sound/usb/caiaq/device.c | 19 +++++++++++-------- sound/usb/caiaq/device.h | 2 +- 2 files changed, 12 insertions(+), 9 deletions(-)
The epq_in_urb object belonging to the caiaq device is coupled within
the struct snd_usb_caiaqdev. After usb_submit_urb(epq_in_urb, GFP_KERNEL)
executes successfully, epq_in_urb is successfully added to the urbp_list
queue of the dummy HCD driver (userspace specifies dummy_hcd as the HCD
layer driver for the caiaq USB device).
When init_card() calls snd_usb_caiaq_send_command() which subsequently
fails due to a timeout, and proceeds to call snd_card_free() to release
the card, the embedded ep1_in_urb object is also freed. When the dummy
HCD driver detects that the URB has been unlinked, it returns the URB
(by usb_hcd_giveback_urb()), which triggers [1].
Decouple the ep1_in_urb object from the struct snd_usb_caiaqdev and switch
to using a pointer instead. Separately allocate and manage the memory for
ep1_in_urb to prevent the release of the snd_card memory object from
interfering with it.
[1]
BUG: KASAN: slab-use-after-free in usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96
Write of size 4 at addr ffff88803cee1050 by task ktimers/1/29
Call Trace:
usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96
dummy_timer+0xaac/0x4d50 drivers/usb/gadget/udc/dummy_hcd.c:2019
__run_hrtimer kernel/time/hrtimer.c:2067 [inline]
__hrtimer_run_queues+0x3eb/0xaf0 kernel/time/hrtimer.c:2124
hrtimer_run_softirq+0x1e1/0x2e0 kernel/time/hrtimer.c:2141
Allocated by task 36:
snd_card_new+0x7b/0x110 sound/core/init.c:184
create_card sound/usb/caiaq/device.c:429 [inline]
snd_probe+0x236/0x1af0 sound/usb/caiaq/device.c:544
Freed by task 36:
snd_card_free_when_closed sound/core/init.c:630 [inline]
snd_card_free+0x138/0x1d0 sound/core/init.c:662
snd_probe+0x162b/0x1af0 sound/usb/caiaq/device.c:553
Reported-by: syzbot+832ce9fa3face1b7d44d@syzkaller.appspotmail.com
Fixes: 523f1dce3743 ("[ALSA] Add Native Instrument usb audio device support")
Closes: https://syzkaller.appspot.com/bug?extid=832ce9fa3face1b7d44d
Tested-by: syzbot+832ce9fa3face1b7d44d@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@sina.com>
---
sound/usb/caiaq/device.c | 19 +++++++++++--------
sound/usb/caiaq/device.h | 2 +-
2 files changed, 12 insertions(+), 9 deletions(-)
diff --git a/sound/usb/caiaq/device.c b/sound/usb/caiaq/device.c
index a16e59248480..138b58914f1c 100644
--- a/sound/usb/caiaq/device.c
+++ b/sound/usb/caiaq/device.c
@@ -192,8 +192,8 @@ static void usb_ep1_command_reply_dispatch (struct urb* urb)
break;
}
- cdev->ep1_in_urb.actual_length = 0;
- ret = usb_submit_urb(&cdev->ep1_in_urb, GFP_ATOMIC);
+ cdev->ep1_in_urb->actual_length = 0;
+ ret = usb_submit_urb(cdev->ep1_in_urb, GFP_ATOMIC);
if (ret < 0)
dev_err(dev, "unable to submit urb. OOM!?\n");
}
@@ -408,6 +408,8 @@ static void card_free(struct snd_card *card)
#endif
snd_usb_caiaq_audio_free(cdev);
usb_put_dev(cdev->chip.dev);
+ usb_free_urb(cdev->ep1_in_urb);
+ cdev->ep1_in_urb = NULL;
}
static int create_card(struct usb_device *usb_dev,
@@ -457,10 +459,11 @@ static int init_card(struct snd_usb_caiaqdev *cdev)
return -EIO;
}
- usb_init_urb(&cdev->ep1_in_urb);
+ cdev->ep1_in_urb = usb_alloc_urb(0, GFP_KERNEL);
+ usb_init_urb(cdev->ep1_in_urb);
usb_init_urb(&cdev->midi_out_urb);
- usb_fill_bulk_urb(&cdev->ep1_in_urb, usb_dev,
+ usb_fill_bulk_urb(cdev->ep1_in_urb, usb_dev,
usb_rcvbulkpipe(usb_dev, 0x1),
cdev->ep1_in_buf, EP1_BUFSIZE,
usb_ep1_command_reply_dispatch, cdev);
@@ -471,7 +474,7 @@ static int init_card(struct snd_usb_caiaqdev *cdev)
snd_usb_caiaq_midi_output_done, cdev);
/* sanity checks of EPs before actually submitting */
- if (usb_urb_ep_type_check(&cdev->ep1_in_urb) ||
+ if (usb_urb_ep_type_check(cdev->ep1_in_urb) ||
usb_urb_ep_type_check(&cdev->midi_out_urb)) {
dev_err(dev, "invalid EPs\n");
return -EINVAL;
@@ -480,7 +483,7 @@ static int init_card(struct snd_usb_caiaqdev *cdev)
init_waitqueue_head(&cdev->ep1_wait_queue);
init_waitqueue_head(&cdev->prepare_wait_queue);
- if (usb_submit_urb(&cdev->ep1_in_urb, GFP_KERNEL) != 0)
+ if (usb_submit_urb(cdev->ep1_in_urb, GFP_KERNEL) != 0)
return -EIO;
err = snd_usb_caiaq_send_command(cdev, EP1_CMD_GET_DEVICE_INFO, NULL, 0);
@@ -530,7 +533,7 @@ static int init_card(struct snd_usb_caiaqdev *cdev)
return 0;
err_kill_urb:
- usb_kill_urb(&cdev->ep1_in_urb);
+ usb_kill_urb(cdev->ep1_in_urb);
return err;
}
@@ -576,7 +579,7 @@ static void snd_disconnect(struct usb_interface *intf)
#endif
snd_usb_caiaq_audio_disconnect(cdev);
- usb_kill_urb(&cdev->ep1_in_urb);
+ usb_kill_urb(cdev->ep1_in_urb);
usb_kill_urb(&cdev->midi_out_urb);
snd_card_free_when_closed(card);
diff --git a/sound/usb/caiaq/device.h b/sound/usb/caiaq/device.h
index 743eb0387b5f..a5f7dada25d8 100644
--- a/sound/usb/caiaq/device.h
+++ b/sound/usb/caiaq/device.h
@@ -60,7 +60,7 @@ struct snd_usb_caiaq_cb_info;
struct snd_usb_caiaqdev {
struct snd_usb_audio chip;
- struct urb ep1_in_urb;
+ struct urb *ep1_in_urb;
struct urb midi_out_urb;
struct urb **data_urbs_in;
struct urb **data_urbs_out;
--
2.43.0On Thu, 03 Sep 2026 10:47:47 +0200,
Edward Adam Davis wrote:
>
> The epq_in_urb object belonging to the caiaq device is coupled within
> the struct snd_usb_caiaqdev. After usb_submit_urb(epq_in_urb, GFP_KERNEL)
> executes successfully, epq_in_urb is successfully added to the urbp_list
> queue of the dummy HCD driver (userspace specifies dummy_hcd as the HCD
> layer driver for the caiaq USB device).
>
> When init_card() calls snd_usb_caiaq_send_command() which subsequently
> fails due to a timeout, and proceeds to call snd_card_free() to release
> the card, the embedded ep1_in_urb object is also freed. When the dummy
> HCD driver detects that the URB has been unlinked, it returns the URB
> (by usb_hcd_giveback_urb()), which triggers [1].
