kernel/linux.git/drivers/usb, branch v6.1.168

usb: gadget: f_uac1_legacy: validate control request size

2026-04-11T12:16:34+00:00

commit 6e0e34d85cd46ceb37d16054e97a373a32770f6c upstream. f_audio_complete() copies req->length bytes into a 4-byte stack variable: u32 data = 0; memcpy(&data, req->buf, req->length); req->length is derived from the host-controlled USB request path, which can lead to a stack out-of-bounds write. Validate req->actual against the expected payload size for the supported control selectors and decode only the expected amount of data. This avoids copying a host-influenced length into a fixed-size stack object. Signed-off-by: Taegu Ha Cc: stable Link: https://patch.msgid.link/20260401191311.3604898-1-hataegu0826@gmail.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_rndis: Protect RNDIS options with mutex

2026-04-11T12:16:34+00:00

commit 8d8c68b1fc06ece60cf43e1306ff0f4ac121547e upstream. The class/subclass/protocol options are suspectible to race conditions as they can be accessed concurrently through configfs. Use existing mutex to protect these options. This issue was identified during code inspection. Fixes: 73517cf49bd4 ("usb: gadget: add RNDIS configfs options for class/subclass/protocol") Cc: stable@vger.kernel.org Signed-off-by: Kuen-Han Tsai Link: https://patch.msgid.link/20260320-usb-net-lifecycle-v1-2-4886b578161b@google.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_subset: Fix unbalanced refcnt in geth_free

2026-04-11T12:16:33+00:00

commit caa27923aacd8a5869207842f2ab1657c6c0c7bc upstream. geth_alloc() increments the reference count, but geth_free() fails to decrement it. This prevents the configuration of attributes via configfs after unlinking the function. Decrement the reference count in geth_free() to ensure proper cleanup. Fixes: 02832e56f88a ("usb: gadget: f_subset: add configfs support") Cc: stable@vger.kernel.org Signed-off-by: Kuen-Han Tsai Link: https://patch.msgid.link/20260320-usb-net-lifecycle-v1-1-4886b578161b@google.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: uvc: fix NULL pointer dereference during unbind race

2026-04-11T12:16:33+00:00

commit eba2936bbe6b752a31725a9eb5c674ecbf21ee7d upstream. Commit b81ac4395bbe ("usb: gadget: uvc: allow for application to cleanly shutdown") introduced two stages of synchronization waits totaling 1500ms in uvc_function_unbind() to prevent several types of kernel panics. However, this timing-based approach is insufficient during power management (PM) transitions. When the PM subsystem starts freezing user space processes, the wait_event_interruptible_timeout() is aborted early, which allows the unbind thread to proceed and nullify the gadget pointer (cdev->gadget = NULL): [ 814.123447][ T947] configfs-gadget.g1 gadget.0: uvc: uvc_function_unbind() [ 814.178583][ T3173] PM: suspend entry (deep) [ 814.192487][ T3173] Freezing user space processes [ 814.197668][ T947] configfs-gadget.g1 gadget.0: uvc: uvc_function_unbind no clean disconnect, wait for release When the PM subsystem resumes or aborts the suspend and tasks are restarted, the V4L2 release path is executed and attempts to access the already nullified gadget pointer, triggering a kernel panic: [ 814.292597][ C0] PM: pm_system_irq_wakeup: 479 triggered dhdpcie_host_wake [ 814.386727][ T3173] Restarting tasks ... [ 814.403522][ T4558] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000030 [ 814.404021][ T4558] pc : usb_gadget_deactivate+0x14/0xf4 [ 814.404031][ T4558] lr : usb_function_deactivate+0x54/0x94 [ 814.404078][ T4558] Call trace: [ 814.404080][ T4558] usb_gadget_deactivate+0x14/0xf4 [ 814.404083][ T4558] usb_function_deactivate+0x54/0x94 [ 814.404087][ T4558] uvc_function_disconnect+0x1c/0x5c [ 814.404092][ T4558] uvc_v4l2_release+0x44/0xac [ 814.404095][ T4558] v4l2_release+0xcc/0x130 Address the race condition and NULL pointer dereference by: 1. State Synchronization (flag + mutex) Introduce a 'func_unbound' flag in struct uvc_device. This allows uvc_function_disconnect() to safely skip accessing the nullified cdev->gadget pointer. As suggested by Alan Stern, this flag is protected by a new mutex (uvc->lock) to ensure proper memory ordering and prevent instruction reordering or speculative loads. This mutex is also used to protect 'func_connected' for consistent state management. 2. Explicit Synchronization (completion) Use a completion to synchronize uvc_function_unbind() with the uvc_vdev_release() callback. This prevents Use-After-Free (UAF) by ensuring struct uvc_device is freed after all video device resources are released. Fixes: b81ac4395bbe ("usb: gadget: uvc: allow for application to cleanly shutdown") Cc: stable Suggested-by: Alan Stern Signed-off-by: Jimmy Hu Link: https://patch.msgid.link/20260320065427.1374555-1-hhhuuu@google.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman

usb: gadget: dummy_hcd: fix premature URB completion when ZLP follows partial transfer

