From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6477DCD3424 for ; Wed, 6 May 2026 05:17:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8FAC76B008A; Wed, 6 May 2026 01:17:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8AA2F6B0092; Wed, 6 May 2026 01:17:38 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 799936B0093; Wed, 6 May 2026 01:17:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 658B96B008A for ; Wed, 6 May 2026 01:17:38 -0400 (EDT) Received: from smtpin15.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay04.hostedemail.com (Postfix) with ESMTP id F35CC1A074E for ; Wed, 6 May 2026 05:17:37 +0000 (UTC) X-FDA: 84735837354.15.A4FAB93 Received: from out30-113.freemail.mail.aliyun.com (out30-113.freemail.mail.aliyun.com [115.124.30.113]) by imf21.hostedemail.com (Postfix) with ESMTP id 4EA5F1C000F for ; Wed, 6 May 2026 05:17:34 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=linux.alibaba.com header.s=default header.b=gPOBWIOv; dmarc=pass (policy=none) header.from=linux.alibaba.com; spf=pass (imf21.hostedemail.com: domain of baolin.wang@linux.alibaba.com designates 115.124.30.113 as permitted sender) smtp.mailfrom=baolin.wang@linux.alibaba.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1778044656; a=rsa-sha256; cv=none; b=sX622kiBQ6KRFcrIEVjkeBWzXW7sTc7wqGCgqRyUbVvWM15jq/cGlv0oSYCviHu3mXeBzm GB7Lzo7D+qLkUi/aCizi5pQfFEE7ojTpPWiQyGUtd8DqPgzbDHbZ+rJHK1lZcr8C6KnmcO KDi93eHgG4IA28usRwMRl8S0b26gdhM= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=linux.alibaba.com header.s=default header.b=gPOBWIOv; dmarc=pass (policy=none) header.from=linux.alibaba.com; spf=pass (imf21.hostedemail.com: domain of baolin.wang@linux.alibaba.com designates 115.124.30.113 as permitted sender) smtp.mailfrom=baolin.wang@linux.alibaba.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1778044656; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=gffulxOArRAipIgbJlt1HnidYx/4fODZLq6S9dioK+E=; b=Mx3NYVnOZU4OoutvdclhD82fsTl0V9DBlJgAW5zDiNK597lXcqJ2cRzbClCEBhAcyMXu95 /TN/87D583P+uDt0uPJLsQcldaQeaMxXEtfbLSQ97fID95paOyH6N8L+w+/7jGQJHyuWy/ QprWOzNNGZUpTPWUkeBcRSTs1rCR1tk= DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1778044652; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=gffulxOArRAipIgbJlt1HnidYx/4fODZLq6S9dioK+E=; b=gPOBWIOvz1DyTwUgHIuveSW4DjWnn46rztCC6TtMg/J7ju7Y+neBF45CM8QDZUluOsS2LC4VRvpFbKndbAn45pLJftcewkfk5+ro2FVuRi3Ic0cIsnQI5UsPQ48xgZVgc0DT+DAp+0mrkp6mkj3u3q4UyJN9oUIMAA3V7CjvUb0= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R111e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam033037033178;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=16;SR=0;TI=SMTPD_---0X2L3DDf_1778044649; Received: from 30.221.149.158(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0X2L3DDf_1778044649 cluster:ay36) by smtp.aliyun-inc.com; Wed, 06 May 2026 13:17:30 +0800 Message-ID: <8fa3ddff-b717-4804-b524-9b2c0447c60c@linux.alibaba.com> Date: Wed, 6 May 2026 13:17:29 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] mm/khugepaged: clear MMF_VM_HUGEPAGE on mm_slot_alloc() failure To: Ye Liu , Andrew Morton , David Hildenbrand , Lorenzo Stoakes , Xin Hao Cc: Ye Liu , Zi Yan , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260506012130.9306-1-ye.liu@linux.dev> From: Baolin Wang In-Reply-To: <20260506012130.9306-1-ye.liu@linux.dev> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Stat-Signature: ww8pf11ckf6b7wxf6mksqix5yh3p9r7k X-Rspam-User: X-Rspamd-Queue-Id: 4EA5F1C000F X-Rspamd-Server: rspam07 X-HE-Tag: 1778044654-432304 X-HE-Meta: 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 CbnyWDLz QJKMFAs02vriYkgnoW1G8l+IiJsP1k1hPeSC719nuae53yPX/0N2WWhk77uRvJ+jU8kj+4Sdfd7i20zLdVtayaQZMWvEmRvoZl+4Lnva4yLZ41LToCw0A+XNpJOJb/PCms2RInJntAUVWq0YcNGb45vcvrpPgDIBkC2V5fKgY32CBbBmGMCEQXqccMBgFZ1fk5Y2f8rJpRjk4riFZOn1DbnPVLPIisFtkHukW1lC9K/lbjS6om2CgfRQ2ZL7QTuQQAdYi2U68yU+qOuvQ3nwNYGSR4tiLwJ+aPu/5x9mCIcj5JFzCzj2yZJukYoHPJjdsnBGJcGR6C9zwG9ml8ao4tVlSgRhtzXdmEQ66Z1tuhHDqtbgivas5K4n9RQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 5/6/26 9:21 AM, Ye Liu wrote: > From: Ye Liu > > __khugepaged_enter() sets MMF_VM_HUGEPAGE before allocating the > corresponding mm_slot. If mm_slot_alloc() fails, the function > returns with the flag set but without inserting the mm into the > khugepaged tracking structures. > > This leaves the mm in an inconsistent state: it is marked as > registered (MMF_VM_HUGEPAGE set), but will never be scanned by > khugepaged. Future attempts to register the mm are skipped since > khugepaged_enter_vma() checks the flag and returns early. > > Fix this by clearing MMF_VM_HUGEPAGE when mm_slot_alloc() fails, > restoring the ability to retry registration later. > > Fixes: 16618670276a ("mm: khugepaged: avoid pointless allocation for struct mm_slot") > Signed-off-by: Ye Liu > --- Good catch. Feel free to add: Reviewed-by: Baolin Wang