diff options
| author | Xin Long <lucien.xin@gmail.com> | 2021-05-17 02:28:58 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-06-03 08:59:07 +0200 |
| commit | d1f76dfadaf8f47ed1753f97dbcbd41c16215ffa (patch) | |
| tree | 88fc07c6e871fed88df745766b98f179ee406563 /net/tipc | |
| parent | bdd37028a026a3cb93a0ff8486cbaad553109d8e (diff) | |
tipc: wait and exit until all work queues are done
commit 04c26faa51d1e2fe71cf13c45791f5174c37f986 upstream.
On some host, a crash could be triggered simply by repeating these
commands several times:
# modprobe tipc
# tipc bearer enable media udp name UDP1 localip 127.0.0.1
# rmmod tipc
[] BUG: unable to handle kernel paging request at ffffffffc096bb00
[] Workqueue: events 0xffffffffc096bb00
[] Call Trace:
[] ? process_one_work+0x1a7/0x360
[] ? worker_thread+0x30/0x390
[] ? create_worker+0x1a0/0x1a0
[] ? kthread+0x116/0x130
[] ? kthread_flush_work_fn+0x10/0x10
[] ? ret_from_fork+0x35/0x40
When removing the TIPC module, the UDP tunnel sock will be delayed to
release in a work queue as sock_release() can't be done in rtnl_lock().
If the work queue is schedule to run after the TIPC module is removed,
kernel will crash as the work queue function cleanup_beareri() code no
longer exists when trying to invoke it.
To fix it, this patch introduce a member wq_count in tipc_net to track
the numbers of work queues in schedule, and wait and exit until all
work queues are done in tipc_exit_net().
Fixes: d0f91938bede ("tipc: add ip/udp media type")
Reported-by: Shuang Li <shuali@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Jon Maloy <jmaloy@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/tipc')
| -rw-r--r-- | net/tipc/core.c | 3 | ||||
| -rw-r--r-- | net/tipc/core.h | 2 | ||||
| -rw-r--r-- | net/tipc/udp_media.c | 2 |
3 files changed, 7 insertions, 0 deletions
diff --git a/net/tipc/core.c b/net/tipc/core.c index e3d79f8b69d8..90cf7e0bbaf0 100644 --- a/net/tipc/core.c +++ b/net/tipc/core.c @@ -107,6 +107,9 @@ static void __net_exit tipc_exit_net(struct net *net) tipc_bcast_stop(net); tipc_nametbl_stop(net); tipc_sk_rht_destroy(net); + + while (atomic_read(&tn->wq_count)) + cond_resched(); } static struct pernet_operations tipc_net_ops = { diff --git a/net/tipc/core.h b/net/tipc/core.h index e119c4a88d63..c6bda91f8581 100644 --- a/net/tipc/core.h +++ b/net/tipc/core.h @@ -143,6 +143,8 @@ struct tipc_net { /* Work item for net finalize */ struct tipc_net_work final_work; + /* The numbers of work queues in schedule */ + atomic_t wq_count; }; static inline struct tipc_net *tipc_net(struct net *net) diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c index 8f0977a9d423..1fb0535e2eb4 100644 --- a/net/tipc/udp_media.c +++ b/net/tipc/udp_media.c @@ -802,6 +802,7 @@ static void cleanup_bearer(struct work_struct *work) kfree_rcu(rcast, rcu); } + atomic_dec(&tipc_net(sock_net(ub->ubsock->sk))->wq_count); dst_cache_destroy(&ub->rcast.dst_cache); udp_tunnel_sock_release(ub->ubsock); synchronize_net(); @@ -822,6 +823,7 @@ static void tipc_udp_disable(struct tipc_bearer *b) RCU_INIT_POINTER(ub->bearer, NULL); /* sock_release need to be done outside of rtnl lock */ + atomic_inc(&tipc_net(sock_net(ub->ubsock->sk))->wq_count); INIT_WORK(&ub->work, cleanup_bearer); schedule_work(&ub->work); } |