2026-04-11T12:16:32+00:00

commit f50200dd44125e445a6164e88c217472fa79cdbc upstream. When a gadget request is only partially transferred in transfer() because the per-frame bandwidth budget is exhausted, the loop advances to the next queued request. If that next request is a zero-length packet (ZLP), len evaluates to zero and the code takes the unlikely(len == 0) path, which sets is_short = 1. This bypasses the bandwidth guard ("limit < ep->ep.maxpacket && limit < len") that lives in the else branch and would otherwise break out of the loop for non-zero requests. The is_short path then completes the URB before all data from the first request has been transferred. Reproducer (bulk IN, high speed): Device side (FunctionFS with Linux AIO): 1. Queue a 65024-byte write via io_submit (127 * 512, i.e. a multiple of the HS bulk max packet size). 2. Immediately queue a zero-length write (ZLP) via io_submit. Host side: 3. Submit a 65536-byte bulk IN URB. Expected: URB completes with actual_length = 65024. Actual: URB completes with actual_length = 53248, losing 11776 bytes that leak into subsequent URBs. At high speed the per-frame budget is 53248 bytes (512 * 13 * 8). The 65024-byte request exhausts this budget after 53248 bytes, leaving the request incomplete (req->req.actual < req->req.length). Neither the request nor the URB is finished, and rescan is 0, so the loop advances to the ZLP. For the ZLP, dev_len = 0, so len = min(12288, 0) = 0, taking the unlikely(len == 0) path and setting is_short = 1. The is_short handler then sets *status = 0, completing the URB with only 53248 of the expected 65024 bytes. Fix this by breaking out of the loop when the current request has remaining data (req->req.actual < req->req.length). The request resumes on the next timer tick, preserving correct data ordering. Signed-off-by: Sebastian Urban Cc: stable Reviewed-by: Alan Stern Link: https://patch.msgid.link/20260315151045.1155850-1-surban@surban.net Signed-off-by: Greg Kroah-Hartman

USB: dummy-hcd: Fix interrupt synchronization error

2026-04-11T12:16:32+00:00

commit 2ca9e46f8f1f5a297eb0ac83f79d35d5b3a02541 upstream. This fixes an error in synchronization in the dummy-hcd driver. The error has a somewhat involved history. The synchronization mechanism was introduced by commit 7dbd8f4cabd9 ("USB: dummy-hcd: Fix erroneous synchronization change"), which added an emulated "interrupts enabled" flag together with code emulating synchronize_irq() (it waits until all current handler callbacks have returned). But the emulated interrupt-disable occurred too late, after the driver containing the handler callback routines had been told that it was unbound and no more callbacks would occur. Commit 4a5d797a9f9c ("usb: gadget: dummy_hcd: fix gpf in gadget_setup") tried to fix this by moving the synchronize_irq() emulation code from dummy_stop() to dummy_pullup(), which runs before the unbind callback. There still were races, though, because the emulated interrupt-disable still occurred too late. It couldn't be moved to dummy_pullup(), because that routine can be called for reasons other than an impending unbind. Therefore commits 7dc0c55e9f30 ("USB: UDC core: Add udc_async_callbacks gadget op") and 04145a03db9d ("USB: UDC: Implement udc_async_callbacks in dummy-hcd") added an API allowing the UDC core to tell dummy-hcd exactly when emulated interrupts and their callbacks should be disabled. That brings us to the current state of things, which is still wrong because the emulated synchronize_irq() occurs before the emulated interrupt-disable! That's no good, beause it means that more emulated interrupts can occur after the synchronize_irq() emulation has run, leading to the possibility that a callback handler may be running when the gadget driver is unbound. To fix this, we have to move the synchronize_irq() emulation code yet again, to the dummy_udc_async_callbacks() routine, which takes care of enabling and disabling emulated interrupt requests. The synchronization will now run immediately after emulated interrupts are disabled, which is where it belongs. Signed-off-by: Alan Stern Fixes: 04145a03db9d ("USB: UDC: Implement udc_async_callbacks in dummy-hcd") Cc: stable Link: https://patch.msgid.link/c7bc93fe-4241-4d04-bd56-27c12ba35c97@rowland.harvard.edu Signed-off-by: Greg Kroah-Hartman

