[ARM] Regression somewhere between 2.6.19 and 2.6.19-rc1

[Russell King <rmk+lkml@arm.linux.org.uk>]

I'm seeing utterly random behaviour from kernels on ARM SMP hardware
built after 2.6.19.  I won't bother trying to paste the kernel output;
sometimes the kernel locks solid (no IRQs, no output to say what's wrong).
Other times I get the first line of an oops repeating but with random
addresses.  Othertimes the oops doesn't complete.

2.6.19 runs fine.

So I just tried using git bisect to track down the problem.  First issue
that presky cmpxchg() causing a build error.  Ok, so I provide a version
to get around that.

Next problem:

fs/proc/proc_misc.c: In function `version_read_proc':
fs/proc/proc_misc.c:256: warning: implicit declaration of function `utsname'
fs/proc/proc_misc.c:256: error: invalid type argument of `->'
fs/proc/proc_misc.c:256: error: invalid type argument of `->'
make[3]: *** [fs/proc/proc_misc.o] Error 1
make[2]: *** [fs/proc] Error 2
make[1]: *** [fs] Error 2
make: *** [uImage] Error 2

It seems this breakage seems to have been introduced some 260-odd commits
prior to the point which git bisect wants me to test.

How do I tell git bisect "I can't test this, this is neither good nor bad,
please choose another to try" ?  Or is git bisect hopeless given the large
amount of unbuildable commits thanks to our weekly merges?

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of: