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Subject: Re: [PATCH] nvme-rdma: fix double free in nvme_rdma_free_queue
To:     Christoph Hellwig <hch@lst.de>
Cc:     keith.busch@intel.com, axboe@fb.com, sagi@grimberg.me,
        linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org
References: <1525420938-9492-1-git-send-email-jianchao.w.wang@oracle.com>
 <20180507122736.GC27843@lst.de>
From:   "jianchao.wang" <jianchao.w.wang@oracle.com>
Message-ID: <65152af5-9dc1-d6fb-6790-6055535f8048@oracle.com>
Date:   Tue, 8 May 2018 16:31:54 +0800
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Hi Christoph

On 05/07/2018 08:27 PM, Christoph Hellwig wrote:
> On Fri, May 04, 2018 at 04:02:18PM +0800, Jianchao Wang wrote:
>> BUG: KASAN: double-free or invalid-free in nvme_rdma_free_queue+0xf6/0x110 [nvme_rdma]
>> Workqueue: nvme-reset-wq nvme_rdma_reset_ctrl_work [nvme_rdma]
>> Call Trace:
>>  dump_stack+0x91/0xeb
>>  print_address_description+0x6b/0x290
>>  kasan_report_invalid_free+0x55/0x80
>>  __kasan_slab_free+0x176/0x190
>>  kfree+0xeb/0x310
>>  nvme_rdma_free_queue+0xf6/0x110 [nvme_rdma]
>>  nvme_rdma_configure_admin_queue+0x1a3/0x4d0 [nvme_rdma]
>>  nvme_rdma_reset_ctrl_work+0x4e/0xd0 [nvme_rdma]
>>  process_one_work+0x3ca/0xaa0
>>  worker_thread+0x4e2/0x6c0
>>  kthread+0x18d/0x1e0
>>  ret_from_fork+0x24/0x30
>>
>> The double free is on ctrl->async_event_sqe.
>> If nvme_rdma_start_queue in nvme_rdma_configure_admin_queue fails,
>> nvme_rdma_free_queue will be invoked. However, at the moment, the
>> ctrl->async_event_sqe has not been allocated and it has been freed
>> in
>> nvme_rdma_reset_ctrl_work
>>   -> nvme_rdma_shutdown_ctrl
>>     ->nvme_rdma_destroy_admin_queue
>>       -> nvme_rdma_free_queue
>>
>> Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com>
> 
> Can you handle this in the caller instead, maybe including a comment?
> 
Yes, that will be clearer.
Thanks for your suggestion.

Jianchao