Commit c6fd91f0 authored by bibo mao's avatar bibo mao Committed by Linus Torvalds
Browse files

[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: default avatarbibo 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: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent c9becf58

arch/i386/kernel/process.c

+0 −8
Original line number Diff line number Diff line
@@ -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();

arch/ia64/kernel/process.c

+0 −8
Original line number Diff line number Diff line
@@ -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 */

arch/powerpc/kernel/process.c

+0 −2
Original line number Diff line number Diff line
@@ -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();

}

arch/x86_64/kernel/process.c

+1 −8
Original line number Diff line number Diff line
@@ -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());

kernel/kprobes.c

+5 −5
Original line number Diff line number Diff line
@@ -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);

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