In the iowait structure, two iowait_work entries were included to queue a given object: one for normal IB operations, and the other for TID RDMA operations. For non-TID RDMA operations, the iowait_work structure for TID RDMA is initialized to contain a NULL function (not used). When the QP is reset, the function iowait_cancel_work will be called to cancel any pending work. The problem is that this function will call cancel_work_sync() for both iowait_work entries, even though the one for TID RDMA is not used at all. Eventually, the call cascades to __flush_work(), wherein a WARN_ON will be triggered due to the fact that work->func is NULL. The WARN_ON was introduced in commit 4d43d395fed1 ("workqueue: Try to catch flush_work() without INIT_WORK().") This patch fixes the issue by making sure that a work function is present for TID RDMA before calling cancel_work_sync in iowait_cancel_work. Fixes: 4d43d395fed1 ("workqueue: Try to catch flush_work() without INIT_WORK().") Fixes: 5da0fc9dbf89 ("IB/hfi1: Prepare resource waits for dual leg") Link: https://lore.kernel.org/r/20191219211941.58387.39883.stgit@awfm-01.aw.intel.com Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com> Signed-off-by: Kaike Wan <kaike.wan@intel.com> Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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