>
> Decouple the ep1_in_urb object from the struct snd_usb_caiaqdev and switch
> to using a pointer instead. Separately allocate and manage the memory for
> ep1_in_urb to prevent the release of the snd_card memory object from
> interfering with it.
>
> [1]
> BUG: KASAN: slab-use-after-free in usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96
> Write of size 4 at addr ffff88803cee1050 by task ktimers/1/29
> Call Trace:
> usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96
> dummy_timer+0xaac/0x4d50 drivers/usb/gadget/udc/dummy_hcd.c:2019
> __run_hrtimer kernel/time/hrtimer.c:2067 [inline]
> __hrtimer_run_queues+0x3eb/0xaf0 kernel/time/hrtimer.c:2124
> hrtimer_run_softirq+0x1e1/0x2e0 kernel/time/hrtimer.c:2141
>
> Allocated by task 36:
> snd_card_new+0x7b/0x110 sound/core/init.c:184
> create_card sound/usb/caiaq/device.c:429 [inline]
> snd_probe+0x236/0x1af0 sound/usb/caiaq/device.c:544
>
> Freed by task 36:
> snd_card_free_when_closed sound/core/init.c:630 [inline]
> snd_card_free+0x138/0x1d0 sound/core/init.c:662
> snd_probe+0x162b/0x1af0 sound/usb/caiaq/device.c:553
>
> Reported-by: syzbot+832ce9fa3face1b7d44d@syzkaller.appspotmail.com
> Fixes: 523f1dce3743 ("[ALSA] Add Native Instrument usb audio device support")
> Closes: https://syzkaller.appspot.com/bug?extid=832ce9fa3face1b7d44d
> Tested-by: syzbot+832ce9fa3face1b7d44d@syzkaller.appspotmail.com
> Signed-off-by: Edward Adam Davis <eadavis@sina.com>
> ---
> sound/usb/caiaq/device.c | 19 +++++++++++--------
> sound/usb/caiaq/device.h | 2 +-
> 2 files changed, 12 insertions(+), 9 deletions(-)
>
> diff --git a/sound/usb/caiaq/device.c b/sound/usb/caiaq/device.c
> index a16e59248480..138b58914f1c 100644
> --- a/sound/usb/caiaq/device.c
> +++ b/sound/usb/caiaq/device.c
> @@ -192,8 +192,8 @@ static void usb_ep1_command_reply_dispatch (struct urb* urb)
> break;
> }
>
> - cdev->ep1_in_urb.actual_length = 0;
> - ret = usb_submit_urb(&cdev->ep1_in_urb, GFP_ATOMIC);
> + cdev->ep1_in_urb->actual_length = 0;
> + ret = usb_submit_urb(cdev->ep1_in_urb, GFP_ATOMIC);
> if (ret < 0)
> dev_err(dev, "unable to submit urb. OOM!?\n");
> }
> @@ -408,6 +408,8 @@ static void card_free(struct snd_card *card)
> #endif
> snd_usb_caiaq_audio_free(cdev);
> usb_put_dev(cdev->chip.dev);
> + usb_free_urb(cdev->ep1_in_urb);
> + cdev->ep1_in_urb = NULL;
> }
>
> static int create_card(struct usb_device *usb_dev,
> @@ -457,10 +459,11 @@ static int init_card(struct snd_usb_caiaqdev *cdev)
> return -EIO;
> }
>
> - usb_init_urb(&cdev->ep1_in_urb);
> + cdev->ep1_in_urb = usb_alloc_urb(0, GFP_KERNEL);
> + usb_init_urb(cdev->ep1_in_urb);
The error check is missing here, as sashiko review pointed out.
Could you fix and resubmit?
(The other issues reported there -- the potential-double-free and the
midi_out_urb handling can be skipped here; I'll fix those
individually.)
thanks,
Takashi
From: Edward Aadm Davis <eadavis@sina.com>
On Thu, 03 Sep 2026 11:32:22 +0200, Takashi Iwai wrote:
> > The epq_in_urb object belonging to the caiaq device is coupled within
> > the struct snd_usb_caiaqdev. After usb_submit_urb(epq_in_urb, GFP_KERNEL)
> > executes successfully, epq_in_urb is successfully added to the urbp_list
> > queue of the dummy HCD driver (userspace specifies dummy_hcd as the HCD
> > layer driver for the caiaq USB device).
> >
> > When init_card() calls snd_usb_caiaq_send_command() which subsequently
> > fails due to a timeout, and proceeds to call snd_card_free() to release
> > the card, the embedded ep1_in_urb object is also freed. When the dummy
> > HCD driver detects that the URB has been unlinked, it returns the URB
> > (by usb_hcd_giveback_urb()), which triggers [1].
> >
> > Decouple the ep1_in_urb object from the struct snd_usb_caiaqdev and switch
> > to using a pointer instead. Separately allocate and manage the memory for
> > ep1_in_urb to prevent the release of the snd_card memory object from
> > interfering with it.
> >
> > [1]
> > BUG: KASAN: slab-use-after-free in usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96
> > Write of size 4 at addr ffff88803cee1050 by task ktimers/1/29
> > Call Trace:
> > usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96
> > dummy_timer+0xaac/0x4d50 drivers/usb/gadget/udc/dummy_hcd.c:2019
> > __run_hrtimer kernel/time/hrtimer.c:2067 [inline]
> > __hrtimer_run_queues+0x3eb/0xaf0 kernel/time/hrtimer.c:2124
> > hrtimer_run_softirq+0x1e1/0x2e0 kernel/time/hrtimer.c:2141
> >
> > Allocated by task 36:
> > snd_card_new+0x7b/0x110 sound/core/init.c:184
> > create_card sound/usb/caiaq/device.c:429 [inline]
> > snd_probe+0x236/0x1af0 sound/usb/caiaq/device.c:544
> >
> > Freed by task 36:
> > snd_card_free_when_closed sound/core/init.c:630 [inline]
> > snd_card_free+0x138/0x1d0 sound/core/init.c:662
> > snd_probe+0x162b/0x1af0 sound/usb/caiaq/device.c:553
> >
> > Reported-by: syzbot+832ce9fa3face1b7d44d@syzkaller.appspotmail.com
> > Fixes: 523f1dce3743 ("[ALSA] Add Native Instrument usb audio device support")
> > Closes: https://syzkaller.appspot.com/bug?extid=832ce9fa3face1b7d44d
> > Tested-by: syzbot+832ce9fa3face1b7d44d@syzkaller.appspotmail.com
> > Signed-off-by: Edward Adam Davis <eadavis@sina.com>
> > ---
> > sound/usb/caiaq/device.c | 19 +++++++++++--------
> > sound/usb/caiaq/device.h | 2 +-
> > 2 files changed, 12 insertions(+), 9 deletions(-)
> >
> > diff --git a/sound/usb/caiaq/device.c b/sound/usb/caiaq/device.c
> > index a16e59248480..138b58914f1c 100644
> > --- a/sound/usb/caiaq/device.c
> > +++ b/sound/usb/caiaq/device.c
> > @@ -192,8 +192,8 @@ static void usb_ep1_command_reply_dispatch (struct urb* urb)
> > break;
> > }
> >
> > - cdev->ep1_in_urb.actual_length = 0;
> > - ret = usb_submit_urb(&cdev->ep1_in_urb, GFP_ATOMIC);
> > + cdev->ep1_in_urb->actual_length = 0;
> > + ret = usb_submit_urb(cdev->ep1_in_urb, GFP_ATOMIC);
> > if (ret < 0)
> > dev_err(dev, "unable to submit urb. OOM!?\n");
> > }
> > @@ -408,6 +408,8 @@ static void card_free(struct snd_card *card)
> > #endif
> > snd_usb_caiaq_audio_free(cdev);
> > usb_put_dev(cdev->chip.dev);
> > + usb_free_urb(cdev->ep1_in_urb);
> > + cdev->ep1_in_urb = NULL;
> > }
> >
> > static int create_card(struct usb_device *usb_dev,
> > @@ -457,10 +459,11 @@ static int init_card(struct snd_usb_caiaqdev *cdev)
> > return -EIO;
> > }
> >
> > - usb_init_urb(&cdev->ep1_in_urb);
> > + cdev->ep1_in_urb = usb_alloc_urb(0, GFP_KERNEL);
> > + usb_init_urb(cdev->ep1_in_urb);
>
> The error check is missing here, as sashiko review pointed out.
