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[174.3.196.123]) by smtp.gmail.com with ESMTPSA id m15-v6sm28638567pfk.149.2018.09.02.13.32.29 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Sun, 02 Sep 2018 13:32:30 -0700 (PDT) Received: from jgg by mlx.ziepe.ca with local (Exim 4.90_1) (envelope-from ) id 1fwZ2r-0004TG-D1; Sun, 02 Sep 2018 14:32:29 -0600 Date: Sun, 2 Sep 2018 14:32:29 -0600 From: Jason Gunthorpe To: Jia-Ju Bai Cc: dledford@redhat.com, leon@kernel.org, ira.weiny@intel.com, pravin.shedge4linux@gmail.com, hal@mellanox.com, parav@mellanox.com, haakon.bugge@oracle.com, bart.vanassche@sandisk.com, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] infiniband: core: mad: Fix a sleep-in-atomic-context bug in ib_mad_recv_done() Message-ID: <20180902203229.GA13946@ziepe.ca> References: <20180901120659.32509-1-baijiaju1990@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180901120659.32509-1-baijiaju1990@gmail.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Sep 01, 2018 at 08:06:59PM +0800, Jia-Ju Bai wrote: > The driver may sleep with holding a spinlock. > > The function call paths (from bottom to top) in Linux-4.16 are: > > [FUNC] alloc_mad_private(GFP_KERNEL) > drivers/infiniband/core/mad.c, 2264: > alloc_mad_private in ib_mad_recv_done > drivers/infiniband/core/cq.c, 45: > [FUNC_PTR]ib_mad_recv_done in __ib_process_cq > drivers/infiniband/core/cq.c, 77: > __ib_process_cq in ib_process_cq_direct > drivers/infiniband/ulp/srp/ib_srp.c, 2010: > ib_process_cq_direct in __srp_get_tx_iu > drivers/infiniband/ulp/srp/ib_srp.c, 2353: > __srp_get_tx_iu in srp_queuecommand > drivers/infiniband/ulp/srp/ib_srp.c, 2352: > _raw_spin_lock_irqsave in srp_queuecommand > > [FUNC] alloc_mad_private(GFP_KERNEL) > drivers/infiniband/core/mad.c, 2264: > alloc_mad_private in ib_mad_recv_done > drivers/infiniband/core/cq.c, 45: > [FUNC_PTR]ib_mad_recv_done in __ib_process_cq > drivers/infiniband/core/cq.c, 77: > __ib_process_cq in ib_process_cq_direct This trace doesn't seem right, the CQ used by SRP will never have ib_mad_recv_done as a function pointer. Jason