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* [PATCH] Kprobes /proc entry
@ 2005-01-10 16:25 Luca Falavigna
  2005-01-10 18:14 ` Greg KH
  0 siblings, 1 reply; 13+ messages in thread
From: Luca Falavigna @ 2005-01-10 16:25 UTC (permalink / raw)
  To: vamsi_krishna, prasanna; +Cc: suparna, linux-kernel

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

This simple patch adds a new file in /proc, listing every kprobe which
is currently registered in the kernel. This patch is checked against
kernel 2.6.10



- --- ./kernel/kprobes.c	2005-01-03 20:40:52.000000000 +0100
+++ ./kernel/kprobes.c	2005-01-10 15:19:17.000000000 +0100
@@ -32,6 +32,7 @@
 #include <linux/spinlock.h>
 #include <linux/hash.h>
 #include <linux/init.h>
+#include <linux/kallsyms.h>
 #include <linux/module.h>
 #include <asm/cacheflush.h>
 #include <asm/errno.h>
@@ -131,6 +132,70 @@
 	unregister_kprobe(&jp->kp);
 }

+void get_kprobes_info(struct kprobe *k, char *p)
+{
+	int len = 0;
+	char *module, namebuf[KSYM_NAME_LEN+1];
+	const char *hook, *func;
+	unsigned long off, size, handler, addr = (unsigned long)k->addr;
+
+	if(k->pre_handler) {
+		handler = (unsigned long)k->pre_handler;
+		func = kallsyms_lookup(addr, &size, &off, &module, namebuf);
+		len += sprintf(p + len, "PRE 0x%lx(%s+%#lx)\t",
+			       addr, func, off);
+		hook = kallsyms_lookup(handler, &size, &off, &module, namebuf);
+		len += sprintf(p + len, "0x%lx(%s)\t%s\n", handler, hook,
+			       strlen(module) ? module : "[built-in]");
+	}
+	if(k->post_handler) {
+		handler = (unsigned long)k->pre_handler;
+		func = kallsyms_lookup(addr, &size, &off, &module, namebuf);
+		hook = kallsyms_lookup(handler, &size, &off, &module, namebuf);
+		len += sprintf(p + len, "POST\t0x%lx(%s)\t0x%lx(%s)\t%s\n",
+			       handler, hook, addr, func,
+			       strlen(module) ? module : "[built-in]");
+	}
+	if(k->fault_handler) {
+		handler = (unsigned long)k->pre_handler;
+		func = kallsyms_lookup(addr, &size, &off, &module, namebuf);
+		hook = kallsyms_lookup(handler, &size, &off, &module, namebuf);
+		len += sprintf(p + len, "FAULT\t0x%lx(%s)\t0x%lx(%s)\t%s\n",
+			       handler, hook, addr, func,
+			       strlen(module) ? module : "[built-in]");
+	}
+	if(k->break_handler) {
+		handler = (unsigned long)k->pre_handler;
+		func = kallsyms_lookup(addr, &size, &off, &module, namebuf);
+		hook = kallsyms_lookup(handler, &size, &off, &module, namebuf);
+		len += sprintf(p + len, "BREAK\t0x%lx(%s)\t0x%lx(%s)\t%s\n",
+			       handler, hook, addr, func,
+			       strlen(module) ? module : "[built-in]");
+	}
+}
+
+int get_kprobes_list(char *page)
+{
+
+	int i, len = 0;
+	struct hlist_head *head;
+	struct hlist_node *node;
+	struct kprobe *k;
+
+	spin_lock(&kprobe_lock);
+	for(i = 0; i < KPROBE_TABLE_SIZE; i++) {
+		head = &kprobe_table[i];
+		hlist_for_each(node, head) {
+			if((k = hlist_entry(node, struct kprobe, hlist))) {
+				get_kprobes_info(k, page + len);
+				len = strlen(page);
+			}
+		}
+	}
+	spin_unlock(&kprobe_lock);
+	return len;
+}
+
 static int __init init_kprobes(void)
 {
 	int i, err = 0;
- --- ./fs/proc/proc_misc.c	2005-01-03 20:40:44.000000000 +0100
+++ ./fs/proc/proc_misc.c	2005-01-09 23:50:32.000000000 +0100
@@ -66,6 +66,7 @@
 extern int get_exec_domain_list(char *);
 extern int get_dma_list(char *);
 extern int get_locks_status (char *, char **, off_t, int);
+extern int get_kprobes_list(char *);

 static int proc_calc_metrics(char *page, char **start, off_t off,
 				 int count, int *eof, int len)
@@ -547,6 +548,15 @@
 	return proc_calc_metrics(page, start, off, count, eof, len);
 }

+#ifdef CONFIG_KPROBES
+static int kprobes_read_proc(char *page, char **start, off_t off,
+			     int count, int *eof, void *data)
+{
+	int len = get_kprobes_list(page);
+	return proc_calc_metrics(page, start, off, count, eof, len);
+}
+#endif
+
 #ifdef CONFIG_MAGIC_SYSRQ
 /*
  * writing 'C' to /proc/sysrq-trigger is like sysrq-C
@@ -601,6 +611,9 @@
 		{"cmdline",	cmdline_read_proc},
 		{"locks",	locks_read_proc},
 		{"execdomains",	execdomains_read_proc},
+#ifdef CONFIG_KPROBES
+		{"kprobes", kprobes_read_proc},
+#endif
 		{NULL,}
 	};
 	for (p = simple_ones; p->name; p++)