> Could you fix and resubmit?
OK. I will fix and resubmit.
>
> (The other issues reported there -- the potential-double-free and the
> midi_out_urb handling can be skipped here; I'll fix those
> individually.)
I can handle `midi_out_urb` as well.
BR,
Edward
On Thu, 03 Sep 2026 11:41:05 +0200,
Edward Adam Davis wrote:
>
> From: Edward Aadm Davis <eadavis@sina.com>
>
> On Thu, 03 Sep 2026 11:32:22 +0200, Takashi Iwai wrote:
> > > The epq_in_urb object belonging to the caiaq device is coupled within
> > > the struct snd_usb_caiaqdev. After usb_submit_urb(epq_in_urb, GFP_KERNEL)
> > > executes successfully, epq_in_urb is successfully added to the urbp_list
> > > queue of the dummy HCD driver (userspace specifies dummy_hcd as the HCD
> > > layer driver for the caiaq USB device).
> > >
> > > When init_card() calls snd_usb_caiaq_send_command() which subsequently
> > > fails due to a timeout, and proceeds to call snd_card_free() to release
> > > the card, the embedded ep1_in_urb object is also freed. When the dummy
> > > HCD driver detects that the URB has been unlinked, it returns the URB
> > > (by usb_hcd_giveback_urb()), which triggers [1].
> > >
> > > Decouple the ep1_in_urb object from the struct snd_usb_caiaqdev and switch
> > > to using a pointer instead. Separately allocate and manage the memory for
> > > ep1_in_urb to prevent the release of the snd_card memory object from
> > > interfering with it.
> > >
> > > [1]
> > > BUG: KASAN: slab-use-after-free in usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96
> > > Write of size 4 at addr ffff88803cee1050 by task ktimers/1/29
> > > Call Trace:
> > > usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96
> > > dummy_timer+0xaac/0x4d50 drivers/usb/gadget/udc/dummy_hcd.c:2019
> > > __run_hrtimer kernel/time/hrtimer.c:2067 [inline]
> > > __hrtimer_run_queues+0x3eb/0xaf0 kernel/time/hrtimer.c:2124
> > > hrtimer_run_softirq+0x1e1/0x2e0 kernel/time/hrtimer.c:2141
> > >
> > > Allocated by task 36:
> > > snd_card_new+0x7b/0x110 sound/core/init.c:184
> > > create_card sound/usb/caiaq/device.c:429 [inline]
> > > snd_probe+0x236/0x1af0 sound/usb/caiaq/device.c:544
> > >
> > > Freed by task 36:
> > > snd_card_free_when_closed sound/core/init.c:630 [inline]
> > > snd_card_free+0x138/0x1d0 sound/core/init.c:662
> > > snd_probe+0x162b/0x1af0 sound/usb/caiaq/device.c:553
> > >
> > > Reported-by: syzbot+832ce9fa3face1b7d44d@syzkaller.appspotmail.com
> > > Fixes: 523f1dce3743 ("[ALSA] Add Native Instrument usb audio device support")
> > > Closes: https://syzkaller.appspot.com/bug?extid=832ce9fa3face1b7d44d
> > > Tested-by: syzbot+832ce9fa3face1b7d44d@syzkaller.appspotmail.com
> > > Signed-off-by: Edward Adam Davis <eadavis@sina.com>
> > > ---
> > > sound/usb/caiaq/device.c | 19 +++++++++++--------
> > > sound/usb/caiaq/device.h | 2 +-
> > > 2 files changed, 12 insertions(+), 9 deletions(-)
> > >
> > > diff --git a/sound/usb/caiaq/device.c b/sound/usb/caiaq/device.c
> > > index a16e59248480..138b58914f1c 100644
> > > --- a/sound/usb/caiaq/device.c
> > > +++ b/sound/usb/caiaq/device.c
> > > @@ -192,8 +192,8 @@ static void usb_ep1_command_reply_dispatch (struct urb* urb)
> > > break;
> > > }
> > >
> > > - cdev->ep1_in_urb.actual_length = 0;
> > > - ret = usb_submit_urb(&cdev->ep1_in_urb, GFP_ATOMIC);
> > > + cdev->ep1_in_urb->actual_length = 0;
> > > + ret = usb_submit_urb(cdev->ep1_in_urb, GFP_ATOMIC);
> > > if (ret < 0)
> > > dev_err(dev, "unable to submit urb. OOM!?\n");
> > > }
> > > @@ -408,6 +408,8 @@ static void card_free(struct snd_card *card)
> > > #endif
> > > snd_usb_caiaq_audio_free(cdev);
> > > usb_put_dev(cdev->chip.dev);
> > > + usb_free_urb(cdev->ep1_in_urb);
> > > + cdev->ep1_in_urb = NULL;
> > > }
> > >
> > > static int create_card(struct usb_device *usb_dev,
> > > @@ -457,10 +459,11 @@ static int init_card(struct snd_usb_caiaqdev *cdev)
> > > return -EIO;
> > > }
> > >
> > > - usb_init_urb(&cdev->ep1_in_urb);
> > > + cdev->ep1_in_urb = usb_alloc_urb(0, GFP_KERNEL);
> > > + usb_init_urb(cdev->ep1_in_urb);
> >
> > The error check is missing here, as sashiko review pointed out.
> > Could you fix and resubmit?
> OK. I will fix and resubmit.
> >
> > (The other issues reported there -- the potential-double-free and the
> > midi_out_urb handling can be skipped here; I'll fix those
> > individually.)
> I can handle `midi_out_urb` as well.
OK, then let's shoot both URBs in a shot.
thanks,
Takashi
The epq_in_urb object belonging to the caiaq device is coupled within
the struct snd_usb_caiaqdev. After usb_submit_urb(epq_in_urb, GFP_KERNEL)
executes successfully, epq_in_urb is successfully added to the urbp_list
queue of the dummy HCD driver (userspace specifies dummy_hcd as the HCD
layer driver for the caiaq USB device).
When init_card() calls snd_usb_caiaq_send_command() which subsequently
fails due to a timeout, and proceeds to call snd_card_free() to release
the card, the embedded ep1_in_urb object is also freed. When the dummy
HCD driver detects that the URB has been unlinked, it returns the URB
(by usb_hcd_giveback_urb()), which triggers [1].
Decouple the ep1_in_urb object from the struct snd_usb_caiaqdev and switch
to using a pointer instead. Separately allocate and manage the memory for
ep1_in_urb to prevent the release of the snd_card memory object from
interfering with it.
midi_out_urb has the same issue as ep1_in_urb and is handled in the same
way.
