[PATCH net 1/2] net/smc: initialize close_work early to avoid warning

Wen Gu
2024-11-22T07:22:05Z

We encountered a warning that close_work was canceled before
initialization.

WARNING: CPU: 7 PID: 111103 at kernel/workqueue.c:3047 __flush_work+0x19e/0x1b0
Workqueue: events smc_lgr_terminate_work [smc]
RIP: 0010:__flush_work+0x19e/0x1b0
Call Trace:
? __wake_up_common+0x7a/0x190
? work_busy+0x80/0x80
__cancel_work_timer+0xe3/0x160
smc_close_cancel_work+0x1a/0x70 [smc]
smc_close_active_abort+0x207/0x360 [smc]
__smc_lgr_terminate.part.38+0xc8/0x180 [smc]
process_one_work+0x19e/0x340
worker_thread+0x30/0x370
? process_one_work+0x340/0x340
kthread+0x117/0x130
? __kthread_cancel_work+0x50/0x50
ret_from_fork+0x22/0x30

This is because when smc_close_cancel_work is triggered, e.g. the RDMA
driver is rmmod and the LGR is terminated, the conn->close_work is
flushed before initialization, resulting in WARN_ON(!work->func).

__smc_lgr_terminate | smc_connect_{rdma|ism}
-------------------------------------------------------------
| smc_conn_create
| \- smc_lgr_register_conn
for conn in lgr->conns_all |
\- smc_conn_kill |
\- smc_close_active_abort |
\- smc_close_cancel_work |
\- cancel_work_sync |
\- __flush_work |
(close_work) |
| smc_close_init
| \- INIT_WORK(&close_work)

So fix this by initializing close_work before establishing the
connection.

Fixes: 46c28dbd4c23 ("net/smc: no socket state changes in tasklet context")
Fixes: 413498440e30 ("net/smc: add SMC-D support in af_smc")
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
---
net/smc/af_smc.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 9d76e902fd77..ed6d4d520bc7 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -383,6 +383,7 @@ void smc_sk_init(struct net *net, struct sock *sk, int protocol)
smc->limit_smc_hs = net->smc.limit_smc_hs;
smc->use_fallback = false; /* assume rdma capability first */
smc->fallback_rsn = 0;
+ smc_close_init(smc);
}

static struct sock *smc_sock_alloc(struct net *net, struct socket *sock,
@@ -1299,7 +1300,6 @@ static int smc_connect_rdma(struct smc_sock *smc,
goto connect_abort;
}

- smc_close_init(smc);
smc_rx_init(smc);

if (ini->first_contact_local) {
@@ -1435,7 +1435,6 @@ static int smc_connect_ism(struct smc_sock *smc,
goto connect_abort;
}
}
- smc_close_init(smc);
smc_rx_init(smc);
smc_tx_init(smc);

@@ -2479,7 +2478,6 @@ static void smc_listen_work(struct work_struct *work)
goto out_decl;

mutex_lock(&smc_server_lgr_pending);
- smc_close_init(new_smc);
smc_rx_init(new_smc);
smc_tx_init(new_smc);

--
2.32.0.3.g01195cf9f