On Mon, Apr 18, 2022 at 11:33:22PM +0800, Duoming Zhou wrote: > 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. > > Signed-off-by: Duoming Zhou <duoming@xxxxxxxxxx> > --- > Changes in V6: > - Change subject line prefixed with "RDMA/irdma: ". > > drivers/infiniband/hw/irdma/cm.c | 5 +---- > 1 file changed, 1 insertion(+), 4 deletions(-) I fixed the compile warning. Applied to for-rc, thanks Jason
