From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f169.google.com (mail-pf1-f169.google.com [209.85.210.169]) (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 ED2BE37F8C6 for ; Fri, 1 May 2026 23:45:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.169 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777679111; cv=none; b=hbKFhNLgQEFwW6DObq/vzrzES/D46vH+B1pU3cOIpfO6704LPk+2gn5SFCCDHVJSIVaulgJH1W0Y9YLVWIJkFX/0/DaxPjmJ1Je7dE/ho2PIQpSqlhOBc6hNUxyaYJILL2w2aUrNfn0A0+1BfViUKnnskTufithdde6v97Ygxm0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777679111; c=relaxed/simple; bh=jEByxMe9snhkQrbdmllNh1T51Z1nkOiwKTUY+XOqkqY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=H7/gn962uSxJyVDiAWSUc/V/Q9JyZrtccG8jwc5rpJu0HmdTCWScmx4DsqnC4ETNLY+17JNfQxuVmQFG3BVZwHPpKjmwFdnL7Z3SNGuQtkykxu1pbgW8TaJpptERK04Wj8/T7gmzRv33Upbf71nvEbQJOh7M2vmGQ0qj4+lePp4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=hlkcMAA0; arc=none smtp.client-ip=209.85.210.169 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="hlkcMAA0" Received: by mail-pf1-f169.google.com with SMTP id d2e1a72fcca58-8296d553142so1559744b3a.3 for ; Fri, 01 May 2026 16:45:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1777679108; x=1778283908; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=x3HMy/5x+GTu/U/2MxeUBt4BoOwWC+Ga4gJ09h6qLJI=; b=hlkcMAA0ezh7QSvGT1oZCBbswKyuJI+QHIjybjRW2IU3YBusmHhkT1IyaKDiOug1AB i43SYqrr4j4waPmXkLZwjPpZCZ0dnE95s+N3EFr2tUkC041niW+j5ayL9mops3lLnMEq eWs7bM0YsZO/EiF+8Jr6J8SvX99+LAw8tmJfHq2FalmvcWjK0kZR/G8cpvdZLZtCXxZ0 zQJn7khR9LJBFK5xhsgDaPnVXfX1k08BQfOTZV95DXCh9nuCGs+TjEL0pRcR1wWKu7Iq XPfqjJsATRxE7whqAGuxwdZVindezOw6oHWwJjiSPy+6TURo+JD7noUdlDfgwetMnn0h O2VQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777679108; x=1778283908; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=x3HMy/5x+GTu/U/2MxeUBt4BoOwWC+Ga4gJ09h6qLJI=; b=NHrDIqMgqouBuX/D25zZdC+B3kgbY+iIPc6H8zO4X0vrqJ28OKPTu7Ke8XARKoA6uA bkUjr2uQtwSRt+HiT2elwp0z4p0ia1yhUCNlN6kWqasI1cJFlMvMAedjd5FP7LoYTDzg D9gVgoF5cj0FbXBcTjID5+4F3uhzixNdvsMbXLj8JTpFawGJ2vwbRBfk1q06V4VKxPAf rBGmOED75+/2g9RuPbtKtIuXBZrR5AsZjfD5ZOP3u5Liqr1U7fYrjqCYotb3luiYCpMz I/3rULCNY5MM0U9yNhHdZYpCnLuqktbX+C0GNe6yP8LhzjQN0y/TyWXis2k7+9CLKstl s03Q== X-Forwarded-Encrypted: i=1; AFNElJ9f8B7rOrVjaNAlzG1Scn4rL6bSlfsutavtmh3XZ1epc1NR/rlpqW7mYmTd5eD73Ee0u5T1eQM0cA1+aeQ=@vger.kernel.org X-Gm-Message-State: AOJu0YwG0xAUEy4bXNCSm+hxpSdnf4hIq5U4Iuz+U4sG2w1/J9+R1xdg vRror56e6howcPD27tb96X4JemmYB8TFL9yaRMjApC6ye9HomN3BDXJk X-Gm-Gg: AeBDiesJqbB9JJ6JGuKv1wFcIZdG/7NTnACfHl6uWRbFBHxNKIYNMXR8q2AX0qJGgnD 4QFG10wz47FtAEJdnk3zxFE+zxeleihlloTtBbZIqeaJW1oPtftfZya4bJMxhvfmge8FRgcPVZV eSLK3G+XXW2UdKFnNVVqitPPSuhs8EPXrK1IEHQaRUpbjY/VLrD8iH9mKwmi4b5VSzMG4nuRkcB X/wOi9g3A8Xc1SUH9bmBNN7KPKccx8kRo541hrvXdvBO5Z7t1YndfHOEo+rcetjiXCZU59QG1RO kaJ8Z1rEe+0Kcci9dHEIibMFss45FfyJv7yPhw5Zn4yzHgX3BYwgadA1IanP1ZMvFlVmMzYyf7B cWmEFndYWGh2h3RYnMf5IYBo+d4leAtPMCNx3lV6JB+JJ+IdSim9wH8NSllqsXx/e6JzNkJCvZA +16puk/+6tYYz+XpxcR/bFZXV9KJml/Q== X-Received: by 2002:a05:6a00:4c1c:b0:82d:5da9:adbf with SMTP id d2e1a72fcca58-8352d2833ffmr978243b3a.41.1777679107458; Fri, 01 May 2026 16:45:07 -0700 (PDT) Received: from localhost ([121.237.249.41]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-83515b863eesm3448460b3a.60.2026.05.01.16.45.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 01 May 2026 16:45:06 -0700 (PDT) From: Coiby Xu To: kexec@lists.infradead.org Cc: Andrew Morton , Sourabh Jain , Baoquan He , Dave Young , Mike Rapoport , Pasha Tatashin , Pratyush Yadav , Jonathan Corbet , Shuah Khan , Coiby Xu , linux-doc@vger.kernel.org (open list:DOCUMENTATION), linux-kernel@vger.kernel.org (open list) Subject: [PATCH v2 8/9] crash_dump: Disallow configfs/crash_dm_crypt_key/reuse if CONFIG_CRASH_HOTPLUG enabled Date: Sat, 2 May 2026 07:43:37 +0800 Message-ID: <20260501234342.2518281-9-coiby.xu@gmail.