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 862DFC43458 for ; Fri, 10 Jul 2026 10:56:41 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 91C776B00A3; Fri, 10 Jul 2026 06:56:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8F4986B00A5; Fri, 10 Jul 2026 06:56:40 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 831F76B00A7; Fri, 10 Jul 2026 06:56:40 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 65C4E6B00A3 for ; Fri, 10 Jul 2026 06:56:40 -0400 (EDT) Received: from smtpin22.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay05.hostedemail.com (Postfix) with ESMTP id DE38D40430 for ; Fri, 10 Jul 2026 10:56:39 +0000 (UTC) X-FDA: 84972563718.22.37A5993 Received: from out-176.mta1.migadu.com (out-176.mta1.migadu.com [95.215.58.176]) by imf29.hostedemail.com (Postfix) with ESMTP id 3FEDA120002 for ; Fri, 10 Jul 2026 10:56:38 +0000 (UTC) Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="ON5e/gYP"; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf29.hostedemail.com: domain of usama.arif@linux.dev designates 95.215.58.176 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=1783680998; b=7kMq7BqJ9PjajLgOzmYQSNQZXB/d5o+b8iH9ASLfrXUoC+NzRinnE5nkl4HE4bG/mBFsAh u5oHlyynQeejCt6bioE+t2gvcyesYB7nmKWPu1NWI9SICd8kNqDRRm+SWhaCnlRXOPYw0y h28X6C/rDGzIGIzDqKsJ76PZGRrRlzc= ARC-Authentication-Results: i=1; imf29.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="ON5e/gYP"; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf29.hostedemail.com: domain of usama.arif@linux.dev designates 95.215.58.176 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=1783680998; 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=t/976mRd2cZjP/VBKknODLU4xXVA+kkf4lFHLX7WcpM=; b=i1/fba0lL5AdtuMcmPvVzP6DHJgnbH4PHKh9oAU8+O8aIH0QKVDTC/XnASARUw70AJgeC6 hOUe1pWCEJ2Jrbib26BIdnmMqHqwHPtYalBSBSCV/f6WW/+mnKhhrZmNm1sgWaqt6wEbpL +KhRkVIzPTzSsiU8xaHewsFrUV+6h1E= 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=1783680996; 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=t/976mRd2cZjP/VBKknODLU4xXVA+kkf4lFHLX7WcpM=; b=ON5e/gYPsrMuRZSzRp8rV82PX86lwCFqokmnB0Fb/eRWDcDOdHDA7Byw3uDGk8Qdb7SQeu GdbJtqhtHLnndIcI9s/sPXUo81ZvaKgj5rPpt4Apj4mDdRDXl182WUzkxklAZ4ewoNgWyX 37P62V9h9hG+gdAkOCdsEDWluabss4I= From: Usama Arif To: Andrew Morton , apopple@nvidia.com, balbirs@nvidia.com, baohua@kernel.org, baolin.wang@linux.alibaba.com, byungchul@sk.com, david@kernel.org, dev.jain@arm.com, gourry@gourry.net, jannh@google.com, joshua.hahnjy@gmail.com, lance.yang@linux.dev, liam@infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ljs@kernel.org, matthew.brost@intel.com, npache@redhat.com, rakie.kim@sk.com, ryan.roberts@arm.com, usama.arif@linux.dev, vbabka@kernel.org, ying.huang@linux.alibaba.com, ziy@nvidia.com, shakeel.butt@linux.dev, hannes@cmpxchg.org Cc: sashiko-bot , stable@vger.kernel.org Subject: [PATCH v3 2/3] mm/madvise: skip device-private PMDs in cold and pageout walks Date: Fri, 10 Jul 2026 03:55:22 -0700 Message-ID: <20260710105557.1987433-3-usama.arif@linux.dev> In-Reply-To: <20260710105557.1987433-1-usama.arif@linux.dev> References: <20260710105557.1987433-1-usama.arif@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 3FEDA120002 X-Rspam-User: X-Stat-Signature: 6yy6m7cebxmbookc1mo9tdmdehx3zb4c X-Rspamd-Server: rspam03 X-HE-Tag: 1783680998-401013 X-HE-Meta: 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 gjc9ZU/8 pi4W3krUXXfSCriuJkc8k0oDil/iD6s+pFXFl/CKN8e2Sc2LrGXSMARuKJ0PySJqMqCWwEOPTkvX8c1x/OBsSB7/Uarok/RtPWM+9u7fRMHsq9g+BSRVhgZkm9D7jpgFM7lRcXl0WTj3Dq7bnP+xL1ZNEdP4xs0t+9shekECFY8aKE1bdHMueJiZfdPNZsW7oBbLYkLEgTr9sVui+HeEjA5i/FCsqDNKGM16JE1Ddwu0xCq91Gmecvwg1aryzS9WGemtZWPbTbpqm5FsXzQtaw8BwHFf6jOi8VV0PRN+JfYYmqc26NenYEJ1Pp3wCDFaaf62tjDLo8DdooPXq7EHhKPIas9zLEXo4yMcy3iIpvfGdtW6VvzJeXJtY2nkRh5FW6ycbt3LsaXHHHT+tUMjcTjZ/Kw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: madvise_cold_or_pageout_pte_range() takes pmd_trans_huge_lock(), whose pmd_is_huge() check returns true for a device-private PMD. The subsequent !pmd_present() branch has a VM_BUG_ON() asserting migration is the only allowed non-present case; a device-private PMD trips it. Skip device-private PMDs in that non-present branch and continue to huge_unlock before calling pmd_folio(). Downgrade the check to VM_WARN_ON_ONCE() so an unexpected PMD softleaf logs a warning rather than panicking. Drop the thp_migration_supported() guard: it expands to IS_ENABLED(CONFIG_ARCH_SUPPORTS_PMD_SOFTLEAF), and both pmd_is_migration_entry() and pmd_is_device_private_entry() already return false when that config is not selected, so the guard suppresses only the case where the warning would already be silent. Potential trigger: an HMM-based GPU driver races with madvise(MADV_COLD)/MADV_PAGEOUT: pmd_trans_huge(*pmd) reads true, then migrate_vma_pages() flips the PMD to a device-private entry before the PMD lock is acquired. Reported-by: sashiko-bot Link: https://sashiko.dev/#/patchset/20260703173903.3789516-1-usama.arif%40linux.dev?part=6 Fixes: 368076f52ebe ("mm/huge_memory: add device-private THP support to PMD operations") Cc: Reviewed-by: Joshua Hahn Reviewed-by: Zi Yan Reviewed-by: Balbir Singh Signed-off-by: Usama Arif --- mm/madvise.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/madvise.c b/mm/madvise.c index 9292f60b19aa..c557023c3fad 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -388,8 +388,8 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd, goto huge_unlock; if (unlikely(!pmd_present(orig_pmd))) { - VM_BUG_ON(thp_migration_supported() && - !pmd_is_migration_entry(orig_pmd)); + VM_WARN_ON_ONCE(!pmd_is_migration_entry(orig_pmd) && + !pmd_is_device_private_entry(orig_pmd)); goto huge_unlock; } -- 2.53.0-Meta