From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AC259C433EF for ; Sat, 19 Feb 2022 02:34:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241112AbiBSCfI (ORCPT ); Fri, 18 Feb 2022 21:35:08 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:32906 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241082AbiBSCfG (ORCPT ); Fri, 18 Feb 2022 21:35:06 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 15D8D5677B for ; Fri, 18 Feb 2022 18:34:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1645238087; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=dLSRXD4oabvT1hZcyTh/jopmei8mV6oK1K/s3P1srU8=; b=GHmwdxhFtA5RB9nqjxqHCv7jaEl7dw9yUZNNex57//r75TSXkG+V4NPldYfolJsZqQNcOR avtJuivosnJojI4xvvjyVlPFWceBn7Ed516zOc8lDWLeTVXWxl/q0dK+HxCBOqysL51Nzk jfLZNdVGBCVx++m7SbqmtzdL5b62lX8= Received: from mail-qk1-f198.google.com (mail-qk1-f198.google.com [209.85.222.198]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-228-EtZauZ8UOgmGSaugsWlrLw-1; Fri, 18 Feb 2022 21:34:45 -0500 X-MC-Unique: EtZauZ8UOgmGSaugsWlrLw-1 Received: by mail-qk1-f198.google.com with SMTP id 2-20020a370a02000000b0060df1ac78baso5007293qkk.20 for ; Fri, 18 Feb 2022 18:34:45 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=dLSRXD4oabvT1hZcyTh/jopmei8mV6oK1K/s3P1srU8=; b=LIt21kJ9ZrpY8EgpX89uRgRFHAJvV6exiuLNVaWcfoqmu6jjBuKqWhs/Q/ypB8e/7W zJo5Yf3r4c3ATeVZMaxr1OWBEOL5zGBizKfkdx9r79DzLREiZaSFSleo9kMN3mG/ZSM8 gq6or2MuUVBdcv4GGbkT5FAArErPQ/UrDTJ3Rzd0rDF4cQQPr4VzGjE3ed9ZS7NeGfzU yCIqx4tiiftCg1IUdOncGf+rGcRbF5R5OgA1xjgC1jCGNRmT+GR0b3cKiv64Yjfk9WZA cw98cexUS+YY04vD5IXP4GJNToZaEo0Hcn3iqizOVBWfCCulgHdHw83Eq+T4povV7L8v KHzw== X-Gm-Message-State: AOAM533RbpCxVc+JCfSQpKZcpoz5Sgq2dBymHpsjqSt/Ya8O8CVUPWtU FRZwkWe5sUgS+qhQj075/gZ+E11vCpZzfli+Zb/oGEt4UHdFER6fMufXu7n7XIb9nrpr52mwrbL QOxL41JABd/bB/YFhI9LxcDQj X-Received: by 2002:a05:622a:255:b0:2dd:2295:e6cc with SMTP id c21-20020a05622a025500b002dd2295e6ccmr9237071qtx.399.1645238085426; Fri, 18 Feb 2022 18:34:45 -0800 (PST) X-Google-Smtp-Source: ABdhPJycI8i/Dj3TSf78qpp+mi+i6jw4nt8X0/VpHah9pqOsogHlS9ItFFm2kFqJ/p1eOKjjqDzKmw== X-Received: by 2002:a05:622a:255:b0:2dd:2295:e6cc with SMTP id c21-20020a05622a025500b002dd2295e6ccmr9237062qtx.399.1645238085204; Fri, 18 Feb 2022 18:34:45 -0800 (PST) Received: from localhost.localdomain (024-205-208-113.res.spectrum.com. [24.205.208.113]) by smtp.gmail.com with ESMTPSA id f14sm23160886qko.117.2022.02.18.18.34.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 18 Feb 2022 18:34:44 -0800 (PST) Subject: Re: [PATCH] drm/amdkfd: rework criu_restore_bos error handling To: Felix Kuehling , alexander.deucher@amd.com, christian.koenig@amd.com, Xinhui.Pan@amd.com, airlied@linux.ie, daniel@ffwll.ch, nathan@kernel.org, ndesaulniers@google.com, david.yatsin@amd.com, rajneesh.bhardwaj@amd.com Cc: amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev References: <20220218173913.3376948-1-trix@redhat.com> From: Tom Rix Message-ID: <4ca24c08-9014-3380-b8cc-dc0ed9a01a73@redhat.com> Date: Fri, 18 Feb 2022 18:34:41 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/18/22 10:35 AM, Felix Kuehling wrote: > Am 2022-02-18 um 12:39 schrieb trix@redhat.com: >> From: Tom Rix >> >> Clang static analysis reports this problem >> kfd_chardev.c:2327:2: warning: 1st function call argument >>    is an uninitialized value >>    kvfree(bo_privs); >>    ^~~~~~~~~~~~~~~~ >> >> If the copy_from_users(bo_buckets, ...) fails, there is a jump to >> the generic error handler at exit:.  