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Subject: Re: [PATCH] infiniband: core: mad: Fix a sleep-in-atomic-context bug
 in ib_mad_recv_done()
To:     Jason Gunthorpe <jgg@ziepe.ca>
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
References: <20180901120659.32509-1-baijiaju1990@gmail.com>
 <20180902203229.GA13946@ziepe.ca>
From:   Jia-Ju Bai <baijiaju1990@gmail.com>
Message-ID: <c8aef2dd-5fa7-f619-d6ce-8b67087ed738@gmail.com>
Date:   Mon, 3 Sep 2018 09:41:06 +0800
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On 2018/9/3 4:32, Jason Gunthorpe wrote:
> 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.

Okay, sorry for this false positive.


Best wishes,
Jia-Ju Bai