mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-07 00:59:06 +00:00
usb: gadget: u_serial: Avoid spinlock recursion in __gs_console_push
[ Upstream commit e599046994
]
When serial console over USB is enabled, gs_console_connect
queues gs_console_work, where it acquires the spinlock and
queues the usb request, and this request goes to gadget layer.
Now consider a situation where gadget layer prints something
to dmesg, this will eventually call gs_console_write() which
requires cons->lock. And this causes spinlock recursion. Avoid
this by excluding usb_ep_queue from the spinlock.
spin_lock_irqsave //needs cons->lock
gs_console_write
.
.
_printk
__warn_printk
dev_warn/pr_err
.
.
[USB Gadget Layer]
.
.
usb_ep_queue
gs_console_work
__gs_console_push // acquires cons->lock
process_one_work
Signed-off-by: Prashanth K <quic_prashk@quicinc.com>
Link: https://lore.kernel.org/r/1683638872-6885-1-git-send-email-quic_prashk@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
parent
0d353e6cd3
commit
e20a23b342
1 changed files with 3 additions and 0 deletions
|
@ -916,8 +916,11 @@ static void __gs_console_push(struct gs_console *cons)
|
|||
}
|
||||
|
||||
req->length = size;
|
||||
|
||||
spin_unlock_irq(&cons->lock);
|
||||
if (usb_ep_queue(ep, req, GFP_ATOMIC))
|
||||
req->length = 0;
|
||||
spin_lock_irq(&cons->lock);
|
||||
}
|
||||
|
||||
static void gs_console_work(struct work_struct *work)
|
||||
|
|
Loading…
Reference in a new issue