Commit 346fd59b authored by Srinivasa Ds's avatar Srinivasa Ds Committed by Linus Torvalds
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[PATCH] kprobes: list all active probes in the system 



This patch lists all active probes in the system by scanning through
kprobe_table[].  It takes care of aggregate handlers and prints the type of
the probe.  Letter "k" for kprobes, "j" for jprobes, "r" for kretprobes.
It also lists address of the instruction,its symbolic name(function name +
offset) and the module name.  One can access this file through
/sys/kernel/debug/kprobes/list.

Output looks like this
=====================
llm40:~/a # cat /sys/kernel/debug/kprobes/list
c0169ae3  r  sys_read+0x0
c0169ae3  k  sys_read+0x0
c01694c8  k  vfs_write+0x0
c0167d20  r  sys_open+0x0
f8e658a6  k  reiserfs_delete_inode+0x0  reiserfs
c0120f4a  k  do_fork+0x0
c0120f4a  j  do_fork+0x0
c0169b4a  r  sys_write+0x0
c0169b4a  k  sys_write+0x0
c0169622  r  vfs_read+0x0
=================================

[akpm@linux-foundation.org: cleanup]
[ananth@in.ibm.com: sparc build fix]
Signed-off-by: default avatarSrinivasa DS <srinivasa@in.ibm.com>
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 avatarAnanth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ffda9d30

kernel/kprobes.c

+111 −2
Original line number Diff line number Diff line
@@ -39,6 +39,8 @@ 
#include <linux/moduleloader.h>

#include <linux/kallsyms.h>

#include <linux/freezer.h>

#include <linux/seq_file.h>

#include <linux/debugfs.h>

#include <asm-generic/sections.h>

#include <asm/cacheflush.h>

#include <asm/errno.h>
@@ -778,6 +780,12 @@ int __kprobes register_kretprobe(struct kretprobe *rp) 
	return -ENOSYS;

}



static int __kprobes pre_handler_kretprobe(struct kprobe *p,

					   struct pt_regs *regs)

{

	return 0;

}



#endif /* ARCH_SUPPORTS_KRETPROBES */



void __kprobes unregister_kretprobe(struct kretprobe *rp)
@@ -815,7 +823,109 @@ static int __init init_kprobes(void) 
	return err;

}



__initcall(init_kprobes);

#ifdef CONFIG_DEBUG_FS

static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p,

               const char *sym, int offset,char *modname)

{

	char *kprobe_type;



	if (p->pre_handler == pre_handler_kretprobe)

		kprobe_type = "r";

	else if (p->pre_handler == setjmp_pre_handler)

		kprobe_type = "j";

	else

		kprobe_type = "k";

	if (sym)

		seq_printf(pi, "%p  %s  %s+0x%x  %s\n", p->addr, kprobe_type,

			sym, offset, (modname ? modname : " "));

	else

		seq_printf(pi, "%p  %s  %p\n", p->addr, kprobe_type, p->addr);

}



static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos)

{

	return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;

}



static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)

{

	(*pos)++;

	if (*pos >= KPROBE_TABLE_SIZE)

		return NULL;

	return pos;

}



static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v)

{

	/* Nothing to do */

}



static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v)

{

	struct hlist_head *head;

	struct hlist_node *node;

	struct kprobe *p, *kp;

	const char *sym = NULL;

	unsigned int i = *(loff_t *) v;

	unsigned long size, offset = 0;

	char *modname, namebuf[128];



	head = &kprobe_table[i];

	preempt_disable();

	hlist_for_each_entry_rcu(p, node, head, hlist) {

		sym = kallsyms_lookup((unsigned long)p->addr, &size,

					&offset, &modname, namebuf);

		if (p->pre_handler == aggr_pre_handler) {

			list_for_each_entry_rcu(kp, &p->list, list)

				report_probe(pi, kp, sym, offset, modname);

		} else

			report_probe(pi, p, sym, offset, modname);

	}

	preempt_enable();

	return 0;

}



static struct seq_operations kprobes_seq_ops = {

	.start = kprobe_seq_start,

	.next  = kprobe_seq_next,

	.stop  = kprobe_seq_stop,

	.show  = show_kprobe_addr

};



static int __kprobes kprobes_open(struct inode *inode, struct file *filp)

{

	return seq_open(filp, &kprobes_seq_ops);

}



static struct file_operations debugfs_kprobes_operations = {

	.open           = kprobes_open,

	.read           = seq_read,

	.llseek         = seq_lseek,

	.release        = seq_release,

};



static int __kprobes debugfs_kprobe_init(void)

{

	struct dentry *dir, *file;



	dir = debugfs_create_dir("kprobes", NULL);

	if (!dir)

		return -ENOMEM;



	file = debugfs_create_file("list", 0444, dir , 0 ,

				&debugfs_kprobes_operations);

	if (!file) {

		debugfs_remove(dir);

		return -ENOMEM;

	}



	return 0;

}



late_initcall(debugfs_kprobe_init);

#endif /* CONFIG_DEBUG_FS */



module_init(init_kprobes);



EXPORT_SYMBOL_GPL(register_kprobe);

EXPORT_SYMBOL_GPL(unregister_kprobe);
@@ -824,4 +934,3 @@ EXPORT_SYMBOL_GPL(unregister_jprobe); 
EXPORT_SYMBOL_GPL(jprobe_return);

EXPORT_SYMBOL_GPL(register_kretprobe);

EXPORT_SYMBOL_GPL(unregister_kretprobe);

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