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 5C35AECAAD8 for ; Fri, 16 Sep 2022 08:38:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B5B078D0002; Fri, 16 Sep 2022 04:38:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AE3898D0001; Fri, 16 Sep 2022 04:38:38 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 95CFE8D0002; Fri, 16 Sep 2022 04:38:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 7FEB68D0001 for ; Fri, 16 Sep 2022 04:38:38 -0400 (EDT) Received: from smtpin29.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 43D99160798 for ; Fri, 16 Sep 2022 08:38:38 +0000 (UTC) X-FDA: 79917297516.29.0B8C8D4 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf09.hostedemail.com (Postfix) with ESMTP id EDE6A1400B7 for ; Fri, 16 Sep 2022 08:38:36 +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=7fHPa+fZWPQwBlSldGIrGAzienq3Hs2skinlakk4KaM=; b=AoOeeScgRUfA5iXdFP9LGk4wYC GQsyBuoArOEbEHcsKz+B0F5IhFoOAKk2wDKzWUHPcXP9S4E5+jlprhLFYmNRACHaJsBIKtKvF1moZ SASxLuAhJYLemLpIIVCseUXFz8c8eSkF9WzA2QMO5QzPAREEbDmCCLVQmOqAhyiMFwCwGy+YMDtH8 8hkXAm8IB24iKUCWBHpFwey0qKv1mChhZTqZRLHuP9ZVksUKPLtsf/v3ey+03AQYTReZztBxWpRHY NBabhnzr5/DHRRie1FDAfziaxF1vo2BQd9eyLi/VEGejkJIPbqiQGl0hyvuHlZklUa+pBwIo5xq72 SEDLtPhQ==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1oZ6rp-0021zg-CR; Fri, 16 Sep 2022 08:38:33 +0000 Date: Fri, 16 Sep 2022 09:38:33 +0100 From: Matthew Wilcox To: Yu Zhao Cc: Andrew Morton , dev@der-flo.net, Linux-MM , Uladzislau Rezki , bugzilla-daemon@kernel.org, Kees Cook Subject: Re: [Bug 216489] New: Machine freezes due to memory lock Message-ID: References: <20220915133931.ee0a6c8a86c59a144828eb60@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=AoOeeScg; spf=none (imf09.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-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1663317517; a=rsa-sha256; cv=none; b=N43ZQrmOQ/+SHn/I7cz7Q0w3I3rM2pf6InvQKipdnfoDcFBg+Eul25GLQVtzARBX/1p7bM B/emucmoDNhd0/3LcZEqIuOLczvW8NgK2tMzWEuRx/zFzOrF5AGK3A+v9oJcY2WBHIUD0M ydcxO8ad0W0/vlrLZv1s5subCYfVqqc= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1663317517; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=7fHPa+fZWPQwBlSldGIrGAzienq3Hs2skinlakk4KaM=; b=IFasiPDfjdcF8W1BDW23Lh1pU3CLYjMhLsGCsv21fZS4AyGio6pqxxzoRadkGa0wPoqQRf stutcDhTlNjoNuo5GUgwKcn/NF4QIaniQNH6oWT1uEcah0NQO8xCsgYyU80FlrTBpGJsAP x5MSuSQQqPZ56dwtHkJ/JOn2z0g8QcM= X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: EDE6A1400B7 Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=AoOeeScg; spf=none (imf09.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none X-Stat-Signature: 3p5kmjg5oxjirhw1usdhugrredhu3wwq X-HE-Tag: 1663317516-985486 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, Sep 15, 2022 at 05:59:56PM -0600, Yu Zhao wrote: > I think this is a manifest of the lockdep warning I reported a couple > of weeks ago: > https://lore.kernel.org/r/CAOUHufaPshtKrTWOz7T7QFYUNVGFm0JBjvM700Nhf9qEL9b3EQ@mail.gmail.com/ That would certainly match the symptoms. Turning vmap_lock into an NMI-safe lock would be bad. I don't even know if we have primitives for that (it's not like you can disable an NMI ...) I don't quite have time to write a patch right now. Perhaps something like: struct vmap_area *find_vmap_area_nmi(unsigned long addr) { struct vmap_area *va; if (spin_trylock(&vmap_area_lock)) return NULL; va = __find_vmap_area(addr, &vmap_area_root); spin_unlock(&vmap_area_lock); return va; } and then call find_vmap_area_nmi() in check_heap_object(). I may have the polarity of the return value of spin_trylock() incorrect.