| Date | Thu, 22 Apr 2010 12:10:21 -0700 | From | Greg KH <> | Subject | [170/197] lockdep: fix incorrect percpu usage |
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2.6.32-stable review patch. If anyone has any objections, please let us know.
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From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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>
--- kernel/lockdep.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -591,9 +591,9 @@ 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 + + PERCPU_ENOUGH_ROOM, i); if ((addr >= start) && (addr < end)) return 1;
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