From: Ananth N Mavinakayanahalli<ananth@xxxxxxxxxx>
For as long as kretprobes have existed, we've allocated NR_CPUS
instances of kretprobe_instance structures. With the default value of
CONFIG_NR_CPUS increasing on certain architectures, we are potentially
wasting kernel memory.
See http://sourceware.org/bugzilla/show_bug.cgi?id=10839#c3 for more
details.
Use a saner num_possible_cpus() instead of NR_CPUS for allocation.
Signed-off-by: Ananth N Mavinakayanahalli<ananth@xxxxxxxxxx>
---
kernel/kprobes.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
Index: linux-2.6.32-rc5/kernel/kprobes.c
===================================================================
--- linux-2.6.32-rc5.orig/kernel/kprobes.c
+++ linux-2.6.32-rc5/kernel/kprobes.c
@@ -1014,9 +1014,9 @@ int __kprobes register_kretprobe(struct
/* Pre-allocate memory for max kretprobe instances */
if (rp->maxactive<= 0) {
#ifdef CONFIG_PREEMPT
- rp->maxactive = max(10, 2 * NR_CPUS);
+ rp->maxactive = max(10, 2 * num_possible_cpus());
#else
- rp->maxactive = NR_CPUS;
+ rp->maxactive = num_possible_cpus();
#endif
}
spin_lock_init(&rp->lock);