Re: [PATCH v2] xhci: solve a double free problem while doing s4

["gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>]

On Fri, Jun 11, 2021 at 11:08:30AM +0000, 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.
> 
> 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: Jiantao Zhang <water.zhangjiantao@huawei.com>
> Signed-off-by: Tao Xue <xuetao09@huawei.com>
> ---
>  drivers/usb/host/xhci-mem.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c index f66815f..e4b0c04 100644
> --- a/drivers/usb/host/xhci-mem.c
> +++ b/drivers/usb/host/xhci-mem.c
> @@ -1924,6 +1924,7 @@ void xhci_mem_cleanup(struct xhci_hcd *xhci)
>  	xhci->hw_ports = NULL;
>  	xhci->rh_bw = NULL;
>  	xhci->ext_caps = NULL;
> +	xhci->port_caps = NULL;
>  
>  	xhci->page_size = 0;
>  	xhci->page_shift = 0;
> --
> 2.7.4
> 


Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
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