[PATCH] kretprobe instance recycled by parent process

When kretprobe probes the schedule() function, if the probed process exits
then schedule() will never return, so some kretprobe instances will never
be recycled.

In this patch the parent process will recycle retprobe instances of the
probed function and there will be no memory leak of kretprobe instances.

Signed-off-by: bibo mao <bibo.mao@intel.com>
Cc: Masami Hiramatsu <hiramatu@sdl.hitachi.co.jp>
Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 8 insertions, 1 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 7ffaabd64f89..78acdefeccca 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -49,6 +49,7 @@
 #include <linux/syscalls.h>
 #include <linux/times.h>
 #include <linux/acct.h>
+#include <linux/kprobes.h>
 #include <asm/tlb.h>
 
 #include <asm/unistd.h>
@@ -1546,8 +1547,14 @@ static inline void finish_task_switch(runqueue_t *rq, task_t *prev)
         finish_lock_switch(rq, prev);
         if (mm)
                 mmdrop(mm);
-        if (unlikely(prev_task_flags & PF_DEAD))
+        if (unlikely(prev_task_flags & PF_DEAD)) {
+                /*
+                 * Remove function-return probe instances associated with this
+                 * task and put them back on the free list.
+                 */
+                kprobe_flush_task(prev);
                 put_task_struct(prev);
+        }
 }
 
 /**