[1]
BUG: KASAN: slab-use-after-free in usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96
Write of size 4 at addr ffff88803cee1050 by task ktimers/1/29
Call Trace:
usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96
dummy_timer+0xaac/0x4d50 drivers/usb/gadget/udc/dummy_hcd.c:2019
__run_hrtimer kernel/time/hrtimer.c:2067 [inline]
__hrtimer_run_queues+0x3eb/0xaf0 kernel/time/hrtimer.c:2124
hrtimer_run_softirq+0x1e1/0x2e0 kernel/time/hrtimer.c:2141
Allocated by task 36:
snd_card_new+0x7b/0x110 sound/core/init.c:184
create_card sound/usb/caiaq/device.c:429 [inline]
snd_probe+0x236/0x1af0 sound/usb/caiaq/device.c:544
Freed by task 36:
snd_card_free_when_closed sound/core/init.c:630 [inline]
snd_card_free+0x138/0x1d0 sound/core/init.c:662
snd_probe+0x162b/0x1af0 sound/usb/caiaq/device.c:553
Fixes: 523f1dce3743 ("[ALSA] Add Native Instrument usb audio device support")
Reported-by: syzbot+832ce9fa3face1b7d44d@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=832ce9fa3face1b7d44d
Tested-by: syzbot+832ce9fa3face1b7d44d@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@sina.com>
---
v1 -> v2: same dealwith midi_out_urb and add missing check
v2 -> v3: set ep1_in_urb to NULL after midi_out_urb allow failed
remove err message when alloc failed
sound/usb/caiaq/device.c | 38 ++++++++++++++++++++++++++------------
sound/usb/caiaq/device.h | 4 ++--
sound/usb/caiaq/midi.c | 6 +++---
3 files changed, 31 insertions(+), 17 deletions(-)
diff --git a/sound/usb/caiaq/device.c b/sound/usb/caiaq/device.c
index a16e59248480..ff761978a1cf 100644
--- a/sound/usb/caiaq/device.c
+++ b/sound/usb/caiaq/device.c
@@ -192,8 +192,8 @@ static void usb_ep1_command_reply_dispatch (struct urb* urb)
break;
}
- cdev->ep1_in_urb.actual_length = 0;
- ret = usb_submit_urb(&cdev->ep1_in_urb, GFP_ATOMIC);
+ cdev->ep1_in_urb->actual_length = 0;
+ ret = usb_submit_urb(cdev->ep1_in_urb, GFP_ATOMIC);
if (ret < 0)
dev_err(dev, "unable to submit urb. OOM!?\n");
}
@@ -408,6 +408,10 @@ static void card_free(struct snd_card *card)
#endif
snd_usb_caiaq_audio_free(cdev);
usb_put_dev(cdev->chip.dev);
+ usb_free_urb(cdev->ep1_in_urb);
+ cdev->ep1_in_urb = NULL;
+ usb_free_urb(cdev->midi_out_urb);
+ cdev->midi_out_urb = NULL;
}
static int create_card(struct usb_device *usb_dev,
@@ -457,22 +461,32 @@ static int init_card(struct snd_usb_caiaqdev *cdev)
return -EIO;
}
- usb_init_urb(&cdev->ep1_in_urb);
- usb_init_urb(&cdev->midi_out_urb);
+ cdev->ep1_in_urb = usb_alloc_urb(0, GFP_KERNEL);
+ if (!cdev->ep1_in_urb)
+ return -ENOMEM;
- usb_fill_bulk_urb(&cdev->ep1_in_urb, usb_dev,
+ cdev->midi_out_urb = usb_alloc_urb(0, GFP_KERNEL);
+ if (!cdev->midi_out_urb) {
+ usb_free_urb(cdev->ep1_in_urb);
+ cdev->ep1_in_urb = NULL;
+ return -ENOMEM;
+ }
+ usb_init_urb(cdev->ep1_in_urb);
+ usb_init_urb(cdev->midi_out_urb);
+
+ usb_fill_bulk_urb(cdev->ep1_in_urb, usb_dev,
usb_rcvbulkpipe(usb_dev, 0x1),
cdev->ep1_in_buf, EP1_BUFSIZE,
usb_ep1_command_reply_dispatch, cdev);
- usb_fill_bulk_urb(&cdev->midi_out_urb, usb_dev,
+ usb_fill_bulk_urb(cdev->midi_out_urb, usb_dev,
usb_sndbulkpipe(usb_dev, 0x1),
cdev->midi_out_buf, EP1_BUFSIZE,
snd_usb_caiaq_midi_output_done, cdev);
/* sanity checks of EPs before actually submitting */
- if (usb_urb_ep_type_check(&cdev->ep1_in_urb) ||
- usb_urb_ep_type_check(&cdev->midi_out_urb)) {
+ if (usb_urb_ep_type_check(cdev->ep1_in_urb) ||
+ usb_urb_ep_type_check(cdev->midi_out_urb)) {
dev_err(dev, "invalid EPs\n");
return -EINVAL;
}
@@ -480,7 +494,7 @@ static int init_card(struct snd_usb_caiaqdev *cdev)
init_waitqueue_head(&cdev->ep1_wait_queue);
init_waitqueue_head(&cdev->prepare_wait_queue);
- if (usb_submit_urb(&cdev->ep1_in_urb, GFP_KERNEL) != 0)
+ if (usb_submit_urb(cdev->ep1_in_urb, GFP_KERNEL) != 0)
return -EIO;
err = snd_usb_caiaq_send_command(cdev, EP1_CMD_GET_DEVICE_INFO, NULL, 0);
@@ -530,7 +544,7 @@ static int init_card(struct snd_usb_caiaqdev *cdev)
return 0;
err_kill_urb:
- usb_kill_urb(&cdev->ep1_in_urb);
+ usb_kill_urb(cdev->ep1_in_urb);
return err;
}
@@ -576,8 +590,8 @@ static void snd_disconnect(struct usb_interface *intf)
#endif
snd_usb_caiaq_audio_disconnect(cdev);
- usb_kill_urb(&cdev->ep1_in_urb);
- usb_kill_urb(&cdev->midi_out_urb);
+ usb_kill_urb(cdev->ep1_in_urb);
+ usb_kill_urb(cdev->midi_out_urb);
snd_card_free_when_closed(card);
}
diff --git a/sound/usb/caiaq/device.h b/sound/usb/caiaq/device.h
index 743eb0387b5f..1c6f34693fa8 100644
--- a/sound/usb/caiaq/device.h
+++ b/sound/usb/caiaq/device.h
@@ -60,8 +60,8 @@ struct snd_usb_caiaq_cb_info;
struct snd_usb_caiaqdev {
struct snd_usb_audio chip;
- struct urb ep1_in_urb;
- struct urb midi_out_urb;
+ struct urb *ep1_in_urb;
+ struct urb *midi_out_urb;
struct urb **data_urbs_in;
struct urb **data_urbs_out;
struct snd_usb_caiaq_cb_info *data_cb_info;
diff --git a/sound/usb/caiaq/midi.c b/sound/usb/caiaq/midi.c
index c656d0162432..18529484c8dc 100644
--- a/sound/usb/caiaq/midi.c
+++ b/sound/usb/caiaq/midi.c
@@ -43,7 +43,7 @@ static int snd_usb_caiaq_midi_output_close(struct snd_rawmidi_substream *substre
{
struct snd_usb_caiaqdev *cdev = substream->rmidi->private_data;
if (cdev->midi_out_active) {
- usb_kill_urb(&cdev->midi_out_urb);
+ usb_kill_urb(cdev->midi_out_urb);
cdev->midi_out_active = 0;
}
return 0;
@@ -64,9 +64,9 @@ static void snd_usb_caiaq_midi_send(struct snd_usb_caiaqdev *cdev,
return;
cdev->midi_out_buf[2] = len;
- cdev->midi_out_urb.transfer_buffer_length = len+3;
+ cdev->midi_out_urb->transfer_buffer_length = len+3;
- ret = usb_submit_urb(&cdev->midi_out_urb, GFP_ATOMIC);
+ ret = usb_submit_urb(cdev->midi_out_urb, GFP_ATOMIC);
if (ret < 0)
dev_err(dev,
"snd_usb_caiaq_midi_send(%p): usb_submit_urb() failed,"
--
2.43.0The epq_in_urb object belonging to the caiaq device is coupled within
the struct snd_usb_caiaqdev. After usb_submit_urb(epq_in_urb, GFP_KERNEL)
executes successfully, epq_in_urb is successfully added to the urbp_list
queue of the dummy HCD driver (userspace specifies dummy_hcd as the HCD
layer driver for the caiaq USB device).
