Re: [PATCH V2] usb: tegra: Fix allocation for the FPCI context

[Greg Kroah-Hartman]

On Wed, Jul 15, 2020 at 12:38:42PM +0100, Jon Hunter wrote:
> Commit 5c4e8d3781bc ("usb: host: xhci-tegra: Add support for XUSB
> context save/restore") is using the IPFS 'num_offsets' value when
> allocating memory for FPCI context instead of the FPCI 'num_offsets'.
> 
> After commit cad064f1bd52 ("devres: handle zero size in devm_kmalloc()")
> was added system suspend started failing on Tegra186. The kernel log
> showed that the Tegra XHCI driver was crashing on entry to suspend when
> attempting the save the USB context. On Tegra186, the IPFS context has a
> zero length but the FPCI content has a non-zero length, and because of
> the bug in the Tegra XHCI driver we are incorrectly allocating a zero
> length array for the FPCI context. The crash seen on entering suspend
> when we attempt to save the FPCI context and following commit
> cad064f1bd52 ("devres: handle zero size in devm_kmalloc()") this now
> causes a NULL pointer deference when we access the memory. Fix this by
> correcting the amount of memory we are allocating for FPCI contexts.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> 
> Fixes: 5c4e8d3781bc ("usb: host: xhci-tegra: Add support for XUSB context save/restore")
> 
> Signed-off-by: Jon Hunter <jonathanh@xxxxxxxxxx>
> Acked-by: Thierry Reding <treding@xxxxxxxxxx>
> ---
> 
> Changes since V1:
> - Corrected commit message
> - Added Thierry's ACK
> 
>  drivers/usb/host/xhci-tegra.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

No cc: to linux-usb@vger?  :(

I'll go queue this up, but I would have caught it sooner if you had done
so...

thanks,

greg k-h