From patchwork Thu Nov 10 13:01:59 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiubo Li X-Patchwork-Id: 624862 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 1A11FC433FE for ; Thu, 10 Nov 2022 13:03:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230107AbiKJNDN (ORCPT ); Thu, 10 Nov 2022 08:03:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57246 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229997AbiKJNDM (ORCPT ); Thu, 10 Nov 2022 08:03:12 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A5860725DC for ; Thu, 10 Nov 2022 05:02:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1668085330; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=u5HjnKAZTuzuiB1xXFf+3hVgIaNkF6QfHUMfW827l9M=; b=YE8bISW/fbLpxDeSgTp+NBhkbEGc1khnbfpZmJ3hWTQpTFs4kDrEnW3ySayDrpYlgLWWEo HuliYZEgk+zsAGVxJxHoWOTvKa/p+UC6t8cyA/BUxy3NOc3bT2zJWvuYnPTVmbBVgJlD0f Vl6SrUvXQ0ismHHFlDESObXKtcaMuW8= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-426-jq38i8FIOLyPnDUIDmwueA-1; Thu, 10 Nov 2022 08:02:07 -0500 X-MC-Unique: jq38i8FIOLyPnDUIDmwueA-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 9BFC51C09CA2; Thu, 10 Nov 2022 13:02:05 +0000 (UTC) Received: from lxbceph1.gsslab.pek2.redhat.com (unknown [10.72.47.117]) by smtp.corp.redhat.com (Postfix) with ESMTP id BA3D54A9256; Thu, 10 Nov 2022 13:02:02 +0000 (UTC) From: xiubli@redhat.com To: ceph-devel@vger.kernel.org, idryomov@gmail.com Cc: lhenriques@suse.de, jlayton@kernel.org, mchangir@redhat.com, Xiubo Li , stable@vger.kernel.org Subject: [PATCH v5] ceph: fix NULL pointer dereference for req->r_session Date: Thu, 10 Nov 2022 21:01:59 +0800 Message-Id: <20221110130159.33319-1-xiubli@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org From: Xiubo Li The request's r_session maybe changed when it was forwarded or resent. Both the forwarding and resending cases the requests will be protected by the mdsc->mutex. Cc: stable@vger.kernel.org URL: https://bugzilla.redhat.com/show_bug.cgi?id=2137955 Signed-off-by: Xiubo Li --- Changed in V5: - simplify the code by removing the "unlikely(s->s_mds >= max_sessions)" check. Changed in V4: - move mdsc->mutex acquisition and max_sessions assignment into "if (req1 || req2)" branch fs/ceph/caps.c | 48 ++++++++++++------------------------------------ 1 file changed, 12 insertions(+), 36 deletions(-) diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c index 894adfb4a092..065e9311b607 100644 --- a/fs/ceph/caps.c +++ b/fs/ceph/caps.c @@ -2297,7 +2297,6 @@ static int flush_mdlog_and_wait_inode_unsafe_requests(struct inode *inode) struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc; struct ceph_inode_info *ci = ceph_inode(inode); struct ceph_mds_request *req1 = NULL, *req2 = NULL; - unsigned int max_sessions; int ret, err = 0; spin_lock(&ci->i_unsafe_lock); @@ -2315,28 +2314,24 @@ static int flush_mdlog_and_wait_inode_unsafe_requests(struct inode *inode) } spin_unlock(&ci->i_unsafe_lock); - /* - * The mdsc->max_sessions is unlikely to be changed - * mostly, here we will retry it by reallocating the - * sessions array memory to get rid of the mdsc->mutex - * lock. - */ -retry: - max_sessions = mdsc->max_sessions; - /* * Trigger to flush the journal logs in all the relevant MDSes * manually, or in the worst case we must wait at most 5 seconds * to wait the journal logs to be flushed by the MDSes periodically. */ - if ((req1 || req2) && likely(max_sessions)) { - struct ceph_mds_session **sessions = NULL; - struct ceph_mds_session *s; + if (req1 || req2) { struct ceph_mds_request *req; + struct ceph_mds_session **sessions; + struct ceph_mds_session *s; + unsigned int max_sessions; int i; + mutex_lock(&mdsc->mutex); + max_sessions = mdsc->max_sessions; + sessions = kcalloc(max_sessions, sizeof(s), GFP_KERNEL); if (!sessions) { + mutex_unlock(&mdsc->mutex); err = -ENOMEM; goto out; } @@ -2348,16 +2343,6 @@ static int flush_mdlog_and_wait_inode_unsafe_requests(struct inode *inode) s = req->r_session; if (!s) continue; - if (unlikely(s->s_mds >= max_sessions)) { - spin_unlock(&ci->i_unsafe_lock); - for (i = 0; i < max_sessions; i++) { - s = sessions[i]; - if (s) - ceph_put_mds_session(s); - } - kfree(sessions); - goto retry; - } if (!sessions[s->s_mds]) { s = ceph_get_mds_session(s); sessions[s->s_mds] = s; @@ -2370,16 +2355,6 @@ static int flush_mdlog_and_wait_inode_unsafe_requests(struct inode *inode) s = req->r_session; if (!s) continue; - if (unlikely(s->s_mds >= max_sessions)) { - spin_unlock(&ci->i_unsafe_lock); - for (i = 0; i < max_sessions; i++) { - s = sessions[i]; - if (s) - ceph_put_mds_session(s); - } - kfree(sessions); - goto retry; - } if (!sessions[s->s_mds]) { s = ceph_get_mds_session(s); sessions[s->s_mds] = s; @@ -2391,11 +2366,12 @@ static int flush_mdlog_and_wait_inode_unsafe_requests(struct inode *inode) /* the auth MDS */ spin_lock(&ci->i_ceph_lock); if (ci->i_auth_cap) { - s = ci->i_auth_cap->session; - if (!sessions[s->s_mds]) - sessions[s->s_mds] = ceph_get_mds_session(s); + s = ci->i_auth_cap->session; + if (!sessions[s->s_mds]) + sessions[s->s_mds] = ceph_get_mds_session(s); } spin_unlock(&ci->i_ceph_lock); + mutex_unlock(&mdsc->mutex); /* send flush mdlog request to MDSes */ for (i = 0; i < max_sessions; i++) {