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

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

[Jeffy Chen]

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@rock-chips.com>
---

 drivers/usb/host/xhci-ring.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index a9443651ce0f..69ac3deffb7b 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -914,6 +914,7 @@ void xhci_hc_died(struct xhci_hcd *xhci)
 	xhci_err(xhci, "xHCI host controller not responding, assume dead\n");
 	xhci->xhc_state |= XHCI_STATE_DYING;
 
+	cancel_delayed_work_sync(&xhci->cmd_timer);
 	xhci_cleanup_command_queue(xhci);
 
 	/* return any pending urbs, remove may be waiting for them */
-- 
2.11.0

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

[Greg Kroah-Hartman]

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@rock-chips.com>
> ---

Mathias, did you miss this one?  Want me to queue it up?

thanks,

greg k-h

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

[Mathias Nyman]

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@rock-chips.com>
>> ---
>
> 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

-Mathias

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@rock-chips.com>
> > > ---
> > 
> > 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