xen/spinlock: Fix UBSAN "load of address with insufficient space" in lock_prof_init()

xen/spinlock: Fix UBSAN "load of address with insufficient space" in lock_prof_init()

UBSAN complains:

  (XEN) ================================================================================
  (XEN) UBSAN: Undefined behaviour in common/spinlock.c:794:10
  (XEN) load of address ffff82d040ae24c8 with insufficient space
  (XEN) for an object of type 'struct lock_profile *'
  (XEN) ----[ Xen-4.20-unstable  x86_64  debug=y ubsan=y  Tainted:   C    ]----

This shows up with GCC-14, but not with GCC-12.  I have not bisected further.

Either way, the types for __lock_profile_{start,end} are incorrect.

They are an array of struct lock_profile pointers.  Correct the extern's
types, and adjust the loop to match.

No practical change.

Reported-by: Andreas Glashauser <ag@andreasglashauser.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
master commit: 542ac112fc68c66cfafc577e252404c21da4f75b
master date: 2024-10-14 16:14:26 +0100