* Steven Rostedt [off-list ref] wrote:

This bit me in the butt.

I couldn't understand why my init app was segfaulting, with a kernel 
address, but a user RIP and RSP.  Well, the RIP I think was bogus, but 
the kernel address was always the start of "mcount".  Looking deeper, 
I printed out what was in the RSP (even though it was a user stack).  
It ended up showing me that the calling address was from the VDSO 
area. Looking even further, I found the offending culprit, which was 
vread_hpet.

Looking at the assembly dump, I saw the vread_hpet was calling mcount, 
but I could not see it in the code. Nor could I see it in hpet.i (-E 
option of compiling).

Well, I guess Ingo is a magician when it comes to compiler tricks, and 
has the mcount being called by "every!!" function, unless you add the 
"notrace" option.

This patch adds the notrace to vsyscall_fn, so that we don't have user 
land apps calling mcount and crashing!

doh - applied. Thanks!

	Ingo