can: gs_usb: add missing lock to protect struct timecounter::cycle_last

The struct timecounter::cycle_last is a 64 bit variable, read by
timecounter_cyc2time(), and written by timecounter_read(). On 32 bit
architectures this is not atomic.

Add a spinlock to protect access to struct timecounter::cycle_last. In
the gs_usb_timestamp_read() callback the lock is dropped to execute a
sleeping synchronous USB transfer. This is safe, as the variable we
want to protect is accessed during this call.

Fixes: 45dfa45f52e6 ("can: gs_usb: add RX and TX hardware timestamp support")
Link: https://lore.kernel.org/all/[email protected]
Cc: John Whittington <[email protected]>
Tested-by: John Whittington <[email protected]>
Signed-off-by: Marc Kleine-Budde <[email protected]>

0 files changed, 0 insertions, 0 deletions