From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qv1-f48.google.com (mail-qv1-f48.google.com [209.85.219.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 43ED115A85A for ; Sat, 12 Sep 2026 03:48:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.48 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789184920; cv=none; b=ug0YNCgrkKE3yyTHU0wWwyiWcPWEP8lvC7sZObzrMV/9WYCOZ/DbSYcJwRZYV5V8yNRZIy47mfA00h1fkNUVkApr/yuJkmU6SQg893eUuSrC17FEtgMYtzJMre02y9WRBEir7TGIBJf7/EcWfDZdtxasuzsZUrII23Q436n8TEY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789184920; c=relaxed/simple; bh=uYFJnnnm2NR9mXD5b/fiPbuo/WUiVhKYOc1vVeIcaro=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QmamkQIxmgONtpXIrVL5T4EiFmXikKPvAtp8g9Cokv4jUV0agpWwIr2o6B6Rby+BplO+D4EKqMAjzOk+vGb2WBIqKDEfT3wqw3GA44RVRwZFWUoTwSxAKiKZoAs3buN/rforKdNVtVLPZpPnzVsxHB6ivUzK81+YhPXvcAk8uro= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=gourry.net; spf=pass smtp.mailfrom=gourry.net; dkim=pass (2048-bit key) header.d=gourry.net header.i=@gourry.net header.b=LD2AAdjF; arc=none smtp.client-ip=209.85.219.48 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=gourry.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gourry.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gourry.net header.i=@gourry.net header.b="LD2AAdjF" Received: by mail-qv1-f48.google.com with SMTP id 6a1803df08f44-90e970f710cso16997486d6.3 for ; Fri, 11 Sep 2026 20:48:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gourry.net; s=google; t=1789184918; x=1789789718; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=5SE/qOas+/SI2EvNxtEJVx4SSxOPMNxV+dkdmLC2H+E=; b=LD2AAdjFCN0FPQA8tvBoez0vdfwDEQZQCk8JOq11DdDmz1R+Ia0Xcj7+Gn7EN63vom RGDIduyByP5MUffxetSnY78Am+ZOWhrR1MkhPW1i3r0nMDmi49GD3ivE63x3b2nOUZAO lGB5igjWUC7nSmDzmzLUQy61TnGGXyXSN7UcwTdC+g4aGfKXLFgIbeqBBvN/KEFGCMqN b25Q4aiJ1CVNKZe2ne8qKqwfXLcP63fpy54ZL96e4f9ztTWDtNqvDSLzxngwQ1uQlfVL XyE9Q3VwG6YeUs4Y4+ranF5CNmAZ/DGbbvfS4B0dL36cl342FvrQu9HuOVYDtJ9UdZOO YtEQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1789184918; x=1789789718; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=5SE/qOas+/SI2EvNxtEJVx4SSxOPMNxV+dkdmLC2H+E=; b=L0oOyMxNZi+RfVPCTgRAq6d+VYY5xQiVbTf2oPz1EK4KrQ8E2BYYg4vT8ozufz65Gq 1tjs18kpuuX9l9ixFaweZ+GLhr/HOdEwMyc8nrwm4TkDs959TwSonHHxjPDTlj1pRInK pl+PaseobQBmUwBU6cSVsT22OS2Sf2fKKdpn2wkvP17vmkLQoqkKWYYtN+Z8QC97xt43 w8bOhqa7857g5TIq8lMzToEVY4pxtuVobZnFBJDuAk0/eZluTuDZ8CwjG4InXObOkucq kW9O5cDfXGMiwTDS9k5Pm/MMxeM1KFJVi+aympujrc+27nyzTDK2ChsqKBfXnGDZuiF/ duoA== X-Gm-Message-State: AFuF++npNx1/Y2NgX+bjFOg4EchsT6kzLZISTRqWA+buBxNiJ51dMf41 EyA8I8BgnQtfQiAiNJB8/mzkphcISQ18FNwBPtNb+XfvOZSa88G9ewKoXI0vV5cksjQ= X-Gm-Gg: AYBFou1pWUDFtWbuc3qXDyhJjGSXVywUNGz5OmtoUIvv0fVAOdjV2avmJ3SXGw59YiY NzhIV+kWwURdFto/SMT9rL32tps3N9Qxa3k23eqPIRAmYhggZDxQ7NZFMO6kcOl4vW/H5GsTZrS EnyyArrq3+Zj7Q0dIkQIo9o7TXr+QZF1+kX/IqvqijpaZiRpjqX/vP0aL9ruW55+0Mm/iwGsa8b 6jbc1pBNRphykz2b1Dot8J85u+2AP4WcgdEZbH0/QXCjsJ9iJN8TtPNu0v8+xpTFsi5qi13sNQw rUAJx0/2cidk/QRAuEjn+iuG7GdaMyMyDbrgXzkrMcu6dg5a0Ar+Zlx4g6agK8bSajUHoQzxePu N/ctPT/I2C1cwoQ7SzOp0AqbFCp3jFH2VusSfO5/fj+oY8uQlj+b0hIr90B4Den+NLWt9rmYUhZ JPT/feBcEZ8nBsjhnpTvUo59c0qNRKm7Kk8wk/mLw2gy28/dM1v1Bb0uQ4m0an073Xfsxf4kq9H TktylPhtaNEqFIShxcmOQZZu6kFA83BtwGBT88zCkS/6sChwn4G6qP4eUjz X-Received: by 2002:a05:6214:29ef:b0:912:289:647f with SMTP id 6a1803df08f44-912121145f1mr108338996d6.33.1789184918116; Fri, 11 Sep 2026 20:48:38 -0700 (PDT) Received: from gourry-fedora-PF4VCD3F.lan (pool-173-79-60-52.washdc.fios.verizon.net. [173.79.60.52]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-9120f494620sm36252476d6.28.2026.09.11.20.48.