Re: [PATCH] xhci: Cancel cmd_timer before cleanup the command queue in xhci_hc_died()

[Greg Kroah-Hartman]

On Wed, Nov 01, 2017 at 06:28:01PM +0200, Mathias Nyman wrote:
> On 01.11.2017 18:03, Greg Kroah-Hartman wrote:
> > On Fri, Sep 29, 2017 at 05:12:47PM +0800, Jeffy Chen wrote:
> > > When the cmd_timer fired, it would try to access the command struct.
> > > So cancel it before cleanup the command queue in xhci_hc_died(), to
> > > avoid use-after-free reported by KASAN:
> > > [  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
> > > 
> > > Fixes: d9f11ba9f107 ("xhci: Rework how we handle unresponsive or hoptlug removed hosts")
> > > Signed-off-by: Jeffy Chen <jeffy.chen@xxxxxxxxxxxxxx>
> > > ---
> > 
> > Mathias, did you miss this one?  Want me to queue it up?
> > 
> 
> There is a v2 of that patch already upstreamed.
> 
> d1aad52 xhci: Cleanup current_cmd in xhci_cleanup_command_queue()
> 
> https://marc.info/?l=linux-usb&m=150668331802206&w=2
> 
> A bit confusing as patch subject changed as well in v2

Ah, thanks, missed that.

greg k-h