When init_card() calls snd_usb_caiaq_send_command() which subsequently
fails due to a timeout, and proceeds to call snd_card_free() to release
the card, the embedded ep1_in_urb object is also freed. When the dummy
HCD driver detects that the URB has been unlinked, it returns the URB
(by usb_hcd_giveback_urb()), which triggers [1].
Decouple the ep1_in_urb object from the struct snd_usb_caiaqdev and switch
to using a pointer instead. Separately allocate and manage the memory for
ep1_in_urb to prevent the release of the snd_card memory object from
interfering with it.
midi_out_urb has the same issue as ep1_in_urb and is handled in the same
way.
[1]
BUG: KASAN: slab-use-after-free in usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96
Write of size 4 at addr ffff88803cee1050 by task ktimers/1/29
Call Trace:
usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96
dummy_timer+0xaac/0x4d50 drivers/usb/gadget/udc/dummy_hcd.c:2019
__run_hrtimer kernel/time/hrtimer.c:2067 [inline]
__hrtimer_run_queues+0x3eb/0xaf0 kernel/time/hrtimer.c:2124
hrtimer_run_softirq+0x1e1/0x2e0 kernel/time/hrtimer.c:2141
Allocated by task 36:
snd_card_new+0x7b/0x110 sound/core/init.c:184
create_card sound/usb/caiaq/device.c:429 [inline]
snd_probe+0x236/0x1af0 sound/usb/caiaq/device.c:544
Freed by task 36:
snd_card_free_when_closed sound/core/init.c:630 [inline]
snd_card_free+0x138/0x1d0 sound/core/init.c:662
snd_probe+0x162b/0x1af0 sound/usb/caiaq/device.c:553
Fixes: 523f1dce3743 ("[ALSA] Add Native Instrument usb audio device support")
Reported-by: syzbot+832ce9fa3face1b7d44d@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=832ce9fa3face1b7d44d
Tested-by: syzbot+832ce9fa3face1b7d44d@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@sina.com>
---
v1 -> v2: same dealwith midi_out_urb and add missing check
v2 -> v3: set ep1_in_urb to NULL after midi_out_urb allow failed
remove err message when alloc failed
v3 -> v4: remove usb_init_urb() after use usb_alloc_urb
sound/usb/caiaq/device.c | 36 ++++++++++++++++++++++++------------
sound/usb/caiaq/device.h | 4 ++--
sound/usb/caiaq/midi.c | 6 +++---
3 files changed, 29 insertions(+), 17 deletions(-)
diff --git a/sound/usb/caiaq/device.c b/sound/usb/caiaq/device.c
index a16e59248480..3d821fde4582 100644
--- a/sound/usb/caiaq/device.c
+++ b/sound/usb/caiaq/device.c
@@ -192,8 +192,8 @@ static void usb_ep1_command_reply_dispatch (struct urb* urb)
break;
}
- cdev->ep1_in_urb.actual_length = 0;
- ret = usb_submit_urb(&cdev->ep1_in_urb, GFP_ATOMIC);
+ cdev->ep1_in_urb->actual_length = 0;
+ ret = usb_submit_urb(cdev->ep1_in_urb, GFP_ATOMIC);
if (ret < 0)
dev_err(dev, "unable to submit urb. OOM!?\n");
}
@@ -408,6 +408,10 @@ static void card_free(struct snd_card *card)
#endif
snd_usb_caiaq_audio_free(cdev);
usb_put_dev(cdev->chip.dev);
+ usb_free_urb(cdev->ep1_in_urb);
+ cdev->ep1_in_urb = NULL;
+ usb_free_urb(cdev->midi_out_urb);
+ cdev->midi_out_urb = NULL;
}
static int create_card(struct usb_device *usb_dev,
@@ -457,22 +461,30 @@ static int init_card(struct snd_usb_caiaqdev *cdev)
return -EIO;
}
- usb_init_urb(&cdev->ep1_in_urb);
- usb_init_urb(&cdev->midi_out_urb);
+ cdev->ep1_in_urb = usb_alloc_urb(0, GFP_KERNEL);
+ if (!cdev->ep1_in_urb)
+ return -ENOMEM;
- usb_fill_bulk_urb(&cdev->ep1_in_urb, usb_dev,
+ cdev->midi_out_urb = usb_alloc_urb(0, GFP_KERNEL);
+ if (!cdev->midi_out_urb) {
+ usb_free_urb(cdev->ep1_in_urb);
+ cdev->ep1_in_urb = NULL;
+ return -ENOMEM;
+ }
+
+ usb_fill_bulk_urb(cdev->ep1_in_urb, usb_dev,
usb_rcvbulkpipe(usb_dev, 0x1),
cdev->ep1_in_buf, EP1_BUFSIZE,
usb_ep1_command_reply_dispatch, cdev);
- usb_fill_bulk_urb(&cdev->midi_out_urb, usb_dev,
+ usb_fill_bulk_urb(cdev->midi_out_urb, usb_dev,
usb_sndbulkpipe(usb_dev, 0x1),
cdev->midi_out_buf, EP1_BUFSIZE,
snd_usb_caiaq_midi_output_done, cdev);
/* sanity checks of EPs before actually submitting */
- if (usb_urb_ep_type_check(&cdev->ep1_in_urb) ||
- usb_urb_ep_type_check(&cdev->midi_out_urb)) {
+ if (usb_urb_ep_type_check(cdev->ep1_in_urb) ||
+ usb_urb_ep_type_check(cdev->midi_out_urb)) {
dev_err(dev, "invalid EPs\n");
return -EINVAL;
}
@@ -480,7 +492,7 @@ static int init_card(struct snd_usb_caiaqdev *cdev)
init_waitqueue_head(&cdev->ep1_wait_queue);
init_waitqueue_head(&cdev->prepare_wait_queue);
- if (usb_submit_urb(&cdev->ep1_in_urb, GFP_KERNEL) != 0)
+ if (usb_submit_urb(cdev->ep1_in_urb, GFP_KERNEL) != 0)
return -EIO;
err = snd_usb_caiaq_send_command(cdev, EP1_CMD_GET_DEVICE_INFO, NULL, 0);
@@ -530,7 +542,7 @@ static int init_card(struct snd_usb_caiaqdev *cdev)
return 0;
err_kill_urb:
- usb_kill_urb(&cdev->ep1_in_urb);
+ usb_kill_urb(cdev->ep1_in_urb);
return err;
}
@@ -576,8 +588,8 @@ static void snd_disconnect(struct usb_interface *intf)
#endif
snd_usb_caiaq_audio_disconnect(cdev);
- usb_kill_urb(&cdev->ep1_in_urb);
- usb_kill_urb(&cdev->midi_out_urb);
+ usb_kill_urb(cdev->ep1_in_urb);
+ usb_kill_urb(cdev->midi_out_urb);
snd_card_free_when_closed(card);
}
diff --git a/sound/usb/caiaq/device.h b/sound/usb/caiaq/device.h
index 743eb0387b5f..1c6f34693fa8 100644
--- a/sound/usb/caiaq/device.h
+++ b/sound/usb/caiaq/device.h
@@ -60,8 +60,8 @@ struct snd_usb_caiaq_cb_info;
struct snd_usb_caiaqdev {
struct snd_usb_audio chip;
- struct urb ep1_in_urb;
- struct urb midi_out_urb;
+ struct urb *ep1_in_urb;
+ struct urb *midi_out_urb;
struct urb **data_urbs_in;
struct urb **data_urbs_out;
struct snd_usb_caiaq_cb_info *data_cb_info;
diff --git a/sound/usb/caiaq/midi.c b/sound/usb/caiaq/midi.c
index c656d0162432..18529484c8dc 100644
--- a/sound/usb/caiaq/midi.c
+++ b/sound/usb/caiaq/midi.c
@@ -43,7 +43,7 @@ static int snd_usb_caiaq_midi_output_close(struct snd_rawmidi_substream *substre
{
struct snd_usb_caiaqdev *cdev = substream->rmidi->private_data;
if (cdev->midi_out_active) {
- usb_kill_urb(&cdev->midi_out_urb);
+ usb_kill_urb(cdev->midi_out_urb);
cdev->midi_out_active = 0;
}
return 0;
@@ -64,9 +64,9 @@ static void snd_usb_caiaq_midi_send(struct snd_usb_caiaqdev *cdev,
return;
cdev->midi_out_buf[2] = len;
- cdev->midi_out_urb.transfer_buffer_length = len+3;
+ cdev->midi_out_urb->transfer_buffer_length = len+3;
- ret = usb_submit_urb(&cdev->midi_out_urb, GFP_ATOMIC);
+ ret = usb_submit_urb(cdev->midi_out_urb, GFP_ATOMIC);
if (ret < 0)
dev_err(dev,
"snd_usb_caiaq_midi_send(%p): usb_submit_urb() failed,"
--
2.43.0On Thu, 03 Sep 2026 15:05:21 +0200,
Edward Adam Davis wrote:
>
> The epq_in_urb object belonging to the caiaq device is coupled within
> the struct snd_usb_caiaqdev. After usb_submit_urb(epq_in_urb, GFP_KERNEL)
> executes successfully, epq_in_urb is successfully added to the urbp_list
> queue of the dummy HCD driver (userspace specifies dummy_hcd as the HCD
> layer driver for the caiaq USB device).
