kernel/git/stable/linux.git/drivers/usb/gadget, branch master

usb: gadget: uvc: fix dangling pointers in uvc_function_bind() and uvc_function_unbind()

2026-08-14T01:49:48+00:00

In uvc_function_bind() error path, we use usb_ep_free_request which uses uvc->control_req but does not set it to NULL afterwards. Thus, uvc->control_req is a dangling pointer causing a UAF. Also we do not set the uvc->control_buf pointer to NULL after freeing it, which is another dangling pointer. Fix it by setting uvc->control_req to NULL after we run usb_ep_free_request() and uvc->control_buf to NULL after kfree. Do the same for uvc_function_unbind(). Reported-by: syzbot+de553c19cb054f174a35@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=de553c19cb054f174a35 Fixes: 0f9df9393855 ("usb: gadget: uvc: fix error path in uvc_function_bind()") Fixes: 6d11ed76c45d ("usb: gadget: f_uvc: convert f_uvc to new function interface") Cc: stable@vger.kernel.org Signed-off-by: Jeffin Philip Link: https://patch.msgid.link/20260813174311.130823-1-jeffinphilip14@gmail.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: u_audio: Fix use-after-free on sound card disconnect

2026-08-14T01:49:31+00:00

g_audio_cleanup() invokes snd_card_free_when_closed() to initiate sound card teardown and immediately frees the underlying struct snd_uac_chip context. However, snd_card_free_when_closed() returns asynchronously while ALSA control elements (kctls) remain open in userspace. When userspace control applications access or close these open file descriptors, kctl callbacks attempt to dereference kctl->private_data pointing to &uac->c_prm or &uac->p_prm within the freed uac structure, resulting in a use-after-free (UAF) memory corruption. Fix this issue by deferring the destruction of struct snd_uac_chip until all references to the ALSA sound card are released. Register a custom card->private_free callback (u_audio_card_free) during g_audio_setup() that frees uac and its associated playback/capture request and ring buffers only when the sound card reference count drops to zero. Fixes: 6c67ed9ad9b8 ("usb: gadget: u_audio: don't let userspace block driver unbind") Cc: stable@vger.kernel.org Signed-off-by: Sonali Pradhan Link: https://patch.msgid.link/20260810071237.2207680-1-sonalipradhan@google.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_tcm: keep port count until LUN teardown completes

2026-08-14T01:49:21+00:00

tcm_usbg_drop_nexus() permits session removal once tpg_port_count reaches zero. However, usbg_port_unlink() currently decrements that count from the fabric_pre_unlink() callback, before core_dev_del_lun() waits for active se_lun references to drain. If removal of the last LUN races a nexus removal, the latter can observe a zero port count and call target_remove_session(). This frees sess_cmd_map while an in-flight struct usbg_cmd, including its work item, can still be accessed. Overlapping the last-LUN unlink with nexus removal reproduces this lifetime violation as a DEBUG_OBJECTS "free active" warning for usbg_cmd_work, followed by a target-core BUG/Oops. The generic target-core unlink path has no callback after core_dev_del_lun() completes. Add an optional fabric_post_unlink() callback and use it for the f_tcm port count. The count now remains nonzero until core_dev_del_lun() has finished draining active LUN references, preventing nexus removal from freeing the session during command completion. Fixes: c52661d60f63 ("usb-gadget: Initial merge of target module for UASP + BOT") Cc: stable@vger.kernel.org Signed-off-by: Shuangpeng Bai Link: https://patch.msgid.link/20260807060733.3186624-1-shuangpeng.kernel@gmail.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: snps_udc_plat: clean up PHY on probe deferral

2026-08-14T01:48:50+00:00

When the referenced extcon device has not registered yet, extcon_get_edev_by_phandle() returns -EPROBE_DEFER after the driver has initialized and powered on the PHY. The direct return bypasses the common cleanup path and leaves both operations unbalanced. Store the lookup error first and route deferred probing through exit_phy, while retaining the existing behavior of suppressing the error message for deferral. This issue was identified during our ongoing static-analysis research while reviewing kernel code. Fixes: 1b9f35adb0ff ("usb: gadget: udc: Add Synopsys UDC Platform driver") Cc: stable@vger.kernel.org Signed-off-by: Ijae Kim Signed-off-by: Myeonghun Pak Link: https://patch.msgid.link/20260804140510.37639-1-mhun512@gmail.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_tcm: fix deadlock in usbg_make_tpg()

