-
Sven Schnelle authored
The following sequence triggers a kernel stack overflow on s390x: mount -t tracefs tracefs /sys/kernel/tracing cd /sys/kernel/tracing echo function_graph > current_tracer [crash] This is because preempt_count_{add,sub} are in the list of traced functions, which can be demonstrated by: echo preempt_count_add >set_ftrace_filter echo function_graph > current_tracer [crash] The stack overflow happens because get_tod_clock_monotonic() gets called by ftrace but itself calls preempt_{disable,enable}(), which leads to a endless recursion. Fix this by using preempt_{disable,enable}_notrace(). Fixes: 01162068 ("s390/time: ensure get_clock_monotonic() returns monotonic values") Signed-off-by:
Sven Schnelle <svens@linux.ibm.com> Reviewed-by:
Vasily Gorbik <gor@linux.ibm.com> Signed-off-by:
Vasily Gorbik <gor@linux.ibm.com>
6feeee8e