>
> When init_card() calls snd_usb_caiaq_send_command() which subsequently
> fails due to a timeout, and proceeds to call snd_card_free() to release
> the card, the embedded ep1_in_urb object is also freed. When the dummy
> HCD driver detects that the URB has been unlinked, it returns the URB
> (by usb_hcd_giveback_urb()), which triggers [1].
>
> Decouple the ep1_in_urb object from the struct snd_usb_caiaqdev and switch
> to using a pointer instead. Separately allocate and manage the memory for
> ep1_in_urb to prevent the release of the snd_card memory object from
> interfering with it.
>
> midi_out_urb has the same issue as ep1_in_urb and is handled in the same
> way.
>
> [1]
> BUG: KASAN: slab-use-after-free in usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96
> Write of size 4 at addr ffff88803cee1050 by task ktimers/1/29
> Call Trace:
> usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96
> dummy_timer+0xaac/0x4d50 drivers/usb/gadget/udc/dummy_hcd.c:2019
> __run_hrtimer kernel/time/hrtimer.c:2067 [inline]
> __hrtimer_run_queues+0x3eb/0xaf0 kernel/time/hrtimer.c:2124
> hrtimer_run_softirq+0x1e1/0x2e0 kernel/time/hrtimer.c:2141
>
> Allocated by task 36:
> snd_card_new+0x7b/0x110 sound/core/init.c:184
> create_card sound/usb/caiaq/device.c:429 [inline]
> snd_probe+0x236/0x1af0 sound/usb/caiaq/device.c:544
>
> Freed by task 36:
> snd_card_free_when_closed sound/core/init.c:630 [inline]
> snd_card_free+0x138/0x1d0 sound/core/init.c:662
> snd_probe+0x162b/0x1af0 sound/usb/caiaq/device.c:553
>
> Fixes: 523f1dce3743 ("[ALSA] Add Native Instrument usb audio device support")
> Reported-by: syzbot+832ce9fa3face1b7d44d@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=832ce9fa3face1b7d44d
> Tested-by: syzbot+832ce9fa3face1b7d44d@syzkaller.appspotmail.com
> Signed-off-by: Edward Adam Davis <eadavis@sina.com>
Applied now. Thanks.
Takashi
The epq_in_urb object belonging to the caiaq device is coupled within
the struct snd_usb_caiaqdev. After usb_submit_urb(epq_in_urb, GFP_KERNEL)
executes successfully, epq_in_urb is successfully added to the urbp_list
queue of the dummy HCD driver (userspace specifies dummy_hcd as the HCD
layer driver for the caiaq USB device).
When init_card() calls snd_usb_caiaq_send_command() which subsequently
fails due to a timeout, and proceeds to call snd_card_free() to release
the card, the embedded ep1_in_urb object is also freed. When the dummy
HCD driver detects that the URB has been unlinked, it returns the URB
(by usb_hcd_giveback_urb()), which triggers [1].
Decouple the ep1_in_urb object from the struct snd_usb_caiaqdev and switch
to using a pointer instead. Separately allocate and manage the memory for
ep1_in_urb to prevent the release of the snd_card memory object from
interfering with it.
midi_out_urb has the same issue as ep1_in_urb and is handled in the same
way.
[1]
BUG: KASAN: slab-use-after-free in usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96
Write of size 4 at addr ffff88803cee1050 by task ktimers/1/29
Call Trace:
usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96
dummy_timer+0xaac/0x4d50 drivers/usb/gadget/udc/dummy_hcd.c:2019
__run_hrtimer kernel/time/hrtimer.c:2067 [inline]
__hrtimer_run_queues+0x3eb/0xaf0 kernel/time/hrtimer.c:2124
hrtimer_run_softirq+0x1e1/0x2e0 kernel/time/hrtimer.c:2141
Allocated by task 36:
snd_card_new+0x7b/0x110 sound/core/init.c:184
create_card sound/usb/caiaq/device.c:429 [inline]
snd_probe+0x236/0x1af0 sound/usb/caiaq/device.c:544
Freed by task 36:
snd_card_free_when_closed sound/core/init.c:630 [inline]
snd_card_free+0x138/0x1d0 sound/core/init.c:662
snd_probe+0x162b/0x1af0 sound/usb/caiaq/device.c:553
Fixes: 523f1dce3743 ("[ALSA] Add Native Instrument usb audio device support")
Reported-by: syzbot+832ce9fa3face1b7d44d@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=832ce9fa3face1b7d44d
Tested-by: syzbot+832ce9fa3face1b7d44d@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@sina.com>
---
v1 -> v2: same dealwith midi_out_urb and add missing check
sound/usb/caiaq/device.c | 39 +++++++++++++++++++++++++++------------
sound/usb/caiaq/device.h | 4 ++--
sound/usb/caiaq/midi.c | 6 +++---
3 files changed, 32 insertions(+), 17 deletions(-)
diff --git a/sound/usb/caiaq/device.c b/sound/usb/caiaq/device.c
index a16e59248480..d0fe954b8133 100644
--- a/sound/usb/caiaq/device.c
+++ b/sound/usb/caiaq/device.c
@@ -192,8 +192,8 @@ static void usb_ep1_command_reply_dispatch (struct urb* urb)
break;
}
- cdev->ep1_in_urb.actual_length = 0;
- ret = usb_submit_urb(&cdev->ep1_in_urb, GFP_ATOMIC);
+ cdev->ep1_in_urb->actual_length = 0;
+ ret = usb_submit_urb(cdev->ep1_in_urb, GFP_ATOMIC);
if (ret < 0)
dev_err(dev, "unable to submit urb. OOM!?\n");
}
@@ -408,6 +408,10 @@ static void card_free(struct snd_card *card)
#endif
snd_usb_caiaq_audio_free(cdev);
usb_put_dev(cdev->chip.dev);
+ usb_free_urb(cdev->ep1_in_urb);
+ cdev->ep1_in_urb = NULL;
+ usb_free_urb(cdev->midi_out_urb);
+ cdev->midi_out_urb = NULL;
}
static int create_card(struct usb_device *usb_dev,
@@ -457,22 +461,33 @@ static int init_card(struct snd_usb_caiaqdev *cdev)
return -EIO;
}
- usb_init_urb(&cdev->ep1_in_urb);
- usb_init_urb(&cdev->midi_out_urb);
+ cdev->ep1_in_urb = usb_alloc_urb(0, GFP_KERNEL);
+ if (!cdev->ep1_in_urb) {
+ dev_err(dev, "alloc ep1_in_urb failed.\n");
+ return -ENOMEM;
+ }
+ cdev->midi_out_urb = usb_alloc_urb(0, GFP_KERNEL);
+ if (!cdev->midi_out_urb) {
