Re: [PATCH] USB: serial: garmin_gps: queue the device reset

[sashiko-bot@kernel.org]

> From: Josef Bacik <josef@toxicpanda.com>
> 
> A private packet with the ID PRIV_PKTID_RESET_REQ that is written to the
> port makes garmin_write() call usb_kill_urb() and usb_reset_device().
> Both sleep, but the write operation of a tty driver must not: a line
> discipline may call it in atomic context, synchronous PPP for one under
> a spinlock with bottom halves disabled.  In addition usb_reset_device()
> has to be called with the device locked, which it is not here.
> 
> The reset also unbinds the driver inside the write: the disconnect hangs
> the tty up, ppp_sync_close() calls ppp_unregister_channel(), and that
> spins on pch->downl, which the writer holds.  The CPU is lost.
> 
> Unlink the URB and use usb_queue_reset_device(), which locks the device
> and resets it from a work item.
> 
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Cc: stable <stable@kernel.org>
> Signed-off-by: Josef Bacik <josef@toxicpanda.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Sashiko has reviewed this patch and found no issues.

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