[PATCH] kretprobe events missing on 2-core KVM guest

[wuqiang]

Default value of maxactive is set as num_possible_cpus() for nonpreemptable
systems. For a 2-core system, only 2 kretprobe instances would be allocated
in default, then these 2 instances for execve kretprobe are very likely to
be used up with a pipelined command.

This patch increases the minimum of maxactive to 10.

Signed-off-by: wuqiang <wuqiang.matt@xxxxxxxxxxxxx>
---
 kernel/kprobes.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 3220b0a2fb4a..b781dee3f552 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2211,7 +2211,7 @@ int register_kretprobe(struct kretprobe *rp)
 #ifdef CONFIG_PREEMPTION
 		rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus());
 #else
-		rp->maxactive = num_possible_cpus();
+		rp->maxactive = max_t(unsigned int, 10, num_possible_cpus());
 #endif
 	}
 #ifdef CONFIG_KRETPROBE_ON_RETHOOK
-- 
2.34.1