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Tue, 03 Nov 2026 10:33:02 -0800 (PST) Received: from localhost ([2605:8600:200:14e3:365a:60ff:fe62:ff29]) by smtp.gmail.com with ESMTPSA id 00721157ae682-8b30997aa84sm2416257b3.29.2026.11.03.10.33.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Nov 2026 10:33:01 -0800 (PST) Date: Tue, 3 Nov 2026 13:33:00 -0500 From: Johannes Weiner To: "Vlastimil Babka (SUSE)" Cc: "Gregory Price (Meta)" , Zi Yan , Shakeel Butt , Mike Rapoport , David Hildenbrand , Oscar Salvador , "Matthew Wilcox (Oracle)" , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Josef Bacik Subject: Re: [PATCH v2 3/5] mm: page_isolation: do not take slab pages for free Message-ID: References: <20261103-pgalloc-ai-hotfixes-v2-0-e0d2890ab74f@kernel.org> <20261103-pgalloc-ai-hotfixes-v2-3-e0d2890ab74f@kernel.org> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261103-pgalloc-ai-hotfixes-v2-3-e0d2890ab74f@kernel.org> On Tue, Nov 03, 2026 at 05:16:49PM +0100, Vlastimil Babka (SUSE) wrote: > From: Josef Bacik > > 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"). > > Fixes: 9aec2fb0fd5e ("slab: allocate frozen pages") > Assisted-by: LLM > Signed-off-by: Josef Bacik > Signed-off-by: David Hildenbrand (Arm) > Reviewed-by: Zi Yan > Signed-off-by: Vlastimil Babka (SUSE) Reviewed-by: Johannes Weiner