From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f41.google.com (mail-ed1-f41.google.com [209.85.208.41]) (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 0CC102C327E for ; Wed, 4 Jun 2025 10:55:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.41 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749034503; cv=none; b=kDDXBZiu78fAA1UXhaitiyGReShXvxRNMIvHTJn7dPyZjTjO5rwzVOIpBvz42m1QeKCj3QdccSREBU3Ab5k6IE1xbkrEg827MsXXRJ9LFdQOADAxQofyku3hT2hoRb9cuQyIWzU98tqoky8WCyIFnHkF7BKTVCsWO6vYod11n2c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749034503; c=relaxed/simple; bh=wHcPCwGxUmVNyXsXAbEWS06LpX11YizruvdQuxUc2nc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=rDGuooB/k3qgXQOP0zihwieISKhlVg+UzKzV5R++w7Bug9oIfihSNDYwVGZQKU0dUhsNAsvy5qX2WCMRrw3IUEwz1ZXiQJ55uN9/0K0KtSpL18QasmjO/fXINhjAfsI3s49wCpEIjs3EXo8RGsgAl+XGQTGqZNPFOs4DItCkNNw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b=DmqZ2f/7; arc=none smtp.client-ip=209.85.208.41 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b="DmqZ2f/7" Received: by mail-ed1-f41.google.com with SMTP id 4fb4d7f45d1cf-60477f1a044so11461896a12.0 for ; Wed, 04 Jun 2025 03:55:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1749034499; x=1749639299; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:autocrypt:content-language :from:references:cc:to:subject:user-agent:mime-version:date :message-id:from:to:cc:subject:date:message-id:reply-to; bh=RQiFSzh7MNKglOz6npvfpvqQ53FTFZpnQ2JPeQGyeBo=; b=DmqZ2f/7xb7Sv7MfX9F9zhrxevIp647ORCu2vS/sESxgAngqoo0650o7xXbZVUhUBR z+o/OYGdcbyoyINPZpNP/r1+lhsmRCvwFfJjJduLz5/dfNPFByjK6XflB3FX0yQuoROy qbKogYgRErElOVgp1B2Dfhlk2rI7hRWLM+5dOizF5rTsqpj4gATOql2pr1fAe8Wdr9WB j8hrLJ/Ihp7dgxQ4Aqzm2S8bbPvN2IgcOT4gK4TeSB8XGxkhNzHwDUraJbpIsCVHXSrM z4FC84AOLkC8vXT4ITWsL8G0/9dYKt+1lUqVrksb56c6LC6fuyLRfLB48KUyqnvjC2PB oSMQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1749034499; x=1749639299; h=content-transfer-encoding:in-reply-to:autocrypt:content-language :from:references:cc:to:subject:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=RQiFSzh7MNKglOz6npvfpvqQ53FTFZpnQ2JPeQGyeBo=; b=LGhVZ4vL/OUMYym3hfPELuTLKYbgFD6zRUOp4jv2XoX/9lGdIuNGQWJ7GmB+/Ef9oa 0BPjP/5HvQaDKkj3W23bvnoB+gioW721VYZjEJbDoyrfkanwGJJvtENfBQ6Ma3zbMytf wyOV9TPEk9aA4WCOoMLcel3dvM3FLKSqLeodqPeQTfAVO05Ck4Ujpx425MsuxaGsB+V4 Ug92KE3Qbi/ed9xxSird8ZOn2mEglBYSty9fcewjzAwcOlXZiWfWJvktFWL+y/7s+leA 4y52rPDeN81+v5AV/ubDmcMpgjfUXCID/D7nVWQZo18A9Dk9BKWbT6Q8Y81DoydWpzz9 IaNw== X-Forwarded-Encrypted: i=1; AJvYcCXVFx8QvMiuG5QKBVr3XoFz9/4Z2QZTjo0eTPVVQBLi5RzKdpabwreTHz6ebsu5kQnS/HgtyP896geTGfs=@vger.kernel.org X-Gm-Message-State: AOJu0Yzl/SQtj36Zdhe+W92PLZnsgWT9RWhknq4v3bDizO7lW4ScHHpV AvfjLuBVQ7LUr9+ED9pwu+a+ovik5of8rhVOOP7c2xQsqHxBbBDQj832PdyPDpUMzUQytcGzpzm WJ9rs X-Gm-Gg: ASbGnctHNXlbrdpQTWpkPc2SP6s0sz2QasbFfJIlNHYz7VjGNe5seUknDcF84zHhv51 