On Fri, Jul 20, 2012 at 05:40:32PM +0200, Dimitry Andric wrote: > On 2012-07-20 16:49, Kim Culhan wrote: > > Seeing this for r:238655 > ... > > In file included from > > /usr/src/sys/modules/dtrace/dtrace/../../../sys/pcpu.h:44: > > ./machine/pcpu.h:226:13: error: indirection of non-volatile null > > pointer will be deleted, not trap > > [-Werror,-Wnull-dereference] > > : "m" (*(char *)OFFSETOF_CURTHREAD)); > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~ > > ./machine/pcpu.h:226:13: note: consider using __builtin_trap() or > > qualifying pointer with 'volatile' > > That's indeed a valid warning from clang, since OFFSETOF_CURTHREAD is > usually zero. It's probably due to recent work on dtrace. I'm not in > the neighborhood of a FreeBSD box right now to verify, but can you > please try to change the cast to "(volatile char *)"? That should fix > the warning.
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.
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