From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793131541; b=RVBaIcDvLg0wNRp39Ek5sWu6JkjlhIlHDmVpdXCQ+95i7pCzh9GrM4hHrG6ddhAbM+xv gblDJWoIVzaouucBY+3zkIc5m7IIpbmVIzq+qEldDoMCcTf1iJougwaNqalg7YOSpuDGJ qy2wof8/DtVeTtKT9ZMo7/kjZoeaUKH3QSxtpo3TxNl8OW461CjB2fmggEONYDyALWpxO 0+79Z7+lACs824Qxt7Yl2UR3Flt2mfcH4zqWKMLTd4nCbsJrQSRRkTup9rtEiN995W1mq tNJRP+XJzGQpJbIgutdcU0OY/dYO074cpoF1hA3KHMXNwxOwbXgf82aHiDcCnE8Ccrw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793131541; h=Received:DKIM-Signature:Date:To:From:Subject:Message-Id; bh=Ni6rZXDKUU/HVbAcRThSmr5VLY6OruNGAORYRyf55LA=; b=1Q0tk4F/fTiRJujXA3usTt9o3saKOJlCmRp2uM6W5jiDVg47UXaSl0akGLiYx47Rgp6Z 8YUu7kTl6WgCg45Vr/5QFmkLNHR1F7W2jzYqbk8CcH82OmTKtf1lF4GxkeQBEzf+2I+MC tELmYtixdt6R9rKS0oOLHrjn8NvWQcDtu0qKw7L/KOUfSyq05CTDOD2lh2x4zc1AkbyMJ hhrR3QelTxj/BLgvv2XD4lTXjOgH98+js9SnDUWr5MeNVY8+G/49icyJUGf5pG5B/LDnl 6N0wxinWOkYIJVvqlP7kItRi1uUgQHEE6VG6k7BkDr7tga1fKPzWQngj9MPfOlWzu0A== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=fePsXDbH; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 59B12606A31A for ; Tue, 27 Oct 2026 20:05:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=fePsXDbH Received: by smtp.kernel.org (Postfix) with ESMTPSA id DBD4E1F01825; Tue, 27 Oct 2026 20:05:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1793131541; bh=Ni6rZXDKUU/HVbAcRThSmr5VLY6OruNGAORYRyf55LA=; h=Date:To:From:Subject; b=fePsXDbHsxLETceThFTt2hLTk3rTZqDhIqUhp+nH1sW/k/xr0QYg8R3v+DVhHOIRp RCiiRiyTAVqJejMRW22ialkTScjf1eXfGlVeeVPnM4e+Ofov4my7eFq9/8uuO3ymZO cvzz7VJHD+ZDvFZ10/tZA+rIHIdc+e1XXGhL+sCs= Date: Tue, 27 Oct 2026 13:05:40 -0700 To: mm-commits@vger.kernel.org,ziy@nvidia.com,willy@infradead.org, vbabka@kernel.org,surenb@google.com,shakeel.butt@linux.dev,rppt@kernel.org, osalvador@suse.de,mhocko@suse.com,hannes@cmpxchg.org,gourry@gourry.net, david@kernel.org,brendan.jackman@linux.dev,josef@toxicpanda.com, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-page_isolation-do-not-take-slab-pages-for-free.patch added to mm-unstable branch Message-Id: <20261027200540.DBD4E1F01825@smtp.kernel.org> X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list The patch titled Subject: mm: page_isolation: do not take slab pages for free has been added to the -mm mm-unstable branch. Its filename is mm-page_isolation-do-not-take-slab-pages-for-free.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-page_isolation-do-not-take-slab-pages-for-free.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm 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: Josef Bacik Subject: mm: page_isolation: do not take slab pages for free Date: Tue, 27 Oct 2026 16:46:33 +0100 page_is_unmovable() regards a page with a reference count of zero as free or about to be freed. Since slab allocates frozen pages, they will be wrongly considered to be freed if order 0 (higher-order compound pages are caught earlier). If such slabs are the only unmovable pages of a memory block, memory offlining now isolates the block, this can lead to offline_pages() looping without progress. Thus detect the slab pages as removable to return -EBUSY, as would happen before commit 9aec2fb0fd5e ("slab: allocate frozen pages"). Link: https://lore.kernel.org/20261027-pgalloc-ai-hotfixes-v1-7-9c7d1aca801e@kernel.org Fixes: 9aec2fb0fd5e ("slab: allocate frozen pages") Signed-off-by: Josef Bacik Signed-off-by: Vlastimil Babka (SUSE) Signed-off-by: David Hildenbrand (Arm) Signed-off-by: Andrew Morton Assisted-by: LLM Cc: Zi Yan Cc: Shakeel Butt Cc: Mike Rapoport Cc: Oscar Salvador Cc: Matthew Wilcox (Oracle) Cc: Suren Baghdasaryan Cc: Michal Hocko Cc: Brendan Jackman Cc: Johannes Weiner Cc: "Gregory Price (Meta)" --- mm/memory_hotplug.c | 7 +++++++ mm/page_isolation.c | 7 +++++++ 2 files changed, 14 insertions(+) --- a/mm/memory_hotplug.c~mm-page_isolation-do-not-take-slab-pages-for-free +++ a/mm/memory_hotplug.c @@ -1847,6 +1847,13 @@ static int scan_movable_pages(unsigned l if (PageOffline(page) && page_count(page)) return -EBUSY; + /* + * A page that was allocated, but was not a slab page yet, when + * its pageblock was isolated. + */ + if (PageSlab(page)) + return -EBUSY; + folio = page_folio(page); if (!folio_test_hugetlb(folio)) continue; --- a/mm/page_isolation.c~mm-page_isolation-do-not-take-slab-pages-for-free +++ a/mm/page_isolation.c @@ -75,6 +75,13 @@ bool page_is_unmovable(struct zone *zone } /* + * Slab pages are frozen: do not take their reference count of zero + * for that of a free page. + */ + if (PageSlab(page)) + return true; + + /* * We can't use page_count without pin a page * because another CPU can free compound page. * This check already skips compound tails of THP _ Patches currently in -mm which might be from josef@toxicpanda.com are mm-page_alloc-dont-undo-a-racing-start_isolate_page_range.patch mm-page_alloc-clear-private-of-deferred-free-pages.patch mm-page_frag-refill-the-cache-for-large-fragments.patch mm-page_alloc-keep-the-pagesets-of-an-empty-zone.patch mm-page_alloc-pass-zone-pointer-to-trace_reclaim_retry_zone.patch mm-compaction-trust-zone-contiguous-only-in-the-span.patch mm-page_isolation-do-not-take-slab-pages-for-free.patch mm-memory_hotplug-resize-zones-under-their-seqlock.patch mm-page_alloc-check-pageblock-pfns-under-span-seqlock.patch