USB: dummy-hcd: Fix locking/synchronization error

2026-04-11T12:16:32+00:00

commit 616a63ff495df12863692ab3f9f7b84e3fa7a66d upstream. Syzbot testing was able to provoke an addressing exception and crash in the usb_gadget_udc_reset() routine in drivers/usb/gadgets/udc/core.c, resulting from the fact that the routine was called with a second ("driver") argument of NULL. The bad caller was set_link_state() in dummy_hcd.c, and the problem arose because of a race between a USB reset and driver unbind. These sorts of races were not supposed to be possible; commit 7dbd8f4cabd9 ("USB: dummy-hcd: Fix erroneous synchronization change"), along with a few followup commits, was written specifically to prevent them. As it turns out, there are (at least) two errors remaining in the code. Another patch will address the second error; this one is concerned with the first. The error responsible for the syzbot crash occurred because the stop_activity() routine will sometimes drop and then re-acquire the dum->lock spinlock. A call to stop_activity() occurs in set_link_state() when handling an emulated USB reset, after the test of dum->ints_enabled and before the increment of dum->callback_usage. This allowed another thread (doing a driver unbind) to sneak in and grab the spinlock, and then clear dum->ints_enabled and dum->driver. Normally this other thread would have to wait for dum->callback_usage to go down to 0 before it would clear dum->driver, but in this case it didn't have to wait since dum->callback_usage had not yet been incremented. The fix is to increment dum->callback_usage _before_ calling stop_activity() instead of after. Then the thread doing the unbind will not clear dum->driver until after the call to usb_gadget_udc_reset() safely returns and dum->callback_usage has been decremented again. Signed-off-by: Alan Stern Reported-by: syzbot+19bed92c97bee999e5db@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-usb/68fc7c9c.050a0220.346f24.023c.GAE@google.com/ Tested-by: syzbot+19bed92c97bee999e5db@syzkaller.appspotmail.com Fixes: 7dbd8f4cabd9 ("USB: dummy-hcd: Fix erroneous synchronization change") Cc: stable Link: https://patch.msgid.link/46135f42-fdbe-46b5-aac0-6ca70492af15@rowland.harvard.edu Signed-off-by: Greg Kroah-Hartman

cdc-acm: new quirk for EPSON HMD

2026-04-11T12:16:31+00:00

commit f97e96c303d689708f7f713d8f3afcc31f1237e9 upstream. This device has a union descriptor that is just garbage and needs a custom descriptor. In principle this could be done with a (conditionally activated) heuristic. That would match more devices without a need for defining a new quirk. However, this always carries the risk that the heuristics does the wrong thing and leads to more breakage. Defining the quirk and telling it exactly what to do is the safe and conservative approach. Signed-off-by: Oliver Neukum Cc: stable Link: https://patch.msgid.link/20260317084139.1461008-1-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman

usb: cdns3: gadget: fix state inconsistency on gadget init failure

2026-04-11T12:16:29+00:00

commit c32f8748d70c8fc77676ad92ed76cede17bf2c48 upstream. When cdns3_gadget_start() fails, the DRD hardware is left in gadget mode while software state remains INACTIVE, creating hardware/software state inconsistency. When switching to host mode via sysfs: echo host > /sys/class/usb_role/13180000.usb-role-switch/role The role state is not set to CDNS_ROLE_STATE_ACTIVE due to the error, so cdns_role_stop() skips cleanup because state is still INACTIVE. This violates the DRD controller design specification (Figure22), which requires returning to idle state before switching roles. This leads to a synchronous external abort in xhci_gen_setup() when setting up the host controller: [ 516.440698] configfs-gadget 13180000.usb: failed to start g1: -19 [ 516.442035] cdns-usb3 13180000.usb: Failed to add gadget [ 516.443278] cdns-usb3 13180000.usb: set role 2 has failed ... [ 1301.375722] xhci-hcd xhci-hcd.1.auto: xHCI Host Controller [ 1301.377716] Internal error: synchronous external abort: 96000010 [#1] PREEMPT SMP [ 1301.382485] pc : xhci_gen_setup+0xa4/0x408 [ 1301.393391] backtrace: ... xhci_gen_setup+0xa4/0x408 <-- CRASH xhci_plat_setup+0x44/0x58 usb_add_hcd+0x284/0x678 ... cdns_role_set+0x9c/0xbc <-- Role switch Fix by calling cdns_drd_gadget_off() in the error path to properly clean up the DRD gadget state. Fixes: 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver") Cc: stable Signed-off-by: Yongchao Wu Acked-by: Peter Chen Link: https://patch.msgid.link/20260401001000.5761-1-yongchao.wu@autochips.com Signed-off-by: Greg Kroah-Hartman

usb: cdns3: gadget: fix NULL pointer dereference in ep_queue

2026-04-11T12:16:29+00:00

commit 7f6f127b9bc34bed35f56faf7ecb1561d6b39000 upstream. When the gadget endpoint is disabled or not yet configured, the ep->desc pointer can be NULL. This leads to a NULL pointer dereference when __cdns3_gadget_ep_queue() is called, causing a kernel crash. Add a check to return -ESHUTDOWN if ep->desc is NULL, which is the standard return code for unconfigured endpoints. This prevents potential crashes when ep_queue is called on endpoints that are not ready. Fixes: 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver") Cc: stable Signed-off-by: Yongchao Wu Acked-by: Peter Chen Link: https://patch.msgid.link/20260331000407.613298-1-yongchao.wu@autochips.com Signed-off-by: Greg Kroah-Hartman