lockdep: fix incorrect percpu usage

The mainline kernel as of 2.6.34-rc5 is not affected by this problem because
commit 10fad5e46f6c7bdfb01b1a012380a38e3c6ab346 fixed it by refactoring.

lockdep fix incorrect percpu usage

Should use per_cpu_ptr() to obfuscate the per cpu pointers (RELOC_HIDE is needed
for per cpu pointers).

git blame points to commit:

lockdep.c: commit 8e18257d29238311e82085152741f0c3aa18b74d

But it's really just moving the code around. But it's enough to say that the
problems appeared before Jul 19 01:48:54 2007, which brings us back to 2.6.23.

It should be applied to stable 2.6.23.x to 2.6.33.x (or whichever of these
stable branches are still maintained).

(tested on 2.6.33.1 x86_64)

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Randy Dunlap <randy.dunlap@oracle.com>
CC: Eric Dumazet <dada1@cosmosbay.com>
CC: Rusty Russell <rusty@rustcorp.com.au>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
CC: Tejun Heo <tj@kernel.org>
CC: Ingo Molnar <mingo@elte.hu>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Greg Kroah-Hartman <gregkh@suse.de>
CC: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 3 insertions, 3 deletions

diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index c62ec14609b9..493a0efbb869 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -600,9 +600,9 @@ static int static_obj(void *obj)
          * percpu var?
          */
         for_each_possible_cpu(i) {
-                start = (unsigned long) &__per_cpu_start + per_cpu_offset(i);
-                end   = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM
-                                        + per_cpu_offset(i);
+                start = (unsigned long) per_cpu_ptr(&__per_cpu_start, i);
+                end   = (unsigned long) per_cpu_ptr(&__per_cpu_start, i)
+                                        + PERCPU_ENOUGH_ROOM;
 
                 if ((addr >= start) && (addr < end))
                         return 1;