+ usb_free_urb(cdev->ep1_in_urb);
+ dev_err(dev, "alloc midi_out_urb failed.\n");
+ return -ENOMEM;
+ }
+ usb_init_urb(cdev->ep1_in_urb);
+ usb_init_urb(cdev->midi_out_urb);
- usb_fill_bulk_urb(&cdev->ep1_in_urb, usb_dev,
+ usb_fill_bulk_urb(cdev->ep1_in_urb, usb_dev,
usb_rcvbulkpipe(usb_dev, 0x1),
cdev->ep1_in_buf, EP1_BUFSIZE,
usb_ep1_command_reply_dispatch, cdev);
- usb_fill_bulk_urb(&cdev->midi_out_urb, usb_dev,
+ usb_fill_bulk_urb(cdev->midi_out_urb, usb_dev,
usb_sndbulkpipe(usb_dev, 0x1),
cdev->midi_out_buf, EP1_BUFSIZE,
snd_usb_caiaq_midi_output_done, cdev);
/* sanity checks of EPs before actually submitting */
- if (usb_urb_ep_type_check(&cdev->ep1_in_urb) ||
- usb_urb_ep_type_check(&cdev->midi_out_urb)) {
+ if (usb_urb_ep_type_check(cdev->ep1_in_urb) ||
+ usb_urb_ep_type_check(cdev->midi_out_urb)) {
dev_err(dev, "invalid EPs\n");
return -EINVAL;
}
@@ -480,7 +495,7 @@ static int init_card(struct snd_usb_caiaqdev *cdev)
init_waitqueue_head(&cdev->ep1_wait_queue);
init_waitqueue_head(&cdev->prepare_wait_queue);
- if (usb_submit_urb(&cdev->ep1_in_urb, GFP_KERNEL) != 0)
+ if (usb_submit_urb(cdev->ep1_in_urb, GFP_KERNEL) != 0)
return -EIO;
err = snd_usb_caiaq_send_command(cdev, EP1_CMD_GET_DEVICE_INFO, NULL, 0);
@@ -530,7 +545,7 @@ static int init_card(struct snd_usb_caiaqdev *cdev)
return 0;
err_kill_urb:
- usb_kill_urb(&cdev->ep1_in_urb);
+ usb_kill_urb(cdev->ep1_in_urb);
return err;
}
@@ -576,8 +591,8 @@ static void snd_disconnect(struct usb_interface *intf)
#endif
snd_usb_caiaq_audio_disconnect(cdev);
- usb_kill_urb(&cdev->ep1_in_urb);
- usb_kill_urb(&cdev->midi_out_urb);
+ usb_kill_urb(cdev->ep1_in_urb);
+ usb_kill_urb(cdev->midi_out_urb);
snd_card_free_when_closed(card);
}
diff --git a/sound/usb/caiaq/device.h b/sound/usb/caiaq/device.h
index 743eb0387b5f..1c6f34693fa8 100644
--- a/sound/usb/caiaq/device.h
+++ b/sound/usb/caiaq/device.h
@@ -60,8 +60,8 @@ struct snd_usb_caiaq_cb_info;
struct snd_usb_caiaqdev {
struct snd_usb_audio chip;
- struct urb ep1_in_urb;
- struct urb midi_out_urb;
+ struct urb *ep1_in_urb;
+ struct urb *midi_out_urb;
struct urb **data_urbs_in;
struct urb **data_urbs_out;
struct snd_usb_caiaq_cb_info *data_cb_info;
diff --git a/sound/usb/caiaq/midi.c b/sound/usb/caiaq/midi.c
index c656d0162432..18529484c8dc 100644
--- a/sound/usb/caiaq/midi.c
+++ b/sound/usb/caiaq/midi.c
@@ -43,7 +43,7 @@ static int snd_usb_caiaq_midi_output_close(struct snd_rawmidi_substream *substre
{
struct snd_usb_caiaqdev *cdev = substream->rmidi->private_data;
if (cdev->midi_out_active) {
- usb_kill_urb(&cdev->midi_out_urb);
+ usb_kill_urb(cdev->midi_out_urb);
cdev->midi_out_active = 0;
}
return 0;
@@ -64,9 +64,9 @@ static void snd_usb_caiaq_midi_send(struct snd_usb_caiaqdev *cdev,
return;
cdev->midi_out_buf[2] = len;
- cdev->midi_out_urb.transfer_buffer_length = len+3;
+ cdev->midi_out_urb->transfer_buffer_length = len+3;
- ret = usb_submit_urb(&cdev->midi_out_urb, GFP_ATOMIC);
+ ret = usb_submit_urb(cdev->midi_out_urb, GFP_ATOMIC);
if (ret < 0)
dev_err(dev,
"snd_usb_caiaq_midi_send(%p): usb_submit_urb() failed,"
--
2.43.0On Thu, 3 Sep 2026 18:04:10 +0800, Edward Adam Davis wrote:
> The epq_in_urb object belonging to the caiaq device is coupled within
> the struct snd_usb_caiaqdev. After usb_submit_urb(epq_in_urb, GFP_KERNEL)
> executes successfully, epq_in_urb is successfully added to the urbp_list
> queue of the dummy HCD driver (userspace specifies dummy_hcd as the HCD
> layer driver for the caiaq USB device).
Sounds like an irrelevant detail. Same crash would happen with any HCD.
> When init_card() calls snd_usb_caiaq_send_command() which subsequently
> fails due to a timeout, and proceeds to call snd_card_free() to release
> the card, the embedded ep1_in_urb object is also freed. When the dummy
> HCD driver detects that the URB has been unlinked, it returns the URB
> (by usb_hcd_giveback_urb()), which triggers [1].
>
> Decouple the ep1_in_urb object from the struct snd_usb_caiaqdev and switch
> to using a pointer instead. Separately allocate and manage the memory for
> ep1_in_urb to prevent the release of the snd_card memory object from
> interfering with it.
>
> midi_out_urb has the same issue as ep1_in_urb and is handled in the same
> way.
>
> [1]
> BUG: KASAN: slab-use-after-free in usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96
> Write of size 4 at addr ffff88803cee1050 by task ktimers/1/29
> Call Trace:
> usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96
> dummy_timer+0xaac/0x4d50 drivers/usb/gadget/udc/dummy_hcd.c:2019
> __run_hrtimer kernel/time/hrtimer.c:2067 [inline]
> __hrtimer_run_queues+0x3eb/0xaf0 kernel/time/hrtimer.c:2124
> hrtimer_run_softirq+0x1e1/0x2e0 kernel/time/hrtimer.c:2141
>
> Allocated by task 36:
> snd_card_new+0x7b/0x110 sound/core/init.c:184
> create_card sound/usb/caiaq/device.c:429 [inline]
> snd_probe+0x236/0x1af0 sound/usb/caiaq/device.c:544
>
> Freed by task 36:
> snd_card_free_when_closed sound/core/init.c:630 [inline]
> snd_card_free+0x138/0x1d0 sound/core/init.c:662
> snd_probe+0x162b/0x1af0 sound/usb/caiaq/device.c:553
>
> Fixes: 523f1dce3743 ("[ALSA] Add Native Instrument usb audio device support")
> Reported-by: syzbot+832ce9fa3face1b7d44d@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=832ce9fa3face1b7d44d
> Tested-by: syzbot+832ce9fa3face1b7d44d@syzkaller.appspotmail.com
> Signed-off-by: Edward Adam Davis <eadavis@sina.com>
> ---
Does this submission comply with the rules here?