IypEIwSsnenemx23SK/AB4nY655ywVGTN/9GQZdu5r6oKFi2BUI2KEOeJP4ZZkbNz9Ujyw1532Z Y54PPRdmVD03bnYBN2pVy7WBLV7hxIFbyxu5DesUuQOJKsYS2kFUbrDqnvYPm9xGCLp1KYGvY+g 3abMyBTiO2RD8jo257JIzyL6V+nARz2fkcOJZks/uWWvMFPBH0V77yTcsEai1ks3M+7dzWUKaai 07CkjrF3fNPel16ypJGkeDGZYXAaBoXh5Knjm2hAtdLf+/+RcWrnGESM X-Google-Smtp-Source: AGHT+IFP6tIqlCqjMTmuclDNXygh6kzxDV1hmxofL/JCB/Rdjr7vcC3zqFjLhJMAwf2l24JZ8HagTA== X-Received: by 2002:a17:906:4fc7:b0:adb:2bb2:ed1 with SMTP id a640c23a62f3a-addf8f24e35mr197693166b.40.1749034499177; Wed, 04 Jun 2025 03:54:59 -0700 (PDT) Received: from [192.168.0.20] ([212.21.159.167]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-adb390f09d7sm844311066b.148.2025.06.04.03.54.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 04 Jun 2025 03:54:58 -0700 (PDT) Message-ID: <73aaf67c-3ece-4a9f-989d-a1d4aae6ab69@suse.com> Date: Wed, 4 Jun 2025 13:54:57 +0300 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] x86/its: Always return a writable page for dynamic thunks To: x86@kernel.org Cc: pawan.kumar.gupta@linux.intel.com, peterz@infradead.org, linux-kernel@vger.kernel.org, dave.hansen@linux.intel.com References: <20250604104715.700149-1-nik.borisov@suse.com> From: Nikolay Borisov Content-Language: en-US Autocrypt: addr=nik.borisov@suse.com; keydata= xsFNBGcrpvIBEAD5cAR5+qu30GnmPrK9veWX5RVzzbgtkk9C/EESHy9Yz0+HWgCVRoNyRQsZ 7DW7vE1KhioDLXjDmeu8/0A8u5nFMqv6d1Gt1lb7XzSAYw7uSWXLPEjFBtz9+fBJJLgbYU7G OpTKy6gRr6GaItZze+r04PGWjeyVUuHZuncTO7B2huxcwIk9tFtRX21gVSOOC96HcxSVVA7X N/LLM2EOL7kg4/yDWEhAdLQDChswhmdpHkp5g6ytj9TM8bNlq9I41hl/3cBEeAkxtb/eS5YR 88LBb/2FkcGnhxkGJPNB+4Siku7K8Mk2Y6elnkOctJcDvk29DajYbQnnW4nhfelZuLNupb1O M0912EvzOVI0dIVgR+xtosp66bYTOpX4Xb0fylED9kYGiuEAeoQZaDQ2eICDcHPiaLzh+6cc pkVTB0sXkWHUsPamtPum6/PgWLE9vGI5s+FaqBaqBYDKyvtJfLK4BdZng0Uc3ijycPs3bpbQ bOnK9LD8TYmYaeTenoNILQ7Ut54CCEXkP446skUMKrEo/HabvkykyWqWiIE/UlAYAx9+Ckho TT1d2QsmsAiYYWwjU8igXBecIbC0uRtF/cTfelNGrQwbICUT6kJjcOTpQDaVyIgRSlUMrlNZ XPVEQ6Zq3/aENA8ObhFxE5PLJPizJH6SC89BMKF3zg6SKx0qzQARAQABzSZOaWtvbGF5IEJv cmlzb3YgPG5pay5ib3Jpc292QHN1c2UuY29tPsLBkQQTAQoAOxYhBDuWB8EJLBUZCPjT3SRn XZEnyhfsBQJnK6byAhsDBQsJCAcCAiICBhUKCQgLAgQWAgMBAh4HAheAAAoJECRnXZEnyhfs XbIQAJxuUnelGdXbSbtovBNm+HF3LtT0XnZ0+DoR0DemUGuA1bZAlaOXGr5mvVbTgaoGUQIJ 3Ejx3UBEG7ZSJcfJobB34w1qHEDO0pN9orGIFT9Bic3lqhawD2r85QMcWwjsZH5FhyRx7P2o DTuUClLMO95GuHYQngBF2rHHl8QMJPVKsR18w4IWAhALpEApxa3luyV7pAAqKllfCNt7tmed uKmclf/Sz6qoP75CvEtRbfAOqYgG1Uk9A62C51iAPe35neMre3WGLsdgyMj4/15jPYi+tOUX Tc7AAWgc95LXyPJo8069MOU73htZmgH4OYy+S7f+ArXD7h8lTLT1niff2bCPi6eiAQq6b5CJ Ka4/27IiZo8tm1XjLYmoBmaCovqx5y5Xt2koibIWG3ZGD2I+qRwZ0UohKRH6kKVHGcrmCv0J YO8yIprxgoYmA7gq21BpTqw3D4+8xujn/6LgndLKmGESM1FuY3ymXgj5983eqaxicKpT9iq8 /a1j31tms4azR7+6Dt8H4SagfN6VbJ0luPzobrrNFxUgpjR4ZyQQ++G7oSRdwjfIh1wuCF6/ mDUNcb6/kA0JS9otiC3omfht47yQnvod+MxFk1lTNUu3hePJUwg1vT1te3vO5oln8lkUo9BU knlYpQ7QA2rDEKs+YWqUstr4pDtHzwQ6mo0rqP+zzsFNBGcrpvIBEADGYTFkNVttZkt6e7yA