From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f74.google.com (mail-wm1-f74.google.com [209.85.128.74]) (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 D7B713E51E8 for ; Wed, 3 Jun 2026 16:11:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780503086; cv=none; b=gZxb0g6yMy6UGaKo1fROHGIEXWwomSkxywMtRQ7TzlnZyGfbZSPdwf38lnf9aWhnvyLbUT1GgYoZvRgc5WVRx17He0jMIlaceuM5qljsMNZ1SwM8lhBZ28IaJjgx5X7gaYJ5r3s9lm6MrvMFuhaoD0pHQ7mLUwj5ddfDrU2lRus= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780503086; c=relaxed/simple; bh=Sxq8KhfQah2sz1OaM1MlEZAstsAQ3MB/PdaH812A9kI=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=MzHQwnX4BZJ8N4TOxJcWvrBGwMOvYFqlI545GjRSfkp0ybwkFxd10Gbqa1ULWlsrctSpRVGCA8vgaXmwB1R5gbhq3KQ9YWFlGuu6A4wKppctMWcfWT9Cs+9CIoH+vkxWrO02agk9cx2XKStkCFzngJdBbL4gFUNcozvOAg2zOTs= 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=FLy6AbVM; arc=none smtp.client-ip=209.85.128.74 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="FLy6AbVM" Received: by mail-wm1-f74.google.com with SMTP id 5b1f17b1804b1-4904ee02e72so99911445e9.1 for ; Wed, 03 Jun 2026 09:11:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1780503083; x=1781107883; 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=oimI3tmTeudUzVEIRzgp5TsbqR86loAKNzvaAFIXh5A=; b=FLy6AbVMAU8lWVNtevG8xlCK+eTTZDshLekmcC/KNLxZZfYieqyuXbVS1Z7+7fOxeB h2qa7XkoOgvdH0ed59SCHuSm0RoSM2VUHl37x4teeAoHWN2jnOSspluJ/DO+aDvPxNxt m7LkyplNsdb+XrgeRDVTtCZc/lBgV2zCgUs72zFGelYUYXk0EJEeXQ5g0PTrnlYNfL0W H6nPrBueVrOyDvQk8bx3xiapRsB/rwiTumEaKV6TqFr/eED2oDFx8G8P+rYJG3s7ZKY/ 4wF1SBmBu3WQ/04PTGEtkA/OTebhQj2kZ4z51SAG1bfvtHQ/eZ6S0nKAQ5Kxmqss7Gn6 lBRA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1780503083; x=1781107883; 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=oimI3tmTeudUzVEIRzgp5TsbqR86loAKNzvaAFIXh5A=; b=X7c4IynXZQf9nVBLJk3zzoydACcp3pq8eG7pFUGrOZGdbY1z/XQRXDVH1EvV/68MOZ CgcOvaWqj7xXeWMCxFchLpoD9iHQn1UmR024/3wubbMERr72Xjk01Ch0evzlfFs6V0Vv XqfOcauDJ0qGKXIrP2xNwDnSTRVNeZK2FsLM4y7eZ3VuxI25aMZxCQUsHkw8yR+RyZ4A o9B5yPPhsVJh3zbAjRFe48dJSEbjuQQFCnUxirCA0XsX7sg5uV4HaJLZPiR240SP8938 Zq89bTR5APzXo0qevtNJWKae/IyZs0Fd2ywz8FFVQzPH/hSGY1bBm7TFB20wE3/w/ldE F/Xg== X-Gm-Message-State: AOJu0YyasyHH36rsCWbzEWBApQO10i3bsEoOFBu1ZcNJKnitO+8YIIn5 IHQ/UJ9yVYYaTknVQwkVjYtvW53OLtsb8F3SzkmIWa7kb+ogneQuuG33MtYn2Kr36Ufv72xB7w= = X-Received: from wmpy16.prod.google.com ([2002:a05:600c:3410:b0:490:ac8b:3a74]) (user=ardb job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:3b09:b0:490:b475:af32 with SMTP id 5b1f17b1804b1-490b5e5da1amr70363605e9.23.1780503083096; Wed, 03 Jun 2026 09:11:23 -0700 (PDT) Date: Wed, 3 Jun 2026 18:09:54 +0200 In-Reply-To: <20260603160949.3372482-6-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: <20260603160949.3372482-6-ardb+git@google.com> X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 X-Developer-Signature: v=1; a=openpgp-sha256; l=2090; i=ardb@kernel.org; h=from:subject; bh=kKVLW1q4ohISCLzJXLX0SgEDWExD4Na9wQ8ubZPYl8I=; b=owGbwMvMwCVmkMcZplerG8N4Wi2JIUsh8Mofu9i66rN/dCOM8tobT3uXTsizYVojeUT/yoE4j ainrLIdpSwMYlwMsmKKLAKz/77beXqiVK3zLFmYOaxMIEMYuDgFYCJ7XzP8M/gj2uC0dkLiVZeP rrlLLOYbiD5v1l/KN+3Svtr9jP+vvmdkWCXPzaSt1VYk1WmqKr5xw5Tnq5nE3OJeKPcssJr9jzG AAwA= X-Mailer: git-send-email 2.54.0.1013.g208068f2d8-goog Message-ID: <20260603160949.3372482-10-ardb+git@google.com> Subject: [PATCH 4/4] 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, maz@kernel.org, Ard Biesheuvel , Kevin Brodsky , Mark Brown 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. 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) -- 2.54.0.1013.g208068f2d8-goog