Re: [PATCH] nvme-rdma: fix double free in nvme_rdma_free_queue

[jianchao.wang]

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@xxxxxxxxxx>
> 
> Can you handle this in the caller instead, maybe including a comment?
> 
Yes, that will be clearer.
Thanks for your suggestion.

Jianchao