2026-08-14T01:48:46+00:00

usbg_make_tpg() held dep_lock while calling configfs_depend_item_unlocked(), which acquires the configfs root inode lock when operating across subsystems. This creates a circular lock dependency with configfs_rmdir(): dep_lock -> configfs root inode lock -> su_mutex -> dep_lock In usbg_make_tpg(), dep_lock only serialized the read of opts->ready, which is a monotonic flag that transitions from false to true exactly once (in tcm_set_name()) and never reverts. Remove dep_lock from usbg_make_tpg() entirely and use READ_ONCE/WRITE_ONCE to access opts->ready locklessly instead. Reported-by: syzbot+c9f9d646b08f3b6032fe@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=c9f9d646b08f3b6032fe Fixes: 4bb8548df632 ("usb: gadget: f_tcm: add configfs support") Cc: stable@vger.kernel.org Signed-off-by: Yun Zhou Link: https://patch.msgid.link/20260731081151.285599-1-yun.zhou@windriver.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_fs: Fix Use-After-Free in AIO error path

2026-08-14T01:48:36+00:00

In ffs_epfile_write_iter() and ffs_epfile_read_iter(), when ffs_epfile_io() fails with an error other than -EIOCBQUEUED, the io_data structure (`p`) is freed. However, for AIO operations, the kiocb cancel function was already armed and kiocb->private was set to `p`. If a concurrent cancel operation (such as sys_io_cancel()) executes after ffs_epfile_io() fails but before the function frees `p`, a Use-After-Free can occur when the cancellation handler accesses the freed pointer. To securely fix this race condition, we must properly un-arm the cancellation. Invoking `kiocb->ki_complete()` does exactly this by acquiring `ctx->ctx_lock` and safely removing the kiocb from the active sequence. In doing so, it ensures that a parallel io_cancel can no longer discover the kiocb, effectively closing the race window. We then return -EIOCBQUEUED to notify the VFS layer that the kiocb has been consumed and it should avoid attempting to complete the request again or triggering subsequent completion handlers. Fixes: de2080d41b5d ("gadget/function/f_fs.c: close leaks") Cc: stable@vger.kernel.org Reported-by: Xingyu Jin Assisted-by: Antigravity:gemini-3.1-pro Signed-off-by: Neill Kapron Link: https://patch.msgid.link/20260724235100.106011-1-nkapron@google.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_fs: Prevent deadlock during ep0 read loop

2026-08-14T01:48:31+00:00

Currently, ffs_ep0_read() holds ffs->mutex when it prepares to go to sleep waiting for an event. When no setup events are pending, it calls wait_event_interruptible_exclusive_locked_irq() with the mutex still held. The wait macro deliberately drops the waitqueue spinlock before sleeping but does not drop the mutex. If a userspace daemon is polling ep0 via read() and the gadget is asynchronously torn down via configfs (e.g., echo "" > UDC), a deadlock can occur: 1. The configfs teardown calls functionfs_unbind(), which queues a FUNCTIONFS_UNBIND event. 2. The daemon wakes up, consumes the event, and drops the mutex. 3. However, if the daemon loops and immediately issues another read() before exiting, it reacquires ffs->mutex and again goes into an interruptible sleep. 4. Meanwhile, functionfs_unbind() continues execution and attempts to acquire ffs->mutex to tear down ep0req. 5. The kernel deadlocks because the configfs thread is stuck in an uninterruptible sleep waiting for the mutex, while the userspace daemon is in an interruptible sleep holding the mutex forever because no more events will arrive. To fix this, we drop both the waitqueue spinlock and ffs->mutex before going to sleep, and use wait_event_interruptible_exclusive() instead. Upon waking up, we jump back to the `retry` label to safely reacquire the mutex and re-evaluate the state machine. By not sleeping with ffs->mutex held, we natively decouple gadget teardowns (which require the mutex) from userspace polling. Fixes: ddf8abd25994 ("USB: f_fs: the FunctionFS driver") Cc: stable@vger.kernel.org Assisted-by: Antigravity:gemini-3.1-pro Signed-off-by: Neill Kapron Link: https://patch.msgid.link/20260724204117.4036015-1-nkapron@google.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: at91_udc: drain polled-VBUS timer/work before udc is freed

