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

Wenjia Zhang
2024-11-22T15:56:36Z

On 22.11.24 08:16, Wen Gu wrote:
> 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>
> ---

It looks plausible to me. Thank you for fixing it!

Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>

Thanks,
Wenjia