Re: [PATCH rdma-rc] RDMA/cma: Fix hang when cma_netevent_callback fails to queue_work

[Jason Gunthorpe <jgg@nvidia.com>]

On Wed, May 21, 2025 at 02:36:02PM +0300, Leon Romanovsky wrote:
> From: Jack Morgenstein <jackm@nvidia.com>
> 
> The cited commit fixed a crash when cma_netevent_callback was called for
> a cma_id while work on that id from a previous call had not yet started.
> The work item was re-initialized in the second call, which corrupted the
> work item currently in the work queue.
> 
> However, it left a problem when queue_work fails (because the item is
> still pending in the work queue from a previous call). In this case,
> cma_id_put (which is called in the work handler) is therefore not
> called. This results in a userspace process hang (zombie process).
> 
> Fix this by calling cma_id_put() if queue_work fails.
> 
> Fixes: 45f5dcdd0497 ("RDMA/cma: Fix workqueue crash in cma_netevent_work_handler")
> Signed-off-by: Jack Morgenstein <jackm@nvidia.com>
> Signed-off-by: Feng Liu <feliu@nvidia.com>
> Reviewed-by: Vlad Dumitrescu <vdumitrescu@nvidia.com>
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> Reviewed-by: Sharath Srinivasan <sharath.srinivasan@oracle.com>
> Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
> ---
>  drivers/infiniband/core/cma.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)

Applied to for-next, thanks

Jason