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authorAnanth N Mavinakayanahalli <ananth@in.ibm.com>2009-10-30 19:23:10 +0530
committerIngo Molnar <mingo@elte.hu>2009-11-02 17:00:18 +0100
commit4dae560f97fa438f373b53e14b30149c9e44a600 (patch)
tree4408896d10c483e0f855636f8b9e208bd856d6fc /kernel/kprobes.c
parent5e9b397292ca0b9409dced33e3a22ec993377064 (diff)
kprobes: Sanitize struct kretprobe_instance allocations
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@in.ibm.com> Acked-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: fweisbec@gmail.com LKML-Reference: <20091030135310.GA22230@in.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/kprobes.c')
-rw-r--r--kernel/kprobes.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 5240d75f4c60..1494e85b35f2 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1014,9 +1014,9 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
/* 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);

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