Re: [PATCH] xhci: solve a double free problem while doing s4

[Mathias Nyman]

On 9.6.2021 17.22, Zhangjiantao (Kirin, nanjing) wrote:
> when system is doing s4, the process of xhci_resume may be as below:
> 1、xhci_mem_cleanup
> 2、xhci_init->xhci_mem_init->xhci_mem_cleanup(when memory is not enough).
> xhci_mem_cleanup will be executed twice when system is out of memory.
> xhci->port_caps is freed in xhci_mem_cleanup,but it isn't set to NULL.
> It will be freed twice when xhci_mem_cleanup is called the second time.
> 

Thanks, nice catch

> We got following bug when system resumes from s4:
> 
> kernel BUG at mm/slub.c:309!
> Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
> CPU: 0 PID: 5929 Tainted: G S   W   5.4.96-arm64-desktop #1
> pc : __slab_free+0x5c/0x424
> lr : kfree+0x30c/0x32c
> 
> Call trace:
>  __slab_free+0x5c/0x424
>  kfree+0x30c/0x32c
>  xhci_mem_cleanup+0x394/0x3cc
>  xhci_mem_init+0x9ac/0x1070
>  xhci_init+0x8c/0x1d0
>  xhci_resume+0x1cc/0x5fc
>  xhci_plat_resume+0x64/0x70
>  platform_pm_thaw+0x28/0x60
>  dpm_run_callback+0x54/0x24c
>  device_resume+0xd0/0x200
>  async_resume+0x24/0x60
>  async_run_entry_fn+0x44/0x110
>  process_one_work+0x1f0/0x490
>  worker_thread+0x5c/0x450
>  kthread+0x158/0x160
>  ret_from_fork+0x10/0x24
> 
> Signed-off-by: Tao Xue <xuetao09@xxxxxxxxxx>

Checkpatch complains:
ERROR: Missing Signed-off-by: line by nominal patch author 'Zhangjiantao (Kirin, nanjing) <water.zhangjiantao@xxxxxxxxxx>'

Is Zhangjiantao (Kirin, nanjing)  the correct author? If yes can I add 
"Signed-off-by: Zhangjiantao (Kirin, nanjing) <water.zhangjiantao@xxxxxxxxxx>?

I'll add the stable and correct fixes tags for this.

Thanks
Mathias