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 11 Sep 2026 20:48:37 -0700 (PDT) From: Gregory Price To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, akpm@linux-foundation.org, liam@infradead.org, ljs@kernel.org, david@kernel.org, vbabka@kernel.org, jannh@google.com, ziy@nvidia.com, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, gourry@gourry.net, ying.huang@linux.alibaba.com, apopple@nvidia.com, peterx@redhat.com, jgg@ziepe.ca, sashiko-bot , stable@vger.kernel.org Subject: [PATCH v2 1/2] mm/mempolicy: use vm_normal_folio_pmd() in queue_folios_pmd() Date: Fri, 11 Sep 2026 23:48:32 -0400 Message-ID: <20260912034833.2952750-2-gourry@gourry.net> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912034833.2952750-1-gourry@gourry.net> References: <20260912034833.2952750-1-gourry@gourry.net> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit mmap a VM_PFNMAP region whose ->huge_fault installs a PMD through vmf_insert_pfn_pmd() - a vfio-pci MMIO BAR does this - then mbind(p, len, MPOL_BIND, &mask, maxnode, MPOL_MF_STRICT); With a stand-in module for the driver: BUG: unable to handle page fault for address: fffff96dc0000008 RIP: 0010:queue_folios_pte_range+0xaf/0x440 walk_pgd_range+0x52b/0xaf0 __walk_page_range+0x6a/0x1d0 walk_page_range_mm_unsafe+0x193/0x230 queue_pages_range+0x64/0xa0 do_mbind+0x25e/0x640 queue_folios_pmd(), inlined above, calls pmd_folio() on that PMD. The pfn is raw MMIO with no memmap entry, so the folio lands in unpopulated vmemmap. Neither guard stops the walk: walk_page_test() skips VM_PFNMAP, but queue_pages_walk_ops supplies ->test_walk, so it never runs queue_pages_test_walk() honours vma_migratable(), but only while MPOL_MF_STRICT is clear A VM_MIXEDMAP vma needs neither flag, being vma_migratable(), so plain mbind(MPOL_MF_MOVE) reaches this too - and there the bad folio carries on into migrate_folio_add() and folio_isolate_lru(). mshv_vtl_low is such a mapping. Use vm_normal_folio_pmd() and skip on NULL, as the PTE loop in queue_folios_pte_range() already does with vm_normal_folio(). On the NULL path, retain ACTION_CONTINUE handling for the huge zero PMD. mbind(MPOL_MF_STRICT) over a PMD mapped VM_PFNMAP region now returns 0 rather than -EIO. The PTE loop already returned 0 there. Fixes: 3c8e44c9b369 ("mm: mark special bits for huge pfn mappings when inject") Reported-by: sashiko-bot Closes: https://sashiko.dev/#/patchset/20260817220810.1175596-1-gourry%40gourry.net Cc: stable@vger.kernel.org Assisted-by: LLM Signed-off-by: Gregory Price (Meta) Acked-by: David Hildenbrand (Arm) --- mm/mempolicy.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 2ad0a5f18280..8fc8a975657e 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -667,7 +667,8 @@ static inline bool queue_folio_required(struct folio *folio, return node_isset(nid, *qp->nmask) == !(flags & MPOL_MF_INVERT); } -static void queue_folios_pmd(pmd_t *pmd, struct mm_walk *walk) +static void queue_folios_pmd(pmd_t *pmd, unsigned long addr, + struct mm_walk *walk) { struct folio *folio; struct queue_pages *qp = walk->private; @@ -678,13 +679,14 @@ static void queue_folios_pmd(pmd_t *pmd, struct mm_walk *walk) qp->nr_failed++; return; } - folio = pmd_folio(pmdval); - if (folio_is_zone_device(folio)) - return; - if (is_huge_zero_folio(folio)) { - walk->action = ACTION_CONTINUE; + folio = vm_normal_folio_pmd(walk->vma, addr, pmdval); + if (!folio) { + if (is_huge_zero_pmd(pmdval)) + walk->action = ACTION_CONTINUE; return; } + if (folio_is_zone_device(folio)) + return; if (!queue_folio_required(folio, qp)) return; if (!(qp->flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) || @@ -717,7 +719,7 @@ static int queue_folios_pte_range(pmd_t *pmd, unsigned long addr, ptl = pmd_trans_huge_lock(pmd, vma); if (ptl) { - queue_folios_pmd(pmd, walk); + queue_folios_pmd(pmd, addr, walk); spin_unlock(ptl); goto out; } -- 2.55.0