• [PATCH v2] xhci: Cleanup current_cmd in xhci_cleanup_command_queue(

    From Mathias Nyman@21:1/5 to Jeffy Chen on Mon Oct 2 13:50:02 2017
    On 29.09.2017 14:07, Jeffy Chen wrote:
    KASAN reported use-after-free bug when xhci host controller died:
    [ 176.952537] BUG: KASAN: use-after-free in xhci_handle_command_timeout+0x68/0x224
    [ 176.960846] Write of size 4 at addr ffffffc0cbb01608 by task kworker/3:3/1680
    ...
    [ 177.180644] Freed by task 0:
    [ 177.183882] kasan_slab_free+0x90/0x15c
    [ 177.188194] kfree+0x114/0x28c
    [ 177.191630] xhci_cleanup_command_queue+0xc8/0xf8
    [ 177.196916] xhci_hc_died+0x84/0x358

    Problem here is that when the cmd_timer fired, it would try to access current_cmd while the command queue is already freed by xhci_hc_died().

    Cleanup current_cmd in xhci_cleanup_command_queue() to avoid that.

    Fixes: d9f11ba9f107 ("xhci: Rework how we handle unresponsive or hoptlug removed hosts")
    Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
    ---



    Thanks, adding patch to queue

    -Mathias

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