6.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Peter Korsgaard peter@korsgaard.com
[ Upstream commit 937a8a3a8d46a3377b4195cd8f2aa656666ebc8b ]
Similar to how it is done in the write path.
Add a disabled flag to track the function state and use it to exit the read loops to ensure no readers get stuck when the function is disabled/unbound, protecting against corruption when the waitq and spinlocks are reinitialized in hidg_bind().
Signed-off-by: Peter Korsgaard peter@korsgaard.com Link: https://lore.kernel.org/r/20250318152207.330997-1-peter@korsgaard.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/usb/gadget/function/f_hid.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c index c7a05f842745b..d8bd2d82e9ec6 100644 --- a/drivers/usb/gadget/function/f_hid.c +++ b/drivers/usb/gadget/function/f_hid.c @@ -75,6 +75,7 @@ struct f_hidg { /* recv report */ spinlock_t read_spinlock; wait_queue_head_t read_queue; + bool disabled; /* recv report - interrupt out only (use_out_ep == 1) */ struct list_head completed_out_req; unsigned int qlen; @@ -329,7 +330,7 @@ static ssize_t f_hidg_intout_read(struct file *file, char __user *buffer,
spin_lock_irqsave(&hidg->read_spinlock, flags);
-#define READ_COND_INTOUT (!list_empty(&hidg->completed_out_req)) +#define READ_COND_INTOUT (!list_empty(&hidg->completed_out_req) || hidg->disabled)
/* wait for at least one buffer to complete */ while (!READ_COND_INTOUT) { @@ -343,6 +344,11 @@ static ssize_t f_hidg_intout_read(struct file *file, char __user *buffer, spin_lock_irqsave(&hidg->read_spinlock, flags); }
+ if (hidg->disabled) { + spin_unlock_irqrestore(&hidg->read_spinlock, flags); + return -ESHUTDOWN; + } + /* pick the first one */ list = list_first_entry(&hidg->completed_out_req, struct f_hidg_req_list, list); @@ -387,7 +393,7 @@ static ssize_t f_hidg_intout_read(struct file *file, char __user *buffer, return count; }
-#define READ_COND_SSREPORT (hidg->set_report_buf != NULL) +#define READ_COND_SSREPORT (hidg->set_report_buf != NULL || hidg->disabled)
static ssize_t f_hidg_ssreport_read(struct file *file, char __user *buffer, size_t count, loff_t *ptr) @@ -1012,6 +1018,11 @@ static void hidg_disable(struct usb_function *f) } spin_unlock_irqrestore(&hidg->get_report_spinlock, flags);
+ spin_lock_irqsave(&hidg->read_spinlock, flags); + hidg->disabled = true; + spin_unlock_irqrestore(&hidg->read_spinlock, flags); + wake_up(&hidg->read_queue); + spin_lock_irqsave(&hidg->write_spinlock, flags); if (!hidg->write_pending) { free_ep_req(hidg->in_ep, hidg->req); @@ -1097,6 +1108,10 @@ static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt) } }
+ spin_lock_irqsave(&hidg->read_spinlock, flags); + hidg->disabled = false; + spin_unlock_irqrestore(&hidg->read_spinlock, flags); + if (hidg->in_ep != NULL) { spin_lock_irqsave(&hidg->write_spinlock, flags); hidg->req = req_in;