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 00F54C433F5 for ; Tue, 23 Nov 2021 13:20:13 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5C8176B0071; Tue, 23 Nov 2021 08:19:58 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 54FF56B0072; Tue, 23 Nov 2021 08:19:58 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3F0C56B0073; Tue, 23 Nov 2021 08:19:58 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 283A36B0071 for ; Tue, 23 Nov 2021 08:19:58 -0500 (EST) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id C7F9F743E9 for ; Tue, 23 Nov 2021 13:19:47 +0000 (UTC) X-FDA: 78840252414.08.2E07168 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf10.hostedemail.com (Postfix) with ESMTP id 0366C6001AA0 for ; Tue, 23 Nov 2021 13:19:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=r8Lcq3ciu3667/Au2jyAismeBvkNUg7x0FQx5wyUwZU=; b=D0kvGtgoq1mzIow25vCHqjNTzR rlcpRav/4ALzGsUNMgD4ji4Xpq9njQEmbx58zzVxlcb8aNiF3yN6v/cv2niKpYnn5Z1vvcrkmp0gm a/1WusN7LOg2JkVCwzINcKuWzmOGBkmPToF9oleSyWcRo/zLF3lJvkmN2gduo+I5lmnlO95X8RjND +lcwHzwZeD3C6Pan57egRd8EnmtRg5dpLYP3pQBulohByzT7zQfhUthRRV2yu7ljN+umwgpMwwruB wgY+t/WKXKeUJa43hrOi7AnoKN87UbEcbYNOORxZv+qngwijtyL1+WM3//ovWsKHqvpV1Qj6ZRjKP UXyNFQVg==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mpVhn-00EumM-GD; Tue, 23 Nov 2021 13:19:27 +0000 Date: Tue, 23 Nov 2021 13:19:27 +0000 From: Matthew Wilcox To: Suren Baghdasaryan Cc: akpm@linux-foundation.org, mhocko@kernel.org, mhocko@suse.com, rientjes@google.com, hannes@cmpxchg.org, guro@fb.com, riel@surriel.com, minchan@kernel.org, kirill@shutemov.name, aarcange@redhat.com, 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 Subject: Re: [PATCH 1/2] mm: protect free_pgtables with mmap_lock write lock in exit_mmap Message-ID: References: <20211116215715.645231-1-surenb@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211116215715.645231-1-surenb@google.com> X-Rspamd-Queue-Id: 0366C6001AA0 X-Stat-Signature: a4hhdrsw1kwudpw5dj9iz3jptmkj1i5x Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=D0kvGtgo; dmarc=none; spf=none (imf10.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org X-Rspamd-Server: rspam02 X-HE-Tag: 1637673583-839957 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 Tue, Nov 16, 2021 at 01:57:14PM -0800, Suren Baghdasaryan wrote: > @@ -3170,6 +3172,7 @@ void exit_mmap(struct mm_struct *mm) > unmap_vmas(&tlb, vma, 0, -1); > free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, USER_PGTABLES_CEILING); > tlb_finish_mmu(&tlb); > + mmap_write_unlock(mm); > > /* > * Walk the list again, actually closing and freeing it, Is there a reason to unlock here instead of after the remove_vma loop? We'll need the mmap sem held during that loop when VMAs are stored in the maple tree.