diff options
author | Duoming Zhou <duoming@zju.edu.cn> | 2022-04-18 18:33:22 +0300 |
---|---|---|
committer | Jason Gunthorpe <jgg@nvidia.com> | 2022-04-19 19:12:51 +0300 |
commit | 679ab61bf5f5f519377d812afb4fb93634782c74 (patch) | |
tree | ee8f00c3a5f3ef767cf3d91973f01e7db98ac172 /drivers/infiniband/hw/irdma | |
parent | 290c4a902b79246ec55e477fc313f27f98393dee (diff) | |
download | linux-679ab61bf5f5f519377d812afb4fb93634782c74.tar.xz |
RDMA/irdma: Fix deadlock in irdma_cleanup_cm_core()
There is a deadlock in irdma_cleanup_cm_core(), which is shown below:
(Thread 1) | (Thread 2)
| irdma_schedule_cm_timer()
irdma_cleanup_cm_core() | add_timer()
spin_lock_irqsave() //(1) | (wait a time)
... | irdma_cm_timer_tick()
del_timer_sync() | spin_lock_irqsave() //(2)
(wait timer to stop) | ...
We hold cm_core->ht_lock in position (1) of thread 1 and use
del_timer_sync() to wait timer to stop, but timer handler also need
cm_core->ht_lock in position (2) of thread 2. As a result,
irdma_cleanup_cm_core() will block forever.
This patch removes the check of timer_pending() in
irdma_cleanup_cm_core(), because the del_timer_sync() function will just
return directly if there isn't a pending timer. As a result, the lock is
redundant, because there is no resource it could protect.
Link: https://lore.kernel.org/r/20220418153322.42524-1-duoming@zju.edu.cn
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Reviewed-by: Shiraz Saleem <shiraz.saleem@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Diffstat (limited to 'drivers/infiniband/hw/irdma')
-rw-r--r-- | drivers/infiniband/hw/irdma/cm.c | 7 |
1 files changed, 1 insertions, 6 deletions
diff --git a/drivers/infiniband/hw/irdma/cm.c b/drivers/infiniband/hw/irdma/cm.c index dedb3b7edd8d..a98d962e5efb 100644 --- a/drivers/infiniband/hw/irdma/cm.c +++ b/drivers/infiniband/hw/irdma/cm.c @@ -3246,15 +3246,10 @@ int irdma_setup_cm_core(struct irdma_device *iwdev, u8 rdma_ver) */ void irdma_cleanup_cm_core(struct irdma_cm_core *cm_core) { - unsigned long flags; - if (!cm_core) return; - spin_lock_irqsave(&cm_core->ht_lock, flags); - if (timer_pending(&cm_core->tcp_timer)) - del_timer_sync(&cm_core->tcp_timer); - spin_unlock_irqrestore(&cm_core->ht_lock, flags); + del_timer_sync(&cm_core->tcp_timer); destroy_workqueue(cm_core->event_wq); cm_core->dev->ws_reset(&cm_core->iwdev->vsi); |