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260501234342.2518281-1-coiby.xu@gmail.com> References: <20260501234342.2518281-1-coiby.xu@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit If CONFIG_CRASH_HOTPLUG is enabled, dm-crypt keys saved to reserved memory will be took care of automatically. Thus it doesn't make sense to use configfs/crash_dm_crypt_key/reuse. Reserving image->dm_crypt_keys_addr is also unnecessary. Currently x86_64 and ppc64le have implemented CONFIG_CRASH_HOTPLUG feature. Also update the doc accordingly. Note two doc issues are fixed as well. Fixes: 9ebfa8dcaea7 ("crash_dump: reuse saved dm crypt keys for CPU/memory hot-plugging") Signed-off-by: Coiby Xu --- Documentation/admin-guide/kdump/kdump.rst | 9 ++++++--- kernel/crash_dump_dm_crypt.c | 14 +++++++++++--- 2 files changed, 17 insertions(+), 6 deletions(-) diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst index 7587caadbae1..73f2e9500c60 100644 --- a/Documentation/admin-guide/kdump/kdump.rst +++ b/Documentation/admin-guide/kdump/kdump.rst @@ -577,9 +577,10 @@ with /sys/kernel/config/crash_dm_crypt_keys for setup, 1. Tell the first kernel what logon keys are needed to unlock the disk volumes, # Add key #1 - mkdir /sys/kernel/config/crash_dm_crypt_keys/7d26b7b4-e342-4d2d-b660-7426b0996720 + VOL1_UUID=7d26b7b4-e342-4d2d-b660-7426b0996720 + mkdir /sys/kernel/config/crash_dm_crypt_keys/$VOL1_UUID # Add key #1's description - echo cryptsetup:7d26b7b4-e342-4d2d-b660-7426b0996720 > /sys/kernel/config/crash_dm_crypt_keys/description + echo cryptsetup:$VOL1_UUID > /sys/kernel/config/crash_dm_crypt_keys/$VOL1_UUID/description # how many keys do we have now? cat /sys/kernel/config/crash_dm_crypt_keys/count @@ -593,7 +594,9 @@ with /sys/kernel/config/crash_dm_crypt_keys for setup, # To support CPU/memory hot-plugging, reuse keys already saved to reserved # memory - echo true > /sys/kernel/config/crash_dm_crypt_key/reuse + # Note if CONFIG_CRASH_HOTPLUG is enabled, this API is totally unnecessary + # thus will be disabled. + echo true > /sys/kernel/config/crash_dm_crypt_keys/reuse 2. Load the dump-capture kernel diff --git a/kernel/crash_dump_dm_crypt.c b/kernel/crash_dump_dm_crypt.c index 36e51807d94f..7a7cae17f578 100644 --- a/kernel/crash_dump_dm_crypt.c +++ b/kernel/crash_dump_dm_crypt.c @@ -304,6 +304,11 @@ static ssize_t config_keys_reuse_store(struct config_item *item, bool val; int r; + if (IS_ENABLED(CONFIG_CRASH_HOTPLUG)) { + pr_info("CONFIG_CRASH_HOTPLUG already enabled"); + return -EINVAL; + } + if (!kexec_crash_image || !kexec_crash_image->dm_crypt_keys_addr) { pr_info("dm-crypt keys haven't be saved to crash-reserved memory\n"); return -EINVAL; @@ -486,15 +491,18 @@ int crash_load_dm_crypt_keys(struct kimage *image) void kexec_file_post_load_cleanup_dm_crypt(struct kimage *image) { /* - * For CPU/memory hot-plugging, the kdump image will be reloaded. Prevent - * keys_header from being cleaned up during unloading when - * is_dm_key_reused=true + * For CPU/memory hot-plugging without CONFIG_CRASH_HOTPLUG, the whole kdump + * image will be reloaded. Prevent keys_header from being cleaned up during + * unloading when is_dm_key_reused=true */ if (!is_dm_key_reused) { kfree_sensitive(keys_header); keys_header = NULL; } + if (IS_ENABLED(CONFIG_CRASH_HOTPLUG)) + image->dm_crypt_keys_addr = 0; + if (mutex_is_locked(&config_keys_subsys.su_mutex)) mutex_unlock(&config_keys_subsys.su_mutex); } -- 2.54.0