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 42E0EC433EF for ; Fri, 18 Feb 2022 08:10:59 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id AEDB86B0074; Fri, 18 Feb 2022 03:10:58 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id A9D3A6B0075; Fri, 18 Feb 2022 03:10:58 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 93E516B0078; Fri, 18 Feb 2022 03:10:58 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0131.hostedemail.com [216.40.44.131]) by kanga.kvack.org (Postfix) with ESMTP id 86B4C6B0074 for ; Fri, 18 Feb 2022 03:10:58 -0500 (EST) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 3E97795B1B for ; Fri, 18 Feb 2022 08:10:58 +0000 (UTC) X-FDA: 79155179796.28.CE001BE Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by imf15.hostedemail.com (Postfix) with ESMTP id 9B753A0003 for ; Fri, 18 Feb 2022 08:10:57 +0000 (UTC) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id 53E8E210F6; Fri, 18 Feb 2022 08:10:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1645171856; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=b/1wewcLt9nI8yFjnz0wjFrOsRJHDTJ8Yv+8E7hf14A=; b=odGXEz4xNqnCt1Css2BrJWqduFjaN9L8hcfjS0FasFnCsXfVpsam/kgpDs6zkaVJSLoOoa 1uoWYV59N602EF3j7y9z+fx65+lPyuUsdH2+x2iKUNe4C44UZgHGvHWfWNmq8oVmsAsHjJ BWaxOrpiep2LnmsGE4TQjC0vOJ613uU= Received: from suse.cz (unknown [10.100.201.86]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id D10D5A3B81; Fri, 18 Feb 2022 08:10:55 +0000 (UTC) Date: Fri, 18 Feb 2022 09:10:54 +0100 From: Michal Hocko To: Suren Baghdasaryan Cc: akpm@linux-foundation.org, shy828301@gmail.com, rientjes@google.com, willy@infradead.org, hannes@cmpxchg.org, guro@fb.com, riel@surriel.com, minchan@kernel.org, kirill@shutemov.name, aarcange@redhat.com, brauner@kernel.org, christian@brauner.io, hch@infradead.org, oleg@redhat.com, david@redhat.com, jannh@google.com, shakeelb@google.com, luto@kernel.org, christian.brauner@ubuntu.com, fweimer@redhat.com, jengelh@inai.de, timmurray@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@android.com, syzbot+2ccf63a4bd07cf39cab0@syzkaller.appspotmail.com Subject: Re: [PATCH 1/1] mm: fix use-after-free bug when mm->mmap is reused after being freed Message-ID: References: <20220215201922.1908156-1-surenb@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=odGXEz4x; dmarc=pass (policy=quarantine) header.from=suse.com; spf=pass (imf15.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.28 as permitted sender) smtp.mailfrom=mhocko@suse.com X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 9B753A0003 X-Stat-Signature: owxsspzo3ymm1cktc37weup9grfry57r X-HE-Tag: 1645171857-927753 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: On Thu 17-02-22 11:51:13, Suren Baghdasaryan wrote: > On Tue, Feb 15, 2022 at 11:54 PM Michal Hocko wrote: [...] > > I really have to say that I hate how complex this has grown in the name > > of optimizations. This has backfired several times already resulting in > > 2 security issues. I really hope to get read any note of the oom reaper > > from exit_mmap. > > Agree. I want to take another stab at removing __oom_reap_task_mm from > exit_mmap. Now that Hugh made changes to mlock mechanisms and > __oom_reap_task_mm does not skip locked vmas I think that should be > possible. Planning to look into that sometimes next week. Thanks! -- Michal Hocko SUSE Labs