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 7AEF2C4345F for ; Tue, 16 Apr 2024 04:35:59 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E00496B0083; Tue, 16 Apr 2024 00:35:58 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D894C6B0085; Tue, 16 Apr 2024 00:35:58 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C29996B0087; Tue, 16 Apr 2024 00:35:58 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id A30746B0083 for ; Tue, 16 Apr 2024 00:35:58 -0400 (EDT) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 1E3221A08EC for ; Tue, 16 Apr 2024 04:35:58 +0000 (UTC) X-FDA: 82014132396.14.83CC5CF Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf15.hostedemail.com (Postfix) with ESMTP id F3018A000D for ; Tue, 16 Apr 2024 04:35:55 +0000 (UTC) Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=dWZHFX+9; spf=none (imf15.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1713242156; 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=y4OQjG/SQObAypZdOJmY4oLcZqFzZ75jK2QHH/IhD6I=; b=BHLVP9uJ80SF7iS1NoySeJvbQiNEILp32NKBP/CuKdrBvTjLJdkiaC/AowneIS27VtDfXj cNpYIlIF/tW2/7/dINJBYZBYAIgC3Qus096Q4AA62gA9DSsNkfqgUIHuldlyAx5sdasuhr ueJsNo2PFNsB2Mpr8RkqJvb2xLBVzWY= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1713242156; a=rsa-sha256; cv=none; b=gBglJHeqJXb4p819fU+wmRnJ0xfr1ZjShg3403wzV+uTY/xvFzZ91ivCnuMA4S9gqWggCK Ol+TNsrl/zIqY7tPWbUbD/mK8S5iNSI7bEPKyrCOznV6Axn5XiMuSakyw8M66rL6eIy3n2 101JWyOFMuvO4ETT7Zv2xUPqfCoYxWM= ARC-Authentication-Results: i=1; imf15.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=dWZHFX+9; spf=none (imf15.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=y4OQjG/SQObAypZdOJmY4oLcZqFzZ75jK2QHH/IhD6I=; b=dWZHFX+9nkrpBo6cOqeNwr/T4n sOBtxyh8FEbubvkmTZgBr6/vA9tGQiFanRwgth+sOeXonRCq4QfGvgrCy/0qpOQKsqJIowfypJ/Ae rgIxh9n6zPup9xadU4Jvz6eRe6MR6VrASk5fbilYhTVOdRAfAr8yXO8gA80OZ+bvOk3UdowvBUmrB jjlrja4LlipBzMN3yYufhNDsW9ICmnNqIBk34nANY5yvb2wK6BeoHkcw0xdIMIvWEM34a1gvloFWu FbavR9iTCatx/3s7N6XhjFmorIdgd56yRIFOzn8JA5ruLm3eDT8f1cJdN32he9F8v9NPuQXafIAA1 /vuIDmDA==; Received: from willy by casper.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1rwaXu-0000000HETq-2Pis; Tue, 16 Apr 2024 04:35:50 +0000 Date: Tue, 16 Apr 2024 05:35:50 +0100 From: Matthew Wilcox To: Vishal Moola Cc: syzbot , akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, muchun.song@linux.dev, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [mm?] KASAN: slab-use-after-free Read in __vma_reservation_common Message-ID: References: <000000000000daf1e10615e64dcb@google.com> <000000000000ae5d410615fea3bf@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Rspamd-Queue-Id: F3018A000D X-Rspam-User: X-Stat-Signature: