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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 18278C4332F for ; Tue, 8 Nov 2022 02:25:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233029AbiKHCZS (ORCPT ); Mon, 7 Nov 2022 21:25:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53038 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232900AbiKHCZQ (ORCPT ); Mon, 7 Nov 2022 21:25:16 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 13B7E17AB8 for ; Mon, 7 Nov 2022 18:24:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1667874260; h=from:from: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; bh=7szDA3aJA2JeppTlYEmPkBUWEjAHUFnJ9ELoQFnSRV8=; b=SQPyDkfB46ZAXueXEm5Soy+iOQjm9Z5H2ACAp1wNCEkJeGWIUH1um9OdP2SEcc1hGBnzTd RhsBFBOQN6a+TUu1YkKAy1HB48kMkkLIkwp+Bf2yVXeCfo1bQCKNx3s5wH6PSi78yCUCEw nUD/n3QSNzlNiOal9TT7j38KzS5j46M= Received: from mail-pg1-f198.google.com (mail-pg1-f198.google.com [209.85.215.198]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-665-SixpAay7P2u_XOJy1cSbwQ-1; Mon, 07 Nov 2022 21:24:19 -0500 X-MC-Unique: SixpAay7P2u_XOJy1cSbwQ-1 Received: by mail-pg1-f198.google.com with SMTP id p18-20020a63e652000000b0046b27534651so7184464pgj.17 for ; Mon, 07 Nov 2022 18:24:19 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-language:content-transfer-encoding:in-reply-to:mime-version :user-agent:date:message-id:from:references:cc:to:subject :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=7szDA3aJA2JeppTlYEmPkBUWEjAHUFnJ9ELoQFnSRV8=; b=gg715UFxEa1twpQvyNLEJjAHur0fT82985OwTIkIRITgpcqp5FumHwCHa+31FDvGiN j1J0YDYXWo5lGaTve4tc1QrlVmfoa4X2LzU31aqYZBHR3Ci5RwH1OdiE311qHS4VIIfS SZt3l9lidun8xtJ81xf3XONMOUrDfH5iUHpuP9wexavqsUUJnfnBPskUGCmSO2tXBJS2 jHwLbDSB4CUV3pqf3Tc990ly8zWQAqNfD8N2XoTDeLJkr6KxBk1wtRnoH9Q2hAXX4axR MiuESl/vG/Rrx/8zZpinpcNqKeCT5Vxv6lfsGy2JFAs5KdRgj1Lld3iywzyBl5AdgsN4 qO2Q== X-Gm-Message-State: ACrzQf3XsGDHY1m6GjZPlxhp0Im64F+duFLFd4cyW8f8RsCSq/B5UiKz MWvYTEBtjtco2lDVCe++d1OQCb5e0WJA1z7lXlMZqOPmO4oQgIQ7X56xBGs4NmlsPqCSGtEhWBi u1hBr+HJjlXPKMxJePLN84Q== X-Received: by 2002:a63:2b41:0:b0:46e:9364:eb07 with SMTP id r62-20020a632b41000000b0046e9364eb07mr45892054pgr.46.1667874258360; Mon, 07 Nov 2022 18:24:18 -0800 (PST) X-Google-Smtp-Source: AMsMyM4Bcif+i8EW3zXFsuWf77/tbMGzhhakJk/4GRcDIQOMAwm0itgnnSv7a1F/Nkz0mcG6db/y6A== X-Received: by 2002:a63:2b41:0:b0:46e:9364:eb07 with SMTP id r62-20020a632b41000000b0046e9364eb07mr45892043pgr.46.1667874258106; Mon, 07 Nov 2022 18:24:18 -0800 (PST) Received: from [10.72.12.88] ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id h11-20020a170902f70b00b00182a9c27acfsm5616075plo.227.2022.11.07.18.24.13 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 07 Nov 2022 18:24:17 -0800 (PST) Subject: Re: [PATCH] ceph: avoid putting the realm twice when docoding snaps fails To: Ilya Dryomov Cc: ceph-devel@vger.kernel.org, lhenriques@suse.de, jlayton@kernel.org, mchangir@redhat.com, stable@vger.kernel.org References: <20221107071759.32000-1-xiubli@redhat.com> From: Xiubo Li Message-ID: Date: Tue, 8 Nov 2022 10:24:05 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org On 07/11/2022 23:21, Ilya Dryomov wrote: > On Mon, Nov 7, 2022 at 8:18 AM wrote: >> From: Xiubo Li >> >> When decoding the snaps fails it maybe leaving the 'first_realm' >> and 'realm' pointing to the same snaprealm memory. And then it'll >> put it twice and could cause random use-after-free, BUG_ON, etc >> issues. >> >> Cc: stable@vger.kernel.org >> URL: https://tracker.ceph.com/issues/57686 >> Signed-off-by: Xiubo Li >> --- >> fs/ceph/snap.c | 6 ++++-- >> 1 file changed, 4 insertions(+), 2 deletions(-) >> >> diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c >> index 9bceed2ebda3..baf17df05107 100644 >> --- a/fs/ceph/snap.c >> +++ b/fs/ceph/snap.c >> @@ -849,10 +849,12 @@ int ceph_update_snap_trace(struct ceph_mds_client *mdsc, >> if (realm_to_rebuild && p >= e) >> rebuild_snap_realms(realm_to_rebuild, &dirty_realms); >> >> - if (!first_realm) >> + if (!first_realm) { >> first_realm = realm; >> - else >> + realm = NULL; > Hi Xiubo, > > I wonder why realm is cleared only in !first_realm branch? Can't > the same issue occur with realm? > > first_realm is already set, ceph_put_snap_realm(realm) > p < e, goto more > decoding fails, goto bad > realm is still set and not IS_ERR, ceph_put_snap_realm(realm) > Yeah, makes sense. I will fix this. Thanks Ilya! > > Thanks, > > Ilya >