https://docs.kernel.org/process/coding-assistants.html
> v1 -> v2: same dealwith midi_out_urb and add missing check
>
> sound/usb/caiaq/device.c | 39 +++++++++++++++++++++++++++------------
> sound/usb/caiaq/device.h | 4 ++--
> sound/usb/caiaq/midi.c | 6 +++---
> 3 files changed, 32 insertions(+), 17 deletions(-)
>
> diff --git a/sound/usb/caiaq/device.c b/sound/usb/caiaq/device.c
> index a16e59248480..d0fe954b8133 100644
> --- a/sound/usb/caiaq/device.c
> +++ b/sound/usb/caiaq/device.c
> @@ -192,8 +192,8 @@ static void usb_ep1_command_reply_dispatch (struct urb* urb)
> break;
> }
>
> - cdev->ep1_in_urb.actual_length = 0;
> - ret = usb_submit_urb(&cdev->ep1_in_urb, GFP_ATOMIC);
> + cdev->ep1_in_urb->actual_length = 0;
That's one of the first things usb_submit_urb() below would do,
and has done since forever.
> + ret = usb_submit_urb(cdev->ep1_in_urb, GFP_ATOMIC);
> if (ret < 0)
> dev_err(dev, "unable to submit urb. OOM!?\n");
> }
> @@ -408,6 +408,10 @@ static void card_free(struct snd_card *card)
> #endif
> snd_usb_caiaq_audio_free(cdev);
> usb_put_dev(cdev->chip.dev);
> + usb_free_urb(cdev->ep1_in_urb);
> + cdev->ep1_in_urb = NULL;
> + usb_free_urb(cdev->midi_out_urb);
> + cdev->midi_out_urb = NULL;
Is clearing this necessary? (I'm not familiar with ALSA)
> }
>
> static int create_card(struct usb_device *usb_dev,
> @@ -457,22 +461,33 @@ static int init_card(struct snd_usb_caiaqdev *cdev)
> return -EIO;
> }
>
> - usb_init_urb(&cdev->ep1_in_urb);
> - usb_init_urb(&cdev->midi_out_urb);
> + cdev->ep1_in_urb = usb_alloc_urb(0, GFP_KERNEL);
> + if (!cdev->ep1_in_urb) {
> + dev_err(dev, "alloc ep1_in_urb failed.\n");
AFAIK logging on allocation failure is frowned upon.
> + return -ENOMEM;
> + }
> + cdev->midi_out_urb = usb_alloc_urb(0, GFP_KERNEL);
> + if (!cdev->midi_out_urb) {
> + usb_free_urb(cdev->ep1_in_urb);
> + dev_err(dev, "alloc midi_out_urb failed.\n");
> + return -ENOMEM;
> + }
> + usb_init_urb(cdev->ep1_in_urb);
> + usb_init_urb(cdev->midi_out_urb);
And what would be the point of that?
>
> - usb_fill_bulk_urb(&cdev->ep1_in_urb, usb_dev,
> + usb_fill_bulk_urb(cdev->ep1_in_urb, usb_dev,
> usb_rcvbulkpipe(usb_dev, 0x1),
> cdev->ep1_in_buf, EP1_BUFSIZE,
> usb_ep1_command_reply_dispatch, cdev);
>
> - usb_fill_bulk_urb(&cdev->midi_out_urb, usb_dev,
> + usb_fill_bulk_urb(cdev->midi_out_urb, usb_dev,
> usb_sndbulkpipe(usb_dev, 0x1),
> cdev->midi_out_buf, EP1_BUFSIZE,
> snd_usb_caiaq_midi_output_done, cdev);
>
> /* sanity checks of EPs before actually submitting */
> - if (usb_urb_ep_type_check(&cdev->ep1_in_urb) ||
> - usb_urb_ep_type_check(&cdev->midi_out_urb)) {
> + if (usb_urb_ep_type_check(cdev->ep1_in_urb) ||
> + usb_urb_ep_type_check(cdev->midi_out_urb)) {
> dev_err(dev, "invalid EPs\n");
> return -EINVAL;
> }
> @@ -480,7 +495,7 @@ static int init_card(struct snd_usb_caiaqdev *cdev)
> init_waitqueue_head(&cdev->ep1_wait_queue);
> init_waitqueue_head(&cdev->prepare_wait_queue);
>
> - if (usb_submit_urb(&cdev->ep1_in_urb, GFP_KERNEL) != 0)
> + if (usb_submit_urb(cdev->ep1_in_urb, GFP_KERNEL) != 0)
> return -EIO;
>
> err = snd_usb_caiaq_send_command(cdev, EP1_CMD_GET_DEVICE_INFO, NULL, 0);
> @@ -530,7 +545,7 @@ static int init_card(struct snd_usb_caiaqdev *cdev)
> return 0;
>
> err_kill_urb:
> - usb_kill_urb(&cdev->ep1_in_urb);
> + usb_kill_urb(cdev->ep1_in_urb);
> return err;
> }
>
> @@ -576,8 +591,8 @@ static void snd_disconnect(struct usb_interface *intf)
> #endif
> snd_usb_caiaq_audio_disconnect(cdev);
>
> - usb_kill_urb(&cdev->ep1_in_urb);
> - usb_kill_urb(&cdev->midi_out_urb);
> + usb_kill_urb(cdev->ep1_in_urb);
> + usb_kill_urb(cdev->midi_out_urb);
>
> snd_card_free_when_closed(card);
> }
> diff --git a/sound/usb/caiaq/device.h b/sound/usb/caiaq/device.h
> index 743eb0387b5f..1c6f34693fa8 100644
> --- a/sound/usb/caiaq/device.h
> +++ b/sound/usb/caiaq/device.h
> @@ -60,8 +60,8 @@ struct snd_usb_caiaq_cb_info;
> struct snd_usb_caiaqdev {
> struct snd_usb_audio chip;
>
> - struct urb ep1_in_urb;
> - struct urb midi_out_urb;
> + struct urb *ep1_in_urb;
> + struct urb *midi_out_urb;
> struct urb **data_urbs_in;
> struct urb **data_urbs_out;
> struct snd_usb_caiaq_cb_info *data_cb_info;
> diff --git a/sound/usb/caiaq/midi.c b/sound/usb/caiaq/midi.c
> index c656d0162432..18529484c8dc 100644
> --- a/sound/usb/caiaq/midi.c
> +++ b/sound/usb/caiaq/midi.c
> @@ -43,7 +43,7 @@ static int snd_usb_caiaq_midi_output_close(struct snd_rawmidi_substream *substre
> {
> struct snd_usb_caiaqdev *cdev = substream->rmidi->private_data;
> if (cdev->midi_out_active) {
> - usb_kill_urb(&cdev->midi_out_urb);
> + usb_kill_urb(cdev->midi_out_urb);
> cdev->midi_out_active = 0;
> }
> return 0;
> @@ -64,9 +64,9 @@ static void snd_usb_caiaq_midi_send(struct snd_usb_caiaqdev *cdev,
> return;
>
> cdev->midi_out_buf[2] = len;
> - cdev->midi_out_urb.transfer_buffer_length = len+3;
> + cdev->midi_out_urb->transfer_buffer_length = len+3;
>
> - ret = usb_submit_urb(&cdev->midi_out_urb, GFP_ATOMIC);
> + ret = usb_submit_urb(cdev->midi_out_urb, GFP_ATOMIC);
> if (ret < 0)
> dev_err(dev,
> "snd_usb_caiaq_midi_send(%p): usb_submit_urb() failed,"
> --
> 2.43.0
>
© 2016 - 2026 Red Hat, Inc.