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commit2ee9bf346fupstream. This three thread race can result in the work being run once the callback becomes NULL: CPU1 CPU2 CPU3 netevent_callback() process_one_req() rdma_addr_cancel() [..] spin_lock_bh() set_timeout() spin_unlock_bh() spin_lock_bh() list_del_init(&req->list); spin_unlock_bh() req->callback = NULL spin_lock_bh() if (!list_empty(&req->list)) // Skipped! // cancel_delayed_work(&req->work); spin_unlock_bh() process_one_req() // again req->callback() // BOOM cancel_delayed_work_sync() The solution is to always cancel the work once it is completed so any in between set_timeout() does not result in it running again. Cc: stable@vger.kernel.org Fixes:44e75052bc("RDMA/rdma_cm: Make rdma_addr_cancel into a fence") Link: https://lore.kernel.org/r/20200930072007.1009692-1-leon@kernel.org Reported-by: Dan Aloni <dan@kernelim.com> Signed-off-by: Leon Romanovsky <leonro@nvidia.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>