fdc1416c21
commit d966ddcc38217a6110a6a0ff37ad2dee7d42e23e upstream.
In the commit fdeba99b1e58
("tipc: fix use-after-free in tipc_bcast_get_mode"), we're trying
to make sure the tipc_net_finalize_work work item finished if it
enqueued. But calling flush_scheduled_work() is not just affecting
above work item but either any scheduled work. This has turned out
to be overkill and caused to deadlock as syzbot reported:
======================================================
WARNING: possible circular locking dependency detected
5.9.0-rc2-next-20200828-syzkaller #0 Not tainted
------------------------------------------------------
kworker/u4:6/349 is trying to acquire lock:
ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: flush_workqueue+0xe1/0x13e0 kernel/workqueue.c:2777
but task is already holding lock:
ffffffff8a879430 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9b/0xb10 net/core/net_namespace.c:565
[...]
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(pernet_ops_rwsem);
lock(&sb->s_type->i_mutex_key#13);
lock(pernet_ops_rwsem);
lock((wq_completion)events);
*** DEADLOCK ***
[...]
v1:
To fix the original issue, we replace above calling by introducing
a bit flag. When a namespace cleaned-up, bit flag is set to zero and:
- tipc_net_finalize functionial just does return immediately.
- tipc_net_finalize_work does not enqueue into the scheduled work queue.
v2:
Use cancel_work_sync() helper to make sure ONLY the
tipc_net_finalize_work() stopped before releasing bcbase object.
Reported-by: syzbot+d5aa7e0385f6a5d0f4fd@syzkaller.appspotmail.com
Fixes: fdeba99b1e58 ("tipc: fix use-after-free in tipc_bcast_get_mode")
Acked-by: Jon Maloy <jmaloy@redhat.com>
Signed-off-by: Hoang Huu Le <hoang.h.le@dektech.com.au>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
53 lines
2.4 KiB
C
53 lines
2.4 KiB
C
/*
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* net/tipc/net.h: Include file for TIPC network routing code
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*
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* Copyright (c) 1995-2006, 2014, Ericsson AB
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* Copyright (c) 2005, 2010-2011, Wind River Systems
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the names of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* Alternatively, this software may be distributed under the terms of the
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* GNU General Public License ("GPL") version 2 as published by the Free
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* Software Foundation.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef _TIPC_NET_H
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#define _TIPC_NET_H
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#include <net/genetlink.h>
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extern const struct nla_policy tipc_nl_net_policy[];
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int tipc_net_init(struct net *net, u8 *node_id, u32 addr);
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void tipc_net_finalize_work(struct work_struct *work);
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void tipc_sched_net_finalize(struct net *net, u32 addr);
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void tipc_net_stop(struct net *net);
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int tipc_nl_net_dump(struct sk_buff *skb, struct netlink_callback *cb);
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int tipc_nl_net_set(struct sk_buff *skb, struct genl_info *info);
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int __tipc_nl_net_set(struct sk_buff *skb, struct genl_info *info);
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#endif
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