On Mon, Mar 22, 2021 at 05:29:21PM -0400, Steven Rostedt wrote: > On Mon, 22 Mar 2021 22:18:17 +0100 > Arnd Bergmann <a...@kernel.org> wrote: > > > I think the code works correctly on all architectures we support because > > both 'int' and 'long' are returned in a register with any unused bits > > cleared. > > It is however undefined behavior in C because 'int' and 'long' are not > > compatible types, and the calling conventions don't have to allow this. > > Static calls (and so do tracepoints) currently rely on these kind of > "undefined behavior" in C. This isn't the only UB that it relies on.
Right, most of the kernel lives in UB. That's what we have -fwrapv -fno-strict-aliassing and lots of other bits for, to 'fix' the stupid C standard. This is one more of them, so just ignore the warning and make it go away: -Wno-cast-function-type seems to be the magic knob.
