The vub300 driver maintains an explicit reference count for the
controller and its driver data and the last reference can in theory be
dropped after the driver has been unbound.
This specifically means that the controller allocation must not be
device managed as that can lead to use-after-free.
Note that the lifetime is currently also incorrectly tied the parent USB
device rather than interface, which can lead to memory leaks if the
driver is unbound without its device being physically disconnected (e.g.
on probe deferral).
Fix both issues by reverting to non-managed allocation of the controller.
Fixes: dcfdd698dc52 ("mmc: vub300: Use devm_mmc_alloc_host() helper")
Cc: stable@vger.kernel.org # 6.17
Cc: Binbin Zhou <zhoubinbin@loongson.cn>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
drivers/mmc/host/vub300.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/drivers/mmc/host/vub300.c b/drivers/mmc/host/vub300.c
index f173c7cf4e1a..3c9df27f9fa7 100644
--- a/drivers/mmc/host/vub300.c
+++ b/drivers/mmc/host/vub300.c
@@ -369,11 +369,14 @@ struct vub300_mmc_host {
static void vub300_delete(struct kref *kref)
{ /* kref callback - softirq */
struct vub300_mmc_host *vub300 = kref_to_vub300_mmc_host(kref);
+ struct mmc_host *mmc = vub300->mmc;
+
usb_free_urb(vub300->command_out_urb);
vub300->command_out_urb = NULL;
usb_free_urb(vub300->command_res_urb);
vub300->command_res_urb = NULL;
usb_put_dev(vub300->udev);
+ mmc_free_host(mmc);
/*
* and hence also frees vub300
* which is contained at the end of struct mmc
@@ -2112,7 +2115,7 @@ static int vub300_probe(struct usb_interface *interface,
goto error1;
}
/* this also allocates memory for our VUB300 mmc host device */
- mmc = devm_mmc_alloc_host(&udev->dev, sizeof(*vub300));
+ mmc = mmc_alloc_host(sizeof(*vub300), &udev->dev);
if (!mmc) {
retval = -ENOMEM;
dev_err(&udev->dev, "not enough memory for the mmc_host\n");
@@ -2269,7 +2272,7 @@ static int vub300_probe(struct usb_interface *interface,
dev_err(&vub300->udev->dev,
"Could not find two sets of bulk-in/out endpoint pairs\n");
retval = -EINVAL;
- goto error4;
+ goto err_free_host;
}
retval =
usb_control_msg(vub300->udev, usb_rcvctrlpipe(vub300->udev, 0),
@@ -2278,14 +2281,14 @@ static int vub300_probe(struct usb_interface *interface,
0x0000, 0x0000, &vub300->hc_info,
sizeof(vub300->hc_info), 1000);
if (retval < 0)
- goto error4;
+ goto err_free_host;
retval =
usb_control_msg(vub300->udev, usb_sndctrlpipe(vub300->udev, 0),
SET_ROM_WAIT_STATES,
USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
firmware_rom_wait_states, 0x0000, NULL, 0, 1000);
if (retval < 0)
- goto error4;
+ goto err_free_host;
dev_info(&vub300->udev->dev,
"operating_mode = %s %s %d MHz %s %d byte USB packets\n",
(mmc->caps & MMC_CAP_SDIO_IRQ) ? "IRQs" : "POLL",
@@ -2300,7 +2303,7 @@ static int vub300_probe(struct usb_interface *interface,
0x0000, 0x0000, &vub300->system_port_status,
sizeof(vub300->system_port_status), 1000);
if (retval < 0) {
- goto error4;
+ goto err_free_host;
} else if (sizeof(vub300->system_port_status) == retval) {
vub300->card_present =
(0x0001 & vub300->system_port_status.port_flags) ? 1 : 0;
@@ -2308,7 +2311,7 @@ static int vub300_probe(struct usb_interface *interface,
(0x0010 & vub300->system_port_status.port_flags) ? 1 : 0;
} else {
retval = -EINVAL;
- goto error4;
+ goto err_free_host;
}
usb_set_intfdata(interface, vub300);
INIT_DELAYED_WORK(&vub300->pollwork, vub300_pollwork_thread);
@@ -2338,6 +2341,8 @@ static int vub300_probe(struct usb_interface *interface,
return 0;
error6:
timer_delete_sync(&vub300->inactivity_timer);
+err_free_host:
+ mmc_free_host(mmc);
/*
* and hence also frees vub300
* which is contained at the end of struct mmc
--
2.52.0On Fri, 27 Mar 2026 at 11:52, Johan Hovold <johan@kernel.org> wrote:
>
> The vub300 driver maintains an explicit reference count for the
> controller and its driver data and the last reference can in theory be
> dropped after the driver has been unbound.
>
> This specifically means that the controller allocation must not be
> device managed as that can lead to use-after-free.
