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 9D902C43458 for ; Wed, 8 Jul 2026 12:20:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 606D96B008A; Wed, 8 Jul 2026 08:20:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5909E6B008C; Wed, 8 Jul 2026 08:20:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4597D6B0092; Wed, 8 Jul 2026 08:20:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 163E86B008A for ; Wed, 8 Jul 2026 08:20:51 -0400 (EDT) Received: from smtpin11.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 7E84187023 for ; Wed, 8 Jul 2026 12:20:50 +0000 (UTC) X-FDA: 84965518260.11.4054456 Received: from out-182.mta0.migadu.com (out-182.mta0.migadu.com [91.218.175.182]) by imf08.hostedemail.com (Postfix) with ESMTP id 91FDE16000E for ; Wed, 8 Jul 2026 12:20:48 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=MoRVEU5I; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf08.hostedemail.com: domain of usama.arif@linux.dev designates 91.218.175.182 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=1783513249; b=X7TQHAqkQwinpM4hUGgZTDIghVPJT3L6Ww4Ss02EtIlVw3eXoSYMNkL0gECAmjeoHZkIU8 Kyd9eQk1oR1D+OrqlpePzbjCDbjRyrwenWNrnfTZI+FG0rMUcch+0Xlls9hTR1Ce2MuZH/ KoEWn5nQ9V0wklce+fOUAmFuma6U6jI= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=MoRVEU5I; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf08.hostedemail.com: domain of usama.arif@linux.dev designates 91.218.175.182 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=1783513249; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version:content-type: content-transfer-encoding:content-transfer-encoding:in-reply-to: references:dkim-signature; bh=JE2eto0rTcmGeQDmN1z5HNPDhBhNNJkb6xZo9UCW1u4=; b=HBYCV7qhblHm9mtM6CGJS0Ag0WrWX50CX6BCaw3ebP3qqEYqA9JXZdTcanm7u8ntClbp35 3HTWckGup632oWAdb2F6qCW9JZoA6T41Ef2cWhoipQh+Hhf9KAHjRgJfLdCRQ4NvdAopir SQQwkDw5tUMutS4v+PWVrQMjJVMP9DI= 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=1783513246; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=JE2eto0rTcmGeQDmN1z5HNPDhBhNNJkb6xZo9UCW1u4=; b=MoRVEU5IKS3apV7HlZfdXtZ/WUvo7E4qL1LcnrjycfrSCQlpQGlanolDS8Xv436G4Vr+sF hJI9Mgkj5/Sl/AkpURRpVaD2lS5PFDaMf+ZmumQWuy3DC+OSjIVKwxZUKkK0Fq1LSQkayo TBEUrAKEq2AG+v6GX/ra2MBKIbl1UDY= 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 Subject: [PATCH v2 0/3] mm: handle device-private PMDs in walk callbacks Date: Wed, 8 Jul 2026 05:20:06 -0700 Message-ID: <20260708122040.861335-1-usama.arif@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 91FDE16000E X-Rspam-User: X-Stat-Signature: tf9tpx9hpsiyuxmyqp8tuz4334en7nng X-Rspamd-Server: rspam03 X-HE-Tag: 1783513248-589984 X-HE-Meta: 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 NttBrSJL QO/BkEI08VCkqWsqVW4E8dMn6kE+tes0JjWuw0HpkzGRKX3qRY4nSENFdC4+K3vYuwrbaMtAO2sE2Np5ZYuNcWMW6VsczzWdYJ+RyTsFbqU4JPUUvZtETV+HPEajN9WzquDJWTOFTe3zlFF4XexVlxkPMFIyv0rX3ejsDJgNoLmlapHRYSZi+sD3qRrTm9cGVwFIOl8x3hAq7Ge2SasFLQBUJsWfPP+1CEEuC7zfP0P7T/nOXh43DUJ7jejoxjXS9Nm2ruVlEYcNJY5Occo6i0BcyaR2hlU4VwR71plze6I83PneThC+M0nACMWNZes+nVWw4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: I have followed Joshua's suggestion in [1] for v2. The patches look different but acheive the same goal, so I have kept the Reviewed-by tags from v1. Joshua, Zi and Balbir please let me know if this wasn't ok! Since commit 368076f52ebe ("mm/huge_memory: add device-private THP support to PMD operations") a PMD may hold a device-private swap entry whenever an HMM-based GPU driver migrates an anonymous THP folio to device memory via migrate_vma_pages(). pmd_trans_huge_lock() succeeds for such PMDs (pmd_is_huge() returns true for any non-present, non-none huge PMD), so several MM walk callbacks that used to assume present THP or migration entry are now reachable with a device-private PMD. The results range from a VM_BUG_ON() firing on debug kernels, to an oops on a bogus vmemmap dereference, to silently isolating an unrelated live folio from LRU in the aliasing case. [1] https://lore.kernel.org/all/20260707191917.3213033-1-joshua.hahnjy@gmail.com/ v1 -> v2: https://lore.kernel.org/all/20260707135255.292870-1-usama.arif@linux.dev/ - Patch 1 now gates queue_folios_pmd() on !pmd_present() instead of checking only pmd_is_device_private_entry(). This matches the PTE path, keeps migration entries counted in qp->nr_failed, and skips other non-present PMDs such as device-private entries before calling pmd_folio(). (Joshua) - Patches 2 and 3 now fold device-private PMD handling into the existing !pmd_present() VM_BUG_ON() condition instead of using a separate early pmd_is_device_private_entry() check. (Joshua) - cc stable (Zi) Usama Arif (3): mm/mempolicy: skip non-present PMDs when queueing folios mm/madvise: skip device-private PMDs in cold and pageout walks mm/huge_memory: skip device-private PMDs in madvise_free_huge_pmd mm/huge_memory.c | 3 ++- mm/madvise.c | 3 ++- mm/mempolicy.c | 8 +++++--- 3 files changed, 9 insertions(+), 5 deletions(-) -- 2.53.0-Meta