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 523873515D2; Fri, 4 Sep 2026 05:07:33 +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=1788498454; cv=none; b=XQCQavzhl2sJmDeB90o5gRWwElxRNdYuT8jwdTvKu77INm+xtO0kRXdffv7BPYipP0DQd7tbqVEv/5T/1gxWylJvHO3NiBu/Ww9cj91awLjn3sY99DIdZ88RlHBnbMxlqJA5eP+TMrNVFBpVaF++lhN5xYFwm+JFKhcJqb6Un5c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788498454; c=relaxed/simple; bh=EhRTyIZGQyBOwzaB6ENafVq3nIAQqRGuojacgjnphQ4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=u8E8xQ0F/aWE8TylSrkGlhWQgcuApUWg7h39LAg++VsjcrIYeVLOxkNkK/YU9lbXBj0s8O3oWX8xhoHRoPRrwcsaV1SdH7IT++bOPqLv534wkAp5gC8bHjz53WDzu4kZurKQQLXZPi4DnOROpvdvqds/YWDIVbJv/GQF6O3sfZw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=i1FEx9N6; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="i1FEx9N6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AB6711F00A3D; Fri, 4 Sep 2026 05:07:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788498453; bh=ISMQSZXVhAUPmAc9GBrzxmyNqYRYjt/908HmhpTJU4w=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=i1FEx9N6Pm+HjUXV1lfQBsqZxvPVRT3Q/rnA3mzK7MUBAEzEpmYRO8gXl+IVBCUbp AQG2oEHXoONqV/OCJM7Wg+rtMlDewAsS6JnU6Nx6CK4Hf3ha4A3xxipabufCbxr1OY K3hJx3m2k+fo/pw/9OK0UwMz5/mh6J1Zu/K9h+0g= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Shengming Hu , "Harry Yoo (Oracle)" , Hao Li , "Vlastimil Babka (SUSE)" Subject: [PATCH 7.2 067/713] mm/slub: prevent pfmemalloc objects from entering the barn Date: Fri, 4 Sep 2026 06:50:35 +0200 Message-ID: <20260904045805.343814706@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045803.810145556@linuxfoundation.org> References: <20260904045803.810145556@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Shengming Hu commit 9338b189be6895e45cf6fcf819c55cd3c47e4a18 upstream. kmem_cache_return_sheaf() may refill a partially consumed sheaf before placing it in the barn. Without an explicit restriction, this refill may draw objects from pfmemalloc slabs and consume emergency reserves. Add __GFP_NOMEMALLOC so that returned sheaves are refilled only from non-pfmemalloc slabs. Also add __GFP_NOWARN, as suggested by Hao Li, because this refill is a best-effort attempt and failure is acceptable. If the refill fails, flush and free the sheaf instead. Fixes: 1ce20c28eafd ("slab: handle pfmemalloc slabs properly with sheaves") Cc: stable@vger.kernel.org Signed-off-by: Shengming Hu Reviewed-by: Harry Yoo (Oracle) Reviewed-by: Hao Li Link: https://patch.msgid.link/20260721084522552ZPa16p1SRj3PYat3sqxuN@zte.com.cn Signed-off-by: Vlastimil Babka (SUSE) Signed-off-by: Greg Kroah-Hartman --- mm/slub.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/slub.c +++ b/mm/slub.c @@ -5153,7 +5153,7 @@ void kmem_cache_return_sheaf(struct kmem * simply flush and free it. */ if (!barn || data_race(barn->nr_full) >= MAX_FULL_SHEAVES || - refill_sheaf(s, sheaf, gfp)) { + refill_sheaf(s, sheaf, gfp | __GFP_NOMEMALLOC | __GFP_NOWARN)) { sheaf_flush_unused(s, sheaf); free_empty_sheaf(s, sheaf); return;