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| author | Jack Pham <jackp@codeaurora.org> | 2021-05-01 11:35:58 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-05-10 14:52:23 +0200 |
| commit | bb9c74a5bd1462499fe5ccb1e3c5ac40dcfa9139 (patch) | |
| tree | 886badd4c4b0a58ad6e33a7610f3f9cc2bbcf4be /drivers/usb | |
| parent | usb: dwc2: Fix gadget DMA unmap direction (diff) | |
| download | linux-bb9c74a5bd1462499fe5ccb1e3c5ac40dcfa9139.tar.xz linux-bb9c74a5bd1462499fe5ccb1e3c5ac40dcfa9139.zip | |
usb: dwc3: gadget: Free gadget structure only after freeing endpoints
As part of commit e81a7018d93a ("usb: dwc3: allocate gadget structure
dynamically") the dwc3_gadget_release() was added which will free
the dwc->gadget structure upon the device's removal when
usb_del_gadget_udc() is called in dwc3_gadget_exit().
However, simply freeing the gadget results a dangling pointer
situation: the endpoints created in dwc3_gadget_init_endpoints()
have their dep->endpoint.ep_list members chained off the list_head
anchored at dwc->gadget->ep_list. Thus when dwc->gadget is freed,
the first dwc3_ep in the list now has a dangling prev pointer and
likewise for the next pointer of the dwc3_ep at the tail of the list.
The dwc3_gadget_free_endpoints() that follows will result in a
use-after-free when it calls list_del().
This was caught by enabling KASAN and performing a driver unbind.
The recent commit 568262bf5492 ("usb: dwc3: core: Add shutdown
callback for dwc3") also exposes this as a panic during shutdown.
There are a few possibilities to fix this. One could be to perform
a list_del() of the gadget->ep_list itself which removes it from
the rest of the dwc3_ep chain.
Another approach is what this patch does, by splitting up the
usb_del_gadget_udc() call into its separate "del" and "put"
components. This allows dwc3_gadget_free_endpoints() to be
called before the gadget is finally freed with usb_put_gadget().
Fixes: e81a7018d93a ("usb: dwc3: allocate gadget structure dynamically")
Reviewed-by: Peter Chen <peter.chen@kernel.org>
Signed-off-by: Jack Pham <jackp@codeaurora.org>
Link: https://lore.kernel.org/r/20210501093558.7375-1-jackp@codeaurora.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb')
| -rw-r--r-- | drivers/usb/dwc3/gadget.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 6eab78f8a1a7..dd1342403bb2 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -4062,8 +4062,9 @@ err0: void dwc3_gadget_exit(struct dwc3 *dwc) { - usb_del_gadget_udc(dwc->gadget); + usb_del_gadget(dwc->gadget); dwc3_gadget_free_endpoints(dwc); + usb_put_gadget(dwc->gadget); dma_free_coherent(dwc->sysdev, DWC3_BOUNCE_SIZE, dwc->bounce, dwc->bounce_addr); kfree(dwc->setup_buf); |