2026-08-14T01:48:27+00:00

In polled-VBUS mode (board.vbus_pin && board.vbus_polled), probe arms a self-restarting cycle: at91_vbus_timer() schedules vbus_timer_work, and at91_vbus_timer_work() calls at91_vbus_update() and re-arms the timer via mod_timer(). Both recover the same udc through container_of and dereference it on every iteration. Neither teardown path cancels this cycle. udc is devm-allocated, so it is freed after at91udc_remove() returns, and is likewise freed when probe fails and devres runs. A timer callback or work item that is pending or running at either point dereferences the freed udc. Add at91_udc_shutdown_vbus_timer() and call it from at91udc_remove() and from the usb_add_gadget_udc() failure path in probe; the remaining probe error paths fail before the timer is armed. timer_shutdown_sync() waits for a running callback and clears timer->function, which makes the work handler's mod_timer() a permanent no-op; cancel_work_sync() then drains any pending or running work whose re-arm attempt now does nothing. The timer must be shut down first, since cancelling the work alone would let the timer re-queue it. The guard mirrors probe: in IRQ mode the timer and work_struct are never initialized. This does not require a fault; a normal driver unbind can interleave with an already queued work item. This issue was found by an in-house static analysis tool. Fixes: 4037242c4f5f ("ARM: 6209/3: at91_udc: Add vbus polarity and polling mode") Cc: stable@vger.kernel.org Assisted-by: Codex:gpt-5.6 Signed-off-by: Fan Wu Link: https://patch.msgid.link/20260719042839.3167094-1-fanwu01@zju.edu.cn Signed-off-by: Greg Kroah-Hartman

usb: gadget: midi2: remove default configfs groups on teardown

2026-08-14T01:48:13+00:00

f_midi2_alloc_inst() creates default configfs child groups for the default endpoint and default block using configfs_add_default_group(), setting their internal refcount to 1. However, during function teardown in f_midi2_free_inst() or EP cleanup in f_midi2_ep_opts_release(), configfs_remove_default_groups() is never called, therefore never dropping the refcount and leaking struct f_midi2_ep_opts and f_midi2_block_opts. Add the missing configfs_remove_default_groups() in the afformentioned functions to free the structs properly. Fixes: 8b645922b223 ("usb: gadget: Add support for USB MIDI 2.0 function driver") Cc: stable@vger.kernel.org Reported-by: syzbot+eaa106d192c9daf37f95@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=eaa106d192c9daf37f95 Tested-by: syzbot+eaa106d192c9daf37f95@syzkaller.appspotmail.com Signed-off-by: Joshua Crofts Link: https://patch.msgid.link/20260730135811.1498-1-joshua.crofts1@gmail.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: uvc: Fix null pointer dereference in uvcg_video_init()

2026-08-14T01:48:08+00:00

In uvcg_video_init(), if kthread_run_worker() fails, the error logged uses uvcg_err(), however, the pointer it uses: video->uvc is not assigned at this point, triggering a null pointer dereference. Fix this by directly using uvc->func which is assigned already. Reported-by: syzbot+8dcac923582c28505fd7@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=8dcac923582c28505fd7 Fixes: f0bbfbd16b3b ("usb: gadget: uvc: rework to enqueue in pump worker from encoded queue") Cc: stable@vger.kernel.org Signed-off-by: Jeffin Philip Reviewed-by: Xu Yang Link: https://patch.msgid.link/20260804034338.7976-1-jeffinphilip14@gmail.com Signed-off-by: Greg Kroah-Hartman