From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C93D233F58B; Tue, 15 Sep 2026 06:32:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789453979; cv=none; b=m9OlrjpteEL16OfBxCFGJ02laXXPWpILtN9eF/knwlXulTGLu3EJZ/O02a5iHxczpsDNTiRwgkoObaXXZoN+ubcIAk5jz3n7GbPfjurP7kHV8nykChOw3m9Kv/lwFFRLIQbiTs1yH54T+dLspltTNJP44gcz7WlyUbuvqF5+kaA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789453979; c=relaxed/simple; bh=XDIBKee2ih47Hhh2OCaF3AJfh9RssxjIG0IQIj/aXLo=; h=Date:To:From:Subject:Message-Id; b=p4lB19/TNdFLibC1JZcC+yOs4hCrm5OEZQg/PCVueei81Jn07ei3y7eUQJVTfG4SujcGQvvkfLS623lgvzQT6qBLtiX0Im+3NHLptmCRKMEnvhsdx407Plw12aFeh3LSnQimGRkz7SkPUgoCsjoT5ZOPduvl5oO2gVOAQqOR0KM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=eztsVct8; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="eztsVct8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4497B1F000FF; Tue, 15 Sep 2026 06:32:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1789453977; bh=mXLIxQYlw9AGMjpu/G7Y9Z00Vlod80mQCMF6/5pW8cc=; h=Date:To:From:Subject; b=eztsVct8/1G/7jsZHxbmUD87WMqaJJGTympHdpzQfuv9mJJ7Hb29USTvRR7n7FQ+z UTfKipsrNe40fPaWIrNlN36WLra/kA/r4ftXqO3ney6goNx+9T2z9A16cv361O2iUK jGf8KiijjqbH/QZJbshJWbFWYG5ermJJw/sM1Ruk= Date: Mon, 14 Sep 2026 23:32:56 -0700 To: mm-commits@vger.kernel.org,wangjiexun@tinylab.org,vbabka@kernel.org,stable@vger.kernel.org,sashiko-bot@kernel.org,ljs@kernel.org,liam@infradead.org,jannh@google.com,david@kernel.org,gourry@gourry.net,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-madvise-reclaim-isolated-folios-if-pte-restart-fails.patch added to mm-new branch Message-Id: <20260915063257.4497B1F000FF@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm/madvise: reclaim isolated folios if PTE restart fails has been added to the -mm mm-new branch. Its filename is mm-madvise-reclaim-isolated-folios-if-pte-restart-fails.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-madvise-reclaim-isolated-folios-if-pte-restart-fails.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. The mm-new branch of mm.git is not included in linux-next If a few days of testing in mm-new is successful, the patch will me moved into mm.git's mm-unstable branch, which is included in linux-next Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Gregory Price Subject: mm/madvise: reclaim isolated folios if PTE restart fails Date: Sat, 12 Sep 2026 07:08:32 -0400 MADV_PAGEOUT collects isolated folios on a local list before reclaiming them after the PTE walk. The reschedule path drops the PTE lock and then restarts the mapping with pte_offset_map_lock(). A concurrent operation can remove or replace the PTE table while the lock is dropped, causing pte_offset_map_lock() to return NULL. Returning directly in that case bypasses reclaim_pages(), leaving the collected folios off the LRU with elevated references. Route the failure through the existing cleanup path so any isolated folios are reclaimed or put back. Simplest userland pseudo-code reproducer: p = mmap(PMD_SIZE, ANONYMOUS); touch_every_page(p, PMD_SIZE); parallel { while (1) madvise(p, PMD_SIZE, MADV_PAGEOUT); while (1) { madvise(p, PMD_SIZE, MADV_DONTNEED); touch_every_page(p, PMD_SIZE); } } Reproduced in qemu trivially with some explicit widening of the race window. Link: https://lore.kernel.org/20260912110832.3203902-1-gourry@gourry.net Fixes: b2f557a21bc8 ("mm/madvise: add cond_resched() in madvise_cold_or_pageout_pte_range()") Signed-off-by: Gregory Price (Meta) Signed-off-by: Andrew Morton Reported-by: sashiko-bot Closes: https://sashiko.dev/#/patchset/20260821150912.183976-1-gourry@gourry.net Assisted-by: LLM Cc: David Hildenbrand Cc: Jann Horn Cc: Jiexun Wang Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Vlastimil Babka Cc: --- mm/madvise.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/mm/madvise.c~mm-madvise-reclaim-isolated-folios-if-pte-restart-fails +++ a/mm/madvise.c @@ -463,7 +463,7 @@ regular_folio: restart: start_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); if (!start_pte) - return 0; + goto out; flush_tlb_batched_pending(mm); lazy_mmu_mode_enable(); for (; addr < end; pte += nr, addr += nr * PAGE_SIZE) { @@ -567,6 +567,7 @@ restart: folio_deactivate(folio); } +out: if (start_pte) { lazy_mmu_mode_disable(); pte_unmap_unlock(start_pte, ptl); _ Patches currently in -mm which might be from gourry@gourry.net are mm-mempolicy-take-a-cpuset-cookie-for-the-interleave-node-count.patch mm-mempolicy-use-srcu-for-the-weighted-interleave-state.patch mm-mempolicy-stop-copying-the-nodemask-in-the-interleave-paths.patch mm-huge_memory-skip-zone-device-folios-in-madvise_free_huge_pmd.patch mm-madvise-skip-zone-device-folios-in-cold-pageout-pmd-range.patch mm-mempolicy-skip-zone-device-folios-when-queueing-folios.patch mm-memory_hotplug-factor-out-node_is_memoryless.patch mm-mempolicy-use-vm_normal_folio_pmd-in-queue_folios_pmd.patch mm-madvise-use-vm_normal_folio_pmd-in-cold-pageout-pmd-range.patch mm-refactor-find_next_best_node-to-find_next_best_node_in.patch mm-page_alloc-refactor-build_node_zonelist-out-of-build_zonelists.patch proc-task_mmu-handle-special-pmds-in-clear_refs-and-pagemap.patch mm-madvise-reclaim-isolated-folios-if-pte-restart-fails.patch