LNkv3Q39zQCt8qe7qkPdlj3CqygVXfw+h7GlcT9fuc4kd7YxFys4/Wd9icj9ZatGMwffONmi LnUotIq2N7+xvc4Xu76wv+QJpiuGEfCDB+VdZOmOzUPlmMkcJc/EDSH4qGogIYRu72uweKEq VfBI43PZIGpGJ7TjS3THX5WVI2YNSmuwqxnQF/iVqDtD2N72ObkBwIf9GnrOgxEyJ/SQq2R0 g7hd6IYk7SOKt1a8ZGCN6hXXKzmM6gHRC8fyWeTqJcK4BKSdX8PzEuYmAJjSfx4w6DoxdK5/ 9sVrNzaVgDHS0ThH/5kNkZ65KNR7K2nk45LT5Crjbg7w5/kKDY6/XiXDx7v/BOR/a+Ryo+lM MffN3XSnAex8cmIhNINl5Z8CAvDLUtItLcbDOv7hdXt6DSyb65CdyY8JwOt6CWno1tdjyDEG 5ANwVPYY878IFkOJLRTJuUd5ltybaSWjKIwjYJfIXuoyzE7OL63856MC/Os8PcLfY7vYY2LB cvKH1qOcs+an86DWX17+dkcKD/YLrpzwvRMur5+kTgVfXcC0TAl39N4YtaCKM/3ugAaVS1Mw MrbyGnGqVMqlCpjnpYREzapSk8XxbO2kYRsZQd8J9ei98OSqgPf8xM7NCULd/xaZLJUydql1 JdSREId2C15jut21aQARAQABwsF2BBgBCgAgFiEEO5YHwQksFRkI+NPdJGddkSfKF+wFAmcr pvICGwwACgkQJGddkSfKF+xuuxAA4F9iQc61wvAOAidktv4Rztn4QKy8TAyGN3M8zYf/A5Zx VcGgX4J4MhRUoPQNrzmVlrrtE2KILHxQZx5eQyPgixPXri42oG5ePEXZoLU5GFRYSPjjTYmP ypyTPN7uoWLfw4TxJqWCGRLsjnkwvyN3R4161Dty4Uhzqp1IkNhl3ifTDYEvbnmHaNvlvvna 7+9jjEBDEFYDMuO/CA8UtoVQXjy5gtOhZZkEsptfwQYc+E9U99yxGofDul7xH41VdXGpIhUj 4wjd3IbgaCiHxxj/M9eM99ybu5asvHyMo3EFPkyWxZsBlUN/riFXGspG4sT0cwOUhG2ZnExv XXhOGKs/y3VGhjZeCDWZ+0ZQHPCL3HUebLxW49wwLxvXU6sLNfYnTJxdqn58Aq4sBXW5Un0Q vfbd9VFV/bKFfvUscYk2UKPi9vgn1hY38IfmsnoS8b0uwDq75IBvup9pYFyNyPf5SutxhFfP JDjakbdjBoYDWVoaPbp5KAQ2VQRiR54lir/inyqGX+dwzPX/F4OHfB5RTiAFLJliCxniKFsM d8eHe88jWjm6/ilx4IlLl9/MdVUGjLpBi18X7ejLz3U2quYD8DBAGzCjy49wJ4Di4qQjblb2 pTXoEyM2L6E604NbDu0VDvHg7EXh1WwmijEu28c/hEB6DwtzslLpBSsJV0s1/jE= In-Reply-To: <20250604104715.700149-1-nik.borisov@suse.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 6/4/25 13:47, Nikolay Borisov wrote: > its_alloc unconditionally allocates and return a ROX page, but setting > it RW is predicated on its_mod being set. This can cause a #GP on the > memset in its_allocate_thunk() if its_mod is not set. > > Since the function always returns a page, ensure it's always set > writable so it can be initialized properly. > > Fixes: 872df34d7c51 ("x86/its: Use dynamic thunks for indirect branches") > Signed-off-by: Nikolay Borisov > --- > arch/x86/kernel/alternative.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c > index ecfe7b497cad..191e909636a5 100644 > --- a/arch/x86/kernel/alternative.c > +++ b/arch/x86/kernel/alternative.c > @@ -199,6 +199,8 @@ static void *its_alloc(void) > if (!page) > return NULL; > > + execmem_make_temp_rw(page, PAGE_SIZE); Actually this is not sufficient, in case we don't have its_mod set ergo its_fini_mod won't be executed I guess execmem_restore_rox should also be executed in its_allocate_thunk iff its_mod is not set? > + > #ifdef CONFIG_MODULES > if (its_mod) { > void *tmp = krealloc(its_mod->its_page_array, > @@ -210,7 +212,6 @@ static void *its_alloc(void) > its_mod->its_page_array = tmp; > its_mod->its_page_array[its_mod->its_num_pages++] = page; > > - execmem_make_temp_rw(page, PAGE_SIZE); > } > #endif /* CONFIG_MODULES */ >