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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id A7820C3DA5D for ; Thu, 25 Jul 2024 06:08:59 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0CA766B007B; Thu, 25 Jul 2024 02:08:59 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 07B2B6B0082; Thu, 25 Jul 2024 02:08:59 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E84706B0083; Thu, 25 Jul 2024 02:08:58 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id C9F566B007B for ; Thu, 25 Jul 2024 02:08:58 -0400 (EDT) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 4A4C9160E3A for ; Thu, 25 Jul 2024 06:08:58 +0000 (UTC) X-FDA: 82377246756.21.465F67D Received: from mail-lf1-f49.google.com (mail-lf1-f49.google.com [209.85.167.49]) by imf09.hostedemail.com (Postfix) with ESMTP id 2F62914000A for ; Thu, 25 Jul 2024 06:08:55 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=suse.com header.s=google header.b=Geylepmn; spf=pass (imf09.hostedemail.com: domain of mhocko@suse.com designates 209.85.167.49 as permitted sender) smtp.mailfrom=mhocko@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1721887698; h=from:from:sender: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:dkim-signature; bh=zbstpGz3BJoh4Yi4J8FfFAsfYZOmCWi0WHOoaHkQIeM=; b=dzrvG1kEaw1yTMGBWcV48QDE9xSMZid1MjH4IgRJsp+kJbo4XyQdHY4BsLwbyBmsGJavhP yeoUZOn7nX0aW+FF74b2y4EHbMkvPn9bs0CnLuImT5E1aoq48epcn7Kx0rJ63pykl0es4q uwUICpLWh928s1n/VS0RRFc9XO7kK4M= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=suse.com header.s=google header.b=Geylepmn; spf=pass (imf09.hostedemail.com: domain of mhocko@suse.com designates 209.85.167.49 as permitted sender) smtp.mailfrom=mhocko@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1721887698; a=rsa-sha256; cv=none; b=YLLP+tuV9QpBeePn2u59FTbdwFU7K1WDp5MnpiM0BZJkEw2ZZchHOPYCxz4A6mh7zT9DTj D0RRTo4IRYsVhjegE7AZQgnZJWsCsK1/Fa/SaC+p30n1iprbtMQdr3Kf1gNWeV4NiiuhWc kchWM4h6EoQu3tSDP1lqCS5VA+3/GdU= Received: by mail-lf1-f49.google.com with SMTP id 2adb3069b0e04-52efabf5d7bso474544e87.1 for ; Wed, 24 Jul 2024 23:08:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1721887734; x=1722492534; darn=kvack.org; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=zbstpGz3BJoh4Yi4J8FfFAsfYZOmCWi0WHOoaHkQIeM=; b=GeylepmnIdSJUeU4ziGgPN9AeZ6bSaECdHhY6KS1veD5lWE+sDqlTfxYADcSFx5hco b8YSzGpo3XVAULNmoUv91LDX5+99WgJOkEo/XUhMG9wS3oKgna4M8hjtQ9TXSo+c9ZQ9 N5OUcIJQi+X8NLrONDHqQ/HIBA4PJgAmaTI1/Sq/A28FP6dk0qPmfbYHTfUsBy/XK7+7 MwDo1RAxBSBJFhTx6voVtyM2pQNoA6/hAeLt3yARu1F+6S0qdsHAHUCbtJbyl0NoDhXa KbbYili9w9q4cwX3o0PokkHhWbPKZ/w4sPeFtCjaDR4la0pqCp592vi9EXCxfdo5GwtO fouA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1721887734; x=1722492534; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=zbstpGz3BJoh4Yi4J8FfFAsfYZOmCWi0WHOoaHkQIeM=; b=OgUqy2rCsf7f//Q4I3L3yra5yux20IX1LRuFYM4OUsGxHqGWYOmZ5ufXbxel1gMwWF UBNhJfCT4guxDyL0kJNyIsFMcp2gSmcjXjPqJq0LFlsYxoHTk9avL1aBoA/4bXTaobPI N+YEMyqJx8nYyXabFmlrhqopvdI8IsmRuNs6DObsvbQ+UNggztfSwQ6PhMbcSyBmAI1j DRL3B0qlK+A7xCxyZaeY30oOX9xtXHny1R5lEPCGCVvH8F7GFS38DC6TsZDRI8Ni2Mn5 zqOjz1ePi+jvxg0vYuB11ntfGlj4kIahJP+UE3Sp5WZcsN/voMNXTh+Rk+FIy9jL/ADs OM0Q== X-Forwarded-Encrypted: i=1; AJvYcCV35PANQ/0qByOphT6KnkDJW1Qa5dZVvOZpx5yvrwOoikD/9ztoWdk9GGUHQM8lU8W2FNnMMhKf10wemr4+WgAfLRA= X-Gm-Message-State: AOJu0YyyGs7hjeCVxZS+prbNHlMLi5jvkYjQ6qctBWewGhr2yVPt5xun ULpV8NTAD3y0CkeL28rQDYZUo1zeTh/EjIyv2dDPuplXoMCvkWggOeCbXAbS4aM= X-Google-Smtp-Source: AGHT+IHHRod0kPEF7TumO/KmS3bpcIdRG7a5qChmWx75LylMoQL7VSxZYZyaTpHk0ms/RvJrkTaunw== X-Received: by 2002:ac2:4e09:0:b0:52e:943c:c61a with SMTP id 2adb3069b0e04-52fd3f864c9mr1289601e87.57.1721887734191; Wed, 24 Jul 2024 23:08:54 -0700 (PDT) Received: from localhost (109-81-83-231.rct.o2.cz. [109.81.83.231]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-a7acadb9f60sm34656266b.223.2024.07.24.23.08.