Re: [PATCH] usb: xhci: Check kcalloc_node() when allocating interrupter array in xhci_mem_init()

[Michal Pecio <michal.pecio@gmail.com>]

On Thu, 18 Sep 2025 21:08:38 +0800, Guangshuo Li wrote:
> kcalloc_node() may fail. When the interrupter array allocation returns
> NULL, subsequent code uses xhci->interrupters (e.g. in xhci_add_interrupter()
> and in cleanup paths), leading to a potential NULL pointer dereference.
> 
> Check the allocation and bail out to the existing fail path to avoid
> the NULL dereference.
> 
> Fixes: c99b38c412343 ("xhci: add support to allocate several interrupters")
> Cc: stable@vger.kernel.org
> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
> ---
>  drivers/usb/host/xhci-mem.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
> index d698095fc88d..da257856e864 100644
> --- a/drivers/usb/host/xhci-mem.c
> +++ b/drivers/usb/host/xhci-mem.c
> @@ -2505,7 +2505,8 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
>  		       "Allocating primary event ring");
>  	xhci->interrupters = kcalloc_node(xhci->max_interrupters, sizeof(*xhci->interrupters),
>  					  flags, dev_to_node(dev));
> -
> +	if (!xhci->interrupters)
> +		goto fail;

This is a patch against some old kernel, this exact check has been
added in v6.16 by 83d98dea48eb6.

But it's missing Fixes and Cc:stable, so 6.6 and 6.12 were left broken.

>  	ir = xhci_alloc_interrupter(xhci, 0, flags);
>  	if (!ir)
>  		goto fail;
> -- 
> 2.43.0
>