On 12/04/2015 12:03 PM, Joe Perches wrote: > On Fri, 2015-12-04 at 11:47 -0500, Jason Baron wrote: >> When DYNAMIC_DEBUG is enabled we have this wrapper from >> include/linux/dynamic_debug.h: >> >> if (unlikely(descriptor.flags & _DPRINTK_FLAGS_PRINT)) >> <do debug stuff> >> >> So the compiler is not emitting the side-effects in this >> case. > > Huh? Do I misunderstand what you are writing? Yes, I wasn't terribly clear - I was trying to say that the 'side-effects', in this case the debug code and use-after-free, are hidden behind the branch. They aren't invoked unless we enable the debug statement. Thanks, -Jason > > You are testing a variable that is not generally set > so the call is not being performed in the general case, > but the compiler can not elide the code. > > If the variable was enabled via the control file, the > __dynamic_pr_debug would be performed with the > use-after-free. > -- To unsubscribe from this list: send the line "unsubscribe linux-sctp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
