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 848BEC44506 for ; Fri, 10 Jul 2026 15:02:15 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 85F726B00AA; Fri, 10 Jul 2026 11:02:14 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8102D6B00AD; Fri, 10 Jul 2026 11:02:14 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 701CC6B00AE; Fri, 10 Jul 2026 11:02:14 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 494166B00AA for ; Fri, 10 Jul 2026 11:02:14 -0400 (EDT) Received: from smtpin12.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay10.hostedemail.com (Postfix) with ESMTP id D077CC360A for ; Fri, 10 Jul 2026 15:02:13 +0000 (UTC) X-FDA: 84973182546.12.05D567D Received: from out-189.mta1.migadu.com (out-189.mta1.migadu.com [95.215.58.189]) by imf15.hostedemail.com (Postfix) with ESMTP id 32526A0004 for ; Fri, 10 Jul 2026 15:02:12 +0000 (UTC) Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=MZROCy6l; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf15.hostedemail.com: domain of usama.arif@linux.dev designates 95.215.58.189 as permitted sender) smtp.mailfrom=usama.arif@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1783695732; 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-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=aZI5LYV42PS6biPr4EpPtmNA2/Ct3B0vmxWhVv67hMQ=; b=Pr0W/E941YUXXK56xMKpJgUxb30U+44amu0mKpZd21PiSqmjuldKQvGZFoWktEedaofegs wz1FI6/L3cZsMTywvNEEuc+cg7uKkpwXz/U/DL1WAaPbhroe6pSo6lL1jkDYrdUreJ+ujR dhsHWO8IXWXeFs7BAlR2lMFc6IPaG+g= ARC-Authentication-Results: i=1; imf15.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=MZROCy6l; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf15.hostedemail.com: domain of usama.arif@linux.dev designates 95.215.58.189 as permitted sender) smtp.mailfrom=usama.arif@linux.dev ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1783695732; b=IS3ceh5Y/dsMhC4Qw1jxMKhg8ofe5VdEHm551jRx2jv4key1lOkI2wmI2VC3LSzw9pB687 uLIwoWNI1kDaqdFY/pWYTOnApqESOkKJQ/v3+wCUYD/SlpA4EwyF0bsRGQOAXec8TNUz1T EucxfL+iqtX87ucNJ5oNMlDdFGVK8so= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1783695730; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=aZI5LYV42PS6biPr4EpPtmNA2/Ct3B0vmxWhVv67hMQ=; b=MZROCy6lL1QQmCPfIUisZeY0kM2GabQXwOtIPP3A3cm+RMRXSOgYac6UptYGQ7VhqXNeyw wtutsvb8aPqVZi6zc3EgSwoO0ln7YS4KO4nhj6JIKdxo8xv2KVisPl5jAXmGHUZKQ/nqtB 2NYd28az7X/hUd6bbc+c0FbG1Akn/0M= From: Usama Arif To: "Matthew Wilcox (Oracle)" Cc: Usama Arif , Andrew Morton , Jane Chu , linux-mm@kvack.org, Muchun Song , Oscar Salvador , David Hildenbrand , Miaohe Lin , Naoya Horiguchi , Jan Kara , linux-fsdevel@vger.kernel.org, Christian Brauner Subject: Re: [PATCH v2 06/10] memory-failure: Prevent UAF in raw_hwp_page list Date: Fri, 10 Jul 2026 08:02:03 -0700 Message-ID: <20260710150204.1887475-1-usama.arif@linux.dev> In-Reply-To: <20260709184740.1286561-7-willy@infradead.org> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 32526A0004 X-Stat-Signature: qojse8qu4zzxmce6yeizb7b1pcgkekgc X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1783695732-21688 X-HE-Meta: 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 WESnediu vXWF06f9lJE34VuALepVU67e6OI0u8CCXoq1qYrmww40Mgp1Z4cGkOF17B1AydhnJC2ayQ5ZXB/vEM0NnvezkjT6R7sthQ1Ve24ko8rh57AGh5AgQjV/cWmc3Ecw45aHuH6bIf10AU66ks5ddWwmOHAsjOe01P1AMc24PWsbAxXs7OFkjKVacV+S5vX0UcvGWIgQ23AeNjGZ0jkxFHzdLn6Mq8CYkAAenK0ybRTxl0tCAh/kVz1i3ETNz7EVwI6v5G8eiSWbLgMz3oCGntDKP0ap2BNpX/YnpS5mqLm8VpQFlj9mDYdMBFvJCj/Cy41qXRxRJyoQnXZ01elYozDe9N0sUhceOEL3ANefPjcJXy10oYxtT9j+OUnwTMEID25KfCjkg Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, 9 Jul 2026 19:47:34 +0100 "Matthew Wilcox (Oracle)" wrote: > Most accesses to the raw_hwp_page list are protected by mf_mutex. > However, the call to folio_clear_hugetlb_hwpoison() in mm/hugetlb.c > does not. This is probably OK today as this is in the freeing path and > I think all current calls to is_raw_hwpoison_page_in_hugepage() hold a > reference to the folio. However, the next patch will call this function > without holding a reference on the folio, which will expose this race. > > Rename the current folio_clear_hugetlb_hwpoison() to > __folio_clear_hugetlb_hwpoison() and wrap it with a new > folio_clear_hugetlb_hwpoison() for the benefit of external callers. > > Signed-off-by: Matthew Wilcox (Oracle) > --- > mm/memory-failure.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index 53063e2a1f97..353288cce1b2 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -1935,7 +1935,7 @@ static unsigned long folio_free_raw_hwp(struct folio *folio, bool move_flag) > return __folio_free_raw_hwp(folio, move_flag); > } > > -void folio_clear_hugetlb_hwpoison(struct folio *folio) > +static void __folio_clear_hugetlb_hwpoison(struct folio *folio) > { Good to add lockdep_assert_held(&mf_mutex) here, but there is a issue below. > if (folio_test_hugetlb_raw_hwp_unreliable(folio)) > return; > @@ -1945,6 +1945,13 @@ void folio_clear_hugetlb_hwpoison(struct folio *folio) > folio_free_raw_hwp(folio, true); > } > > +void folio_clear_hugetlb_hwpoison(struct folio *folio) > +{ > + mutex_lock(&mf_mutex); This wrapper can now sleep, but its external caller is the hugetlb free path. __update_and_free_hugetlb_folio() is reached from update_and_free_hugetlb_folio(), which has a comment saying "Defer freeing to avoid using GFP_ATOMIC" > + __folio_clear_hugetlb_hwpoison(folio); > + mutex_unlock(&mf_mutex); > +} > + > static int get_huge_page_for_hwpoison(unsigned long pfn, int flags, > bool *migratable_cleared) > { > @@ -2051,7 +2058,7 @@ static int try_memory_failure_hugetlb(unsigned long pfn, int flags) > folio_lock(folio); > > if (hwpoison_filter(p)) { > - folio_clear_hugetlb_hwpoison(folio); > + __folio_clear_hugetlb_hwpoison(folio); > if (migratable_cleared) > folio_set_hugetlb_migratable(folio); > folio_unlock(folio); > -- > 2.47.3 > >