On 20 Jul 2012, at 17:33, Konstantin Belousov wrote: > It is not related to dtrace at all, and indeed OFFSETOF_CURTHREAD is 0. > This is a bug in clang, we compile our kernel in freestanding environment.
The copies of the C spec that I have do not differentiate between freestanding and hosted environments for the validity of dereferencing a pointer value of 0. Doing so is undefined in all cases and any standards-compliant compiler is quite at liberty to eat your dog in such situations - it is explicitly not guaranteed to read the memory at linear address 0 (this is undefined for at least two reasons that I can think of from the C spec, and probably more). David_______________________________________________ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
