On Sunday 25 September 2016, Greg KH wrote:
Hi Arnd,
I'm getting the following build warnings on the 4.7-stable tree, any ideas what they are from:
In file included from ../kernel/trace/trace_irqsoff.c:15:0: ../kernel/trace/trace_irqsoff.c: In function ‘stop_critical_timings’: ../include/linux/ftrace.h:703:36: warning: calling ‘__builtin_return_address’ with a nonzero argument is unsafe [-Wframe-address] # define ftrace_return_address(n) __builtin_return_address(n) ^~~~~~~~~~~~~~~~~~~~~~~~~~~ ../include/linux/ftrace.h:710:38: note: in expansion of macro ‘ftrace_return_address’ #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1)) ^~~~~~~~~~~~~~~~~~~~~ ../kernel/trace/trace_irqsoff.c:433:38: note: in expansion of macro ‘CALLER_ADDR1’ stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1); ^~~~~~~~~~~~
It shows up in a few other places as well with this signature.
Same goes for the 4.4-stable tree
In mainline, this warning got disabled with 124a3d88fa20 ("Disable "frame-address" warning") and then later that change was partially reverted wtih 377ccbb48373 ("Makefile: Mute warning for __builtin_return_address(>0) for tracing only").
It's probably fine if you apply both to the stable kernel.
I think I never saw this particular warning in my ARM build tests.
Arnd