>
> Note that the lifetime is currently also incorrectly tied the parent USB
> device rather than interface, which can lead to memory leaks if the
> driver is unbound without its device being physically disconnected (e.g.
> on probe deferral).
>
> Fix both issues by reverting to non-managed allocation of the controller.
Huh, sounds like a real mess, but thanks for the detailed description.
I will defer applying until we finalize the discussion on patch1, but
otherwise this looks good to me.
Kind regards
Uffe
>
> Fixes: dcfdd698dc52 ("mmc: vub300: Use devm_mmc_alloc_host() helper")
> Cc: stable@vger.kernel.org # 6.17
> Cc: Binbin Zhou <zhoubinbin@loongson.cn>
> Signed-off-by: Johan Hovold <johan@kernel.org>
> ---
> drivers/mmc/host/vub300.c | 17 +++++++++++------
> 1 file changed, 11 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/mmc/host/vub300.c b/drivers/mmc/host/vub300.c
> index f173c7cf4e1a..3c9df27f9fa7 100644
> --- a/drivers/mmc/host/vub300.c
> +++ b/drivers/mmc/host/vub300.c
> @@ -369,11 +369,14 @@ struct vub300_mmc_host {
> static void vub300_delete(struct kref *kref)
> { /* kref callback - softirq */
> struct vub300_mmc_host *vub300 = kref_to_vub300_mmc_host(kref);
> + struct mmc_host *mmc = vub300->mmc;
> +
> usb_free_urb(vub300->command_out_urb);
> vub300->command_out_urb = NULL;
> usb_free_urb(vub300->command_res_urb);
> vub300->command_res_urb = NULL;
> usb_put_dev(vub300->udev);
> + mmc_free_host(mmc);
> /*
> * and hence also frees vub300
> * which is contained at the end of struct mmc
> @@ -2112,7 +2115,7 @@ static int vub300_probe(struct usb_interface *interface,
> goto error1;
> }
> /* this also allocates memory for our VUB300 mmc host device */
> - mmc = devm_mmc_alloc_host(&udev->dev, sizeof(*vub300));
> + mmc = mmc_alloc_host(sizeof(*vub300), &udev->dev);
> if (!mmc) {
> retval = -ENOMEM;
> dev_err(&udev->dev, "not enough memory for the mmc_host\n");
> @@ -2269,7 +2272,7 @@ static int vub300_probe(struct usb_interface *interface,
> dev_err(&vub300->udev->dev,
> "Could not find two sets of bulk-in/out endpoint pairs\n");
> retval = -EINVAL;
> - goto error4;
> + goto err_free_host;
> }
> retval =
> usb_control_msg(vub300->udev, usb_rcvctrlpipe(vub300->udev, 0),
> @@ -2278,14 +2281,14 @@ static int vub300_probe(struct usb_interface *interface,
> 0x0000, 0x0000, &vub300->hc_info,
> sizeof(vub300->hc_info), 1000);
> if (retval < 0)
> - goto error4;
> + goto err_free_host;
> retval =
> usb_control_msg(vub300->udev, usb_sndctrlpipe(vub300->udev, 0),
> SET_ROM_WAIT_STATES,
> USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
> firmware_rom_wait_states, 0x0000, NULL, 0, 1000);
> if (retval < 0)
> - goto error4;
> + goto err_free_host;
> dev_info(&vub300->udev->dev,
> "operating_mode = %s %s %d MHz %s %d byte USB packets\n",
> (mmc->caps & MMC_CAP_SDIO_IRQ) ? "IRQs" : "POLL",
> @@ -2300,7 +2303,7 @@ static int vub300_probe(struct usb_interface *interface,
> 0x0000, 0x0000, &vub300->system_port_status,
> sizeof(vub300->system_port_status), 1000);
> if (retval < 0) {
> - goto error4;
> + goto err_free_host;
> } else if (sizeof(vub300->system_port_status) == retval) {
> vub300->card_present =
> (0x0001 & vub300->system_port_status.port_flags) ? 1 : 0;
> @@ -2308,7 +2311,7 @@ static int vub300_probe(struct usb_interface *interface,
> (0x0010 & vub300->system_port_status.port_flags) ? 1 : 0;
> } else {
> retval = -EINVAL;
> - goto error4;
> + goto err_free_host;
> }
> usb_set_intfdata(interface, vub300);
> INIT_DELAYED_WORK(&vub300->pollwork, vub300_pollwork_thread);
> @@ -2338,6 +2341,8 @@ static int vub300_probe(struct usb_interface *interface,
> return 0;
> error6:
> timer_delete_sync(&vub300->inactivity_timer);
> +err_free_host:
> + mmc_free_host(mmc);
> /*
> * and hence also frees vub300
> * which is contained at the end of struct mmc
> --
> 2.52.0
>
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