pwgowogngmmqouot3dmp3ju61tr9mezt X-Rspamd-Server: rspam03 X-HE-Tag: 1713242155-416067 X-HE-Meta: U2FsdGVkX18pk12vj6UQdmJvn2UpUfhZIhCZsCs3PCxx4Q36RdiFDIIndZ671RKh43xmn6nBIogpHT6CHvRnqOpF29xSfZmKiOIpDKg6MbIdYp/X9Ni9HtM64mN0BWMXSnK2Cai7lhUBewn/yQf2BAzV8M4tabKGauGap5Vn4wf4ACYvx5YIq+PecvKWXJOsPlazxID04Wl8g5hHdiRN9aqacij5gZe7p+0W4VJuGgcnCvPPwdkvwDnDMzn8fZ/4zRKNQaZQM5Op1kmJ+DJw/5snBHGBx+ieHPmyaE3yzbyy3d0dduPqYNP1GZOZBrncJDmf8VyjpoJSvF8aFFBkzoKtKJ4WcsDg8zir23NKo94rY/xPr/VRMQWJLHvnZqdhPJIsVm1alc3vOuj8qmrAfraSUSDsYYk0zq2N81b8OYM15BEXr8DmKGOTBLjJXkDV++kOM471LHtfVt5rsootFR5Dd+n9NXlE3ynJvc3XI2M7+X5gK2D9rnmAJA92UqQ3sxZs486s5m/gdTZcr8+GKUem350Z82a8MozSx5a3TBxQKlAxW4+6NtlKG5y9rWNJOAjwAzyZURxauPMXrHj6ZkyL1OnXYqvWEJdma4Y9wUAWmOy3wURDP3z/ZAmfOCy9i7u0suiql4chduC+u3X5B8gTVsYqivHq76Jz0xLNIfmFQh84a8csRe6t61dV/aelvrdhyFPobQC+Q5zEavoZuBXCZPw2bl1z98L+LJQIjUyFiBHDpcIi2hFVZekIYHLPregWFmekUrYxJAandaDHboYAwtgYvLO9ya2o02A2zFTojFu+n7Pd4Qaf+osCB0Jo6YbLYV8lRkDUIQItPoTmNHhTLCTF7h/q62nWu+ZOQ3LyLsC6SEirs+78Ypjqq5zO0UR+SNVuKmwJ2P+vd0JK9Nd1MqNx0YvI1/Zg+mNSU27/NLDaLCEvHZ3mU0OFYWi5HzX3L7j26HkIXoHRIWn Avg6Lajt l54P1nI42I4IBICS/SmpS4bZcSi1CrXFY+niO2T+l9ziB6UlFaLVZSgPp+QAHO5Nf1B1Ojs7Q9aLaMJNl69w/SYTJTvbnQ+sM/KXUqz+q8OwmskZ+tWSoiN3bwIAuP7N0Rc+bRDZsUjMo4480yyfUwzoBvwXiiUpVpRXFTMN0VVquhMmjLv9E9mArVMg4/c3/DJL/LmiQ7wxKlmk16BmPaa8ghnPQG7nKAd6t67f3Z/E4sLvwdZwPA8TUxP6GfVAO79Xn05wj1jCWkOlpj40WB2tm+F3iW7GHM+rT6IG8b0JpLSERCvGvmfKKkKUErPf44GANJI0/m2q6yA4ra26LVwK2NV+r3LvZ2mXRUFGDKMNO+ntBjCSKf5w8jJ69dm/grTbaexUIX49VJTFgUD7TH8hLAA== 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 Mon, Apr 15, 2024 at 04:02:48PM -0700, Vishal Moola wrote: > On Mon, Apr 15, 2024 at 3:15 PM Matthew Wilcox wrote: > > > > On Mon, Apr 15, 2024 at 03:05:44PM -0700, Vishal Moola wrote: > > > Commit 9acad7ba3e25 ("hugetlb: use vmf_anon_prepare() instead of > > > anon_vma_prepare()") may bailout after allocating a folio if we do not > > > hold the mmap lock. When this occurs, vmf_anon_prepare() will release the > > > vma lock. Hugetlb then attempts to call restore_reserve_on_error(), > > > which depends on the vma lock being held. > > > > > > We can move vmf_anon_prepare() prior to the folio allocation in order to > > > avoid calling restore_reserve_on_error() without the vma lock. > > > > But now you're calling vmf_anon_prepare() in the wrong place -- before > > we've determined that we need an anon folio. So we'll create an > > anon_vma even when we don't need one for this vma. > > That's true. Though that can be addressed through something like: > > if (!(vma->vm_flags & VM_MAYSHARE)) { > ret = vmf_anon_prepare(vmf); > if (unlikely(ret)) > goto out; > } Why does hugetlbfs use VM_MAYSHARE while regular faults use VM_SHARED?