHrUWOs0KLgBeur2ft3Vzxbi4o7pRTP5Rwt4Y7vqJp4kZbNKv8MmV+zQwv+zdphR6YwagCFvc12gte70hyLim6Avr6wjoc/Ofgrbl1RJ2cGG9/aF4D58Lio1bV5t21U9GlhKFsTWowJHJMxiu/EgpyMRCTYnZKETK jVOUihlu 4+W8t7j1GxWegb0yePgSuBc6rIVQ7cNt9kvadembI+NXMTmzf04/xW5jB6idT0kMsvstbtvnN5aEBS9CH9o/nVw61MWZ92tylM0uAgIKIQmFwkyHiYh0ZfKJUCXxyQXMiwxnaQLjeyc2HuSPQApAzFvZ76X9YFMmGWE7uVBv2nz5/QeW3MVtmC0zHTT1kp0fKhTP6BSv6q19ZpDZ/Z73wCaCKglC4o16OkqwMZS7k6iebFWiXs0G+eRm6ViSdeVQxnaHFmeFk+3IkkUiMD47539PZ/nLvq8NqSowP95gqTS3sK32EcDMOw9J6eS4p/0c4rwHCx5n7J0O9xVoVWjH2edIHIH07VJH9wCbs6XhB8QnQ8kWC+RqWAjc5P5ujUs6K8ffPCt9PijA0Zts= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, May 13, 2025 at 12:33:35AM +0900, Harry Yoo wrote: > Thanks for the update, but I don't think nr_populated is sufficient > here. If nr_populated in the last iteration is smaller than its value > in any previous iteration, it could lead to a memory leak. > > That's why I suggested (PAGE_SIZE / sizeof(data.pages[0])). > ...but on second thought maybe touching the whole array is not > efficient either. Yes, I did not like it and wanted to limit the number of pages, but did not realize that using nr_populated still could produce leaks. In addition I could simply do: max_populted = max(max_populted, nr_populated); ... free_pages_bulk(data.pages, max_populated); > If this ends up making things complicated probably we should just > merge v6 instead (v6 looks good)? micro-optimizing vmalloc shadow memory > population doesn't seem worth it if it comes at the cost of complexity :) v6 is okay, except that in v7 I use break instead of return: ret = apply_to_page_range(...); if (ret) break; and as result can call the final: free_page((unsigned long)data.pages); Frankly, I do not have strong opinion. > -- > Cheers, > Harry / Hyeonggon Thanks!