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authorXin Long <lucien.xin@gmail.com>2021-05-17 02:28:58 +0800
committerDavid S. Miller <davem@davemloft.net>2021-05-17 14:07:48 -0700
commit04c26faa51d1e2fe71cf13c45791f5174c37f986 (patch)
tree45ba53c872e4ed678b25418d0c509f72b25c9a5c /net/tipc
parent020ef930b826d21c5446fdc9db80fd72a791bc21 (diff)
tipc: wait and exit until all work queues are done
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>
Diffstat (limited to 'net/tipc')
-rw-r--r--net/tipc/core.c2
-rw-r--r--net/tipc/core.h2
-rw-r--r--net/tipc/udp_media.c2
3 files changed, 6 insertions, 0 deletions
diff --git a/net/tipc/core.c b/net/tipc/core.c
index 5cc1f0307215..72f3ac73779b 100644
--- a/net/tipc/core.c
+++ b/net/tipc/core.c
@@ -119,6 +119,8 @@ static void __net_exit tipc_exit_net(struct net *net)
#ifdef CONFIG_TIPC_CRYPTO
tipc_crypto_stop(&tipc_net(net)->crypto_tx);
#endif
+ while (atomic_read(&tn->wq_count))
+ cond_resched();
}
static void __net_exit tipc_pernet_pre_exit(struct net *net)
diff --git a/net/tipc/core.h b/net/tipc/core.h
index 03de7b213f55..5741ae488bb5 100644
--- a/net/tipc/core.h
+++ b/net/tipc/core.h
@@ -149,6 +149,8 @@ struct tipc_net {
#endif
/* 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 e556d2cdc064..c2bb818704c8 100644
--- a/net/tipc/udp_media.c
+++ b/net/tipc/udp_media.c
@@ -814,6 +814,7 @@ 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();
@@ -834,6 +835,7 @@ 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);
}