[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>

diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
index 299e616740843f900d6bd1fdfce3d38a1373cb56..24b3e745478b9917940c34825d0c5102050ecaea 100644 (file)
--- a/arch/i386/kernel/process.c
+++ b/arch/i386/kernel/process.c
@@ -38,7 +38,6 @@
 #include <linux/kallsyms.h>
 #include <linux/ptrace.h>
 #include <linux/random.h>
-#include <linux/kprobes.h>
 
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
@@ -364,13 +363,6 @@ void exit_thread(void)
        struct task_struct *tsk = current;
        struct thread_struct *t = &tsk->thread;
 
-       /*
-        * Remove function-return probe instances associated with this task
-        * and put them back on the free list. Do not insert an exit probe for
-        * this function, it will be disabled by kprobe_flush_task if you do.
-        */
-       kprobe_flush_task(tsk);
-
        /* The process may have allocated an io port bitmap... nuke it. */
        if (unlikely(NULL != t->io_bitmap_ptr)) {
                int cpu = get_cpu();

diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index 309d59658e5ff9344bbd122c8d364fed8b8a1c09..355d57970ba31cf3368aa61e5c32c92b81a85029 100644 (file)
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -30,7 +30,6 @@
 #include <linux/efi.h>
 #include <linux/interrupt.h>
 #include <linux/delay.h>
-#include <linux/kprobes.h>
 
 #include <asm/cpu.h>
 #include <asm/delay.h>
@@ -738,13 +737,6 @@ void
 exit_thread (void)
 {
 
-       /*
-        * Remove function-return probe instances associated with this task
-        * and put them back on the free list. Do not insert an exit probe for
-        * this function, it will be disabled by kprobe_flush_task if you do.
-        */
-       kprobe_flush_task(current);
-
        ia64_drop_fpu(current);
 #ifdef CONFIG_PERFMON
        /* if needed, stop monitoring and flush state to perfmon context */

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 1770a066c2176f71afa3e736904d8744bf0e0b84..f698aa77127eb818e5568404c70b3728c0ca52f6 100644 (file)
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -35,7 +35,6 @@
 #include <linux/mqueue.h>
 #include <linux/hardirq.h>
 #include <linux/utsname.h>
-#include <linux/kprobes.h>
 
 #include <asm/pgtable.h>
 #include <asm/uaccess.h>
@@ -460,7 +459,6 @@ void show_regs(struct pt_regs * regs)
 
 void exit_thread(void)
 {
-       kprobe_flush_task(current);
        discard_lazy_cpu_state();
 }
 

diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c
index 81111835722d84cf7e561d4ffd21a75f33f0a708..0370720515f17568a2fdee8ae057aef3c12ba584 100644 (file)
--- a/arch/x86_64/kernel/process.c
+++ b/arch/x86_64/kernel/process.c
@@ -35,8 +35,8 @@
 #include <linux/ptrace.h>
 #include <linux/utsname.h>
 #include <linux/random.h>
-#include <linux/kprobes.h>
 #include <linux/notifier.h>
+#include <linux/kprobes.h>
 
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
@@ -353,13 +353,6 @@ void exit_thread(void)
        struct task_struct *me = current;
        struct thread_struct *t = &me->thread;
 
-       /*
-        * Remove function-return probe instances associated with this task
-        * and put them back on the free list. Do not insert an exit probe for
-        * this function, it will be disabled by kprobe_flush_task if you do.
-        */
-       kprobe_flush_task(me);
-
        if (me->thread.io_bitmap_ptr) { 
                struct tss_struct *tss = &per_cpu(init_tss, get_cpu());
 

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 1fb9f753ef6071c636701f6e0921f103e9f6aafc..1156eb0977d04db06b1daeb926d776e87c34a5b7 100644 (file)
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -323,10 +323,10 @@ struct hlist_head __kprobes *kretprobe_inst_table_head(struct task_struct *tsk)
 }
 
 /*
- * This function is called from exit_thread or flush_thread when task tk's
- * stack is being recycled so that we can recycle any function-return probe
- * instances associated with this task. These left over instances represent
- * probed functions that have been called but will never return.
+ * This function is called from finish_task_switch when task tk becomes dead,
+ * so that we can recycle any function-return probe instances associated
+ * with this task. These left over instances represent probed functions
+ * that have been called but will never return.
  */
 void __kprobes kprobe_flush_task(struct task_struct *tk)
 {
@@ -336,7 +336,7 @@ void __kprobes kprobe_flush_task(struct task_struct *tk)
        unsigned long flags = 0;
 
        spin_lock_irqsave(&kretprobe_lock, flags);
-        head = kretprobe_inst_table_head(current);
+        head = kretprobe_inst_table_head(tk);
         hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
                 if (ri->task == tk)
                         recycle_rp_inst(ri);

diff --git a/kernel/sched.c b/kernel/sched.c
index 7ffaabd64f893863bd485bd32b8f77e672cec9be..78acdefeccca268874f5b43457146043f99debcb 100644 (file)
--- 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);
+       }
 }
 
 /**