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

gregkh
2021-06-11T13:13:16Z

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
a patch that has triggered this response. He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created. Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.

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Please read the section entitled "The canonical patch format" in the
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If you wish to discuss this problem further, or you have questions about
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thanks,

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