From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f73.google.com (mail-wr1-f73.google.com [209.85.221.73]) (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 E0F46348C73 for ; Thu, 4 Jun 2026 15:12:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780585946; cv=none; b=bBGuExWSaDNVaRVBaQNCejm3ORG38AaAoDvD9rrjWhEpqtToB13Rl2zklI5YsbkKW3ysl3tJMYswFT9g9aofQlWZHKcm2l7NC1VLJknpcYAG1vFuBUTQ4V+xBCMPlzr6oSHtzK4nLxxIyJyICu4PVSXDcfqEaiFbjAYwXXWKZ0g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780585946; c=relaxed/simple; bh=RjabiXVJbyjDFF8QC9c1zqzpI6ZmnO2wM1vU3yWxGuw=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=TjksQ0oThrHmpZqQY8GRUZ26q0hkKpGnZt/Voxn1AzuGyMZidx7Bznag6CmGlIX1+c7v/EV7KyvkINgMXASyWdpCvqQQPQA7x/LM7M/eiIs1yiRMb+WoHyF/lmAojj/V+UJ4JjlGf/M3lLt31Nx+Hy8Oavmvh31nNaUMw1ONfrQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--ardb.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=gISs2rye; arc=none smtp.client-ip=209.85.221.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--ardb.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="gISs2rye" Received: by mail-wr1-f73.google.com with SMTP id ffacd0b85a97d-4601daf4c65so527811f8f.2 for ; Thu, 04 Jun 2026 08:12:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1780585943; x=1781190743; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=vn2prO5o05wItrpzO+IXrwTtuowQn2HpWBal1Vxejcc=; b=gISs2ryeetGNOi2cfqLC2EQU6q4Cdt261s3wNX6hhyKP26NFEETTbfjDaBLwAfdKtr ydOQ6Sz3jBM0HpM+77OaYaGfk7YZq0tMVYHIvQDcXSlSuq+uTMRjpERu8NxpzG50efVD GdcHnkfqCBOHE3Jc21PvhYXmVywl8eBxu1Q/kWW7lGHOT19U401VNNZ7pPk5FzULZbZA rGfBpblhYJojE9m6mslp3cIejgHj8E1Hg/8TgJ2dTQtovd13KiJHzACvB+WhPxTZQfpy iP/zAItzQW52TrSoSoXCXRwO9/Ok6ke1nkR/2RTxUuQF4I/WCz6T0K5LfgdNtlH68B07 z1cQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1780585943; x=1781190743; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=vn2prO5o05wItrpzO+IXrwTtuowQn2HpWBal1Vxejcc=; b=b4sMfrGWN/hbFo90Fo06DaoXQ9kZK5Sw6H3o8WOM5vgjoyIe6azE5nL2z7ni9h23w8 W++bdBOLT+NzwaflLig9rM8o18Bn2r21Mb9/X1iVxN80IL1xPjXY6F3TxEKpiUh5vs5Q KoEHwBjbBxhqs9guX36Hmm9pKyCzdtDlBRspvoHKMipBYTaxj4AXEmmVMZcODg9vNSlj jqytnxHP2QBb6qAIBbIoP2H965mfImY4pUe8v0bFPsmGVl8ZoFSnmgJruFOKRuiu1FMJ xiRxpPPvFUTPJPnrWCOY8KPw1qFhwgETGgIlQXhtwbOzzdrbcz2gxW3XjNwBvK//sM7H Wh2Q== X-Gm-Message-State: AOJu0YxarsLDaO3U45JwjXwHQ2L7hX2Eid5k8umX7E4v5aYr81VTOEPV QY7z0B1IjLHHurx5WoTQ0pBlZnWXJ6hg7TaH0e6sirMRYBxwh/LgV6pd2y/bJggo21lIQZxUFA= = X-Received: from wmd16.prod.google.com ([2002:a05:600c:6050:b0:490:b32e:ef70]) (user=ardb job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:1f96:b0:490:53d3:47a9 with SMTP id 5b1f17b1804b1-490b5e7962dmr132211665e9.3.1780585942997; Thu, 04 Jun 2026 08:12:22 -0700 (PDT) Date: Thu, 4 Jun 2026 17:11:57 +0200 In-Reply-To: <20260604151151.150377-7-ardb+git@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260604151151.150377-7-ardb+git@google.com> X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 X-Developer-Signature: v=1; a=openpgp-sha256; l=2216; i=ardb@kernel.org; h=from:subject; bh=kV5OmQpXjgFAS7tCAScTDlrNCgx2UTozsq6mIJLDLaw=; b=owGbwMvMwCVmkMcZplerG8N4Wi2JIUtx6oHaU/ozd+7jFmBSUJq87skO7VmvdH5vr4uzO/6a/ /8qmZMZHaUsDGJcDLJiiiwCs/++23l6olSt8yxZmDmsTCBDGLg4BWAiN04w/M+bulX5sH7iIYlv m9auPOww+5Ogbav4KsNWhoy7ydPPZ7cx/DMNen1ptYP/+hXK7y+dj7zCqlgRIvO9IfjDscc8ne8 UWhgB X-Mailer: git-send-email 2.54.0.1032.g2f8565e1d1-goog Message-ID: <20260604151151.150377-12-ardb+git@google.com> Subject: [PATCH v2 5/5] arm64: mm: Defer remap of linear alias of data/bss From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, will@kernel.org, catalin.marinas@arm.com, Ard Biesheuvel , Kevin Brodsky , Mark Brown , Marc Zyngier Content-Type: text/plain; charset="UTF-8" From: Ard Biesheuvel Marking the linear alias of data/bss invalid involves calling set_memory_valid(), which calls split_kernel_leaf_mapping() under the hood. On BBML2_NOABORT capable systems, this may result in the need to allocate page tables at a time when the generic memory allocation APIs are not yet available, resulting in a splat like WARNING: arch/arm64/mm/mmu.c:821 at split_kernel_leaf_mapping+0x15c/0x170, CPU#0: swapper/0 Modules linked in: CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 7.1.0-rc6 #1 PREEMPT(undef) pstate: a04000c9 (NzCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : split_kernel_leaf_mapping+0x15c/0x170 lr : update_range_prot+0x40/0x128 sp : ffffc99ad3863c80 ... Call trace: split_kernel_leaf_mapping+0x15c/0x170 (P) update_range_prot+0x40/0x128 set_memory_valid+0x94/0xe0 mark_linear_data_alias_valid+0x54/0x68 map_mem+0x1fc/0x240 paging_init+0x48/0x210 setup_arch+0x274/0x338 start_kernel+0x98/0x538 __primary_switched+0x88/0x98 as reported by CKI automated testing. So defer the boot-time call to mark_linear_data_alias_valid() to a later time when page allocations can be made normally. Signed-off-by: Ard Biesheuvel --- arch/arm64/mm/mmu.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index d68e691c093a..3134f1c1097c 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1095,6 +1095,9 @@ void __init mark_linear_text_alias_ro(void) (unsigned long)__init_begin - (unsigned long)_text, PAGE_KERNEL_RO); + /* Map the kernel data/bss as invalid in the linear map */ + mark_linear_data_alias_valid(false); + /* * Register a PM notifier to remap the linear alias of data/bss as * valid read-only before hibernation. This is needed because the @@ -1237,9 +1240,6 @@ static void __init map_mem(void) __map_memblock(start, end, pgprot_tagged(PAGE_KERNEL), flags); } - - /* Map the kernel data/bss as invalid in the linear map */ - mark_linear_data_alias_valid(false); } void mark_rodata_ro(void) -- 2.54.0.1032.g2f8565e1d1-goog