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 24 Jul 2024 23:08:53 -0700 (PDT) Date: Thu, 25 Jul 2024 08:08:52 +0200 From: Michal Hocko To: Barry Song <21cnbao@gmail.com> Cc: akpm@linux-foundation.org, linux-mm@kvack.org, 42.hyeyoo@gmail.com, cl@linux.com, hch@infradead.org, iamjoonsoo.kim@lge.com, lstoakes@gmail.com, penberg@kernel.org, rientjes@google.com, roman.gushchin@linux.dev, urezki@gmail.com, v-songbaohua@oppo.com, vbabka@suse.cz, virtualization@lists.linux.dev, hailong.liu@oppo.com, torvalds@linux-foundation.org, "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , Eugenio =?iso-8859-1?Q?P=E9rez?= , Maxime Coquelin Subject: Re: [PATCH RFC 1/5] vpda: try to fix the potential crash due to misusing __GFP_NOFAIL Message-ID: References: <20240724085544.299090-1-21cnbao@gmail.com> <20240724085544.299090-2-21cnbao@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Stat-Signature: augttrc79f6pfph6ksrwx7s5imcik6am X-Rspam-User: X-Rspamd-Queue-Id: 2F62914000A X-Rspamd-Server: rspam02 X-HE-Tag: 1721887735-837963 X-HE-Meta: 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 9f6v8MZO 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu 25-07-24 10:50:45, Barry Song wrote: > On Thu, Jul 25, 2024 at 12:27 AM Michal Hocko wrote: > > > > On Wed 24-07-24 20:55:40, Barry Song wrote: [...] > > > diff --git a/drivers/vdpa/vdpa_user/iova_domain.c b/drivers/vdpa/vdpa_user/iova_domain.c > > > index 791d38d6284c..eff700e5f7a2 100644 > > > --- a/drivers/vdpa/vdpa_user/iova_domain.c > > > +++ b/drivers/vdpa/vdpa_user/iova_domain.c > > > @@ -287,28 +287,44 @@ void vduse_domain_remove_user_bounce_pages(struct vduse_iova_domain *domain) > > > { > > > struct vduse_bounce_map *map; > > > unsigned long i, count; > > > + struct page **pages = NULL; > > > > > > write_lock(&domain->bounce_lock); > > > if (!domain->user_bounce_pages) > > > goto out; > > > - > > > count = domain->bounce_size >> PAGE_SHIFT; > > > + write_unlock(&domain->bounce_lock); > > > + > > > + pages = kmalloc_array(count, sizeof(*pages), GFP_KERNEL | __GFP_NOFAIL); > > > + for (i = 0; i < count; i++) > > > + pages[i] = alloc_page(GFP_KERNEL | __GFP_NOFAIL); > > > > AFAICS vduse_domain_release calls this function with > > spin_lock(&domain->iotlb_lock) so dropping &domain->bounce_lock is not > > sufficient. > > yes. this is true: > > static int vduse_domain_release(struct inode *inode, struct file *file) > { > struct vduse_iova_domain *domain = file->private_data; > > spin_lock(&domain->iotlb_lock); > vduse_iotlb_del_range(domain, 0, ULLONG_MAX); > vduse_domain_remove_user_bounce_pages(domain); > vduse_domain_free_kernel_bounce_pages(domain); > spin_unlock(&domain->iotlb_lock); > put_iova_domain(&domain->stream_iovad); > put_iova_domain(&domain->consistent_iovad); > vhost_iotlb_free(domain->iotlb); > vfree(domain->bounce_maps); > kfree(domain); > > return 0; > } > > This is quite a pain. I admit I don't have knowledge of this driver, and I don't > think it's safe to release two locks and then reacquire them. The situation is > rather complex. Therefore, I would prefer if the VDPA maintainers could > take the lead in implementing a proper fix. Would it be possible to move all that work to a deferred context? -- Michal Hocko SUSE Labs