The freeing of bo_privs and >> unwinding of the dmabuf_fd loop do not need to be done. >> >> Add some specific labels for the early failures. >> Reorder the frees to be the reverse of their allocs. >> >> Move the initialize of 'i' back to the loop. >> The problem with the early frees predates the loop >> unwinding problem. > > I think the existing error handling strategy in this function is fine. > Having only one exit label avoids potential issues when using the > wrong label. Freeing NULL pointers is not a problem. The loop becomes > a noop if i==0 (this was fixed by you in a previous patch). The only > real problem I see is that bo_privs is not initialized. So this should > really be a one-line or maybe two-line fix: > >     struct kfd_criu_bo_bucket *bo_buckets = NULL; >     struct kfd_criu_bo_priv_data *bo_privs = NULL; This is the other way I considered to fix the problem. So it will work. Tom > > Regards, >   Felix > > >> >> Fixes: 73fa13b6a511 ("drm/amdkfd: CRIU Implement KFD restore ioctl") >> Signed-off-by: Tom Rix >> --- >>   drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 15 +++++++++------ >>   1 file changed, 9 insertions(+), 6 deletions(-) >> >> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c >> b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c >> index 965af2a08bc0..1d5f41ac3832 100644 >> --- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c >> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c >> @@ -2102,7 +2102,7 @@ static int criu_restore_bos(struct kfd_process *p, >>       const bool criu_resume = true; >>       bool flush_tlbs = false; >>       int ret = 0, j = 0; >> -    uint32_t i = 0; >> +    uint32_t i; >>         if (*priv_offset + (args->num_bos * sizeof(*bo_privs)) > >> max_priv_data_size) >>           return -EINVAL; >> @@ -2119,13 +2119,13 @@ static int criu_restore_bos(struct >> kfd_process *p, >>       if (ret) { >>           pr_err("Failed to copy BOs information from user\n"); >>           ret = -EFAULT; >> -        goto exit; >> +        goto free_buckets; >>       } >>         bo_privs = kvmalloc_array(args->num_bos, sizeof(*bo_privs), >> GFP_KERNEL); >>       if (!bo_privs) { >>           ret = -ENOMEM; >> -        goto exit; >> +        goto free_buckets; >>       } >>         ret = copy_from_user(bo_privs, (void __user *)args->priv_data >> + *priv_offset, >> @@ -2133,12 +2133,12 @@ static int criu_restore_bos(struct >> kfd_process *p, >>       if (ret) { >>           pr_err("Failed to copy BOs information from user\n"); >>           ret = -EFAULT; >> -        goto exit; >> +        goto free_privs; >>       } >>       *priv_offset += args->num_bos * sizeof(*bo_privs); >>         /* Create and map new BOs */ >> -    for (; i < args->num_bos; i++) { >> +    for (i = 0; i < args->num_bos; i++) { >>           struct kfd_criu_bo_bucket *bo_bucket; >>           struct kfd_criu_bo_priv_data *bo_priv; >>           struct kfd_dev *dev; >> @@ -2323,8 +2323,11 @@ static int criu_restore_bos(struct kfd_process >> *p, >>           if (bo_buckets[i].alloc_flags & KFD_IOC_ALLOC_MEM_FLAGS_VRAM) >>               close_fd(bo_buckets[i].dmabuf_fd); >>       } >> -    kvfree(bo_buckets); >> +free_privs: >>       kvfree(bo_privs); >> +free_buckets: >> +    kvfree(bo_buckets); >> + >>       return ret; >>   } >