Signed-off-by: Luca Falavigna <dktrkranz@gmail.com>



Regards,

					Luca

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^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH] Kprobes /proc entry
  2005-01-10 16:25 [PATCH] Kprobes /proc entry Luca Falavigna
@ 2005-01-10 18:14 ` Greg KH
  2005-01-11 21:31   ` Nathan Lynch
  0 siblings, 1 reply; 13+ messages in thread
From: Greg KH @ 2005-01-10 18:14 UTC (permalink / raw)
  To: Luca Falavigna; +Cc: vamsi_krishna, prasanna, suparna, linux-kernel

On Mon, Jan 10, 2005 at 05:25:38PM +0100, Luca Falavigna wrote:
> This simple patch adds a new file in /proc, listing every kprobe which
> is currently registered in the kernel. This patch is checked against
> kernel 2.6.10

No, please do not add extra /proc files to the kernel.  This belongs in
/sys, as it has _nothing_ to do with processes.

thanks,

greg k-h

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH] Kprobes /proc entry
  2005-01-10 18:14 ` Greg KH
@ 2005-01-11 21:31   ` Nathan Lynch
  2005-01-11 21:34     ` Greg KH
  0 siblings, 1 reply; 13+ messages in thread
From: Nathan Lynch @ 2005-01-11 21:31 UTC (permalink / raw)
  To: Greg KH; +Cc: Luca Falavigna, vamsi_krishna, prasanna, suparna, lkml

On Mon, 2005-01-10 at 12:14, Greg KH wrote:
> On Mon, Jan 10, 2005 at 05:25:38PM +0100, Luca Falavigna wrote:
> > This simple patch adds a new file in /proc, listing every kprobe which
> > is currently registered in the kernel. This patch is checked against
> > kernel 2.6.10
> 
> No, please do not add extra /proc files to the kernel.  This belongs in
> /sys, as it has _nothing_ to do with processes.

Wouldn't this sort of thing be a good candidate for debugfs?  If you're
messing with kprobes, then aren't you by definition doing kernel
debugging? :)


Nathan



^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH] Kprobes /proc entry
  2005-01-11 21:31   ` Nathan Lynch
@ 2005-01-11 21:34     ` Greg KH
  2005-01-12  0:09       ` Luca Falavigna
  2005-01-13 23:20       ` Luca Falavigna
  0 siblings, 2 replies; 13+ messages in thread
From: Greg KH @ 2005-01-11 21:34 UTC (permalink / raw)
  To: Nathan Lynch; +Cc: Luca Falavigna, vamsi_krishna, prasanna, suparna, lkml

On Tue, Jan 11, 2005 at 03:31:17PM -0600, Nathan Lynch wrote:
> On Mon, 2005-01-10 at 12:14, Greg KH wrote:
> > On Mon, Jan 10, 2005 at 05:25:38PM +0100, Luca Falavigna wrote:
> > > This simple patch adds a new file in /proc, listing every kprobe which
> > > is currently registered in the kernel. This patch is checked against
> > > kernel 2.6.10
> > 
> > No, please do not add extra /proc files to the kernel.  This belongs in
> > /sys, as it has _nothing_ to do with processes.
> 
> Wouldn't this sort of thing be a good candidate for debugfs?  If you're
> messing with kprobes, then aren't you by definition doing kernel
> debugging? :)

That's an even better idea, I like it.

greg k-h

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH] Kprobes /proc entry
  2005-01-11 21:34     ` Greg KH
@ 2005-01-12  0:09       ` Luca Falavigna
  2005-01-12  6:35         ` Prasanna S Panchamukhi
  2005-01-13 23:20       ` Luca Falavigna
  1 sibling, 1 reply; 13+ messages in thread
From: Luca Falavigna @ 2005-01-12  0:09 UTC (permalink / raw)
  To: Greg KH, Nathan Lynch; +Cc: vamsi_krishna, prasanna, suparna, lkml

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Greg KH ha scritto:
> On Tue, Jan 11, 2005 at 03:31:17PM -0600, Nathan Lynch wrote:
> 
>>On Mon, 2005-01-10 at 12:14, Greg KH wrote:
>>
>>>On Mon, Jan 10, 2005 at 05:25:38PM +0100, Luca Falavigna wrote:
>>>
>>>>This simple patch adds a new file in /proc, listing every kprobe which
>>>>is currently registered in the kernel. This patch is checked against
>>>>kernel 2.6.10
>>>
>>>No, please do not add extra /proc files to the kernel.  This belongs in
>>>/sys, as it has _nothing_ to do with processes.
>>
>>Wouldn't this sort of thing be a good candidate for debugfs?  If you're
>>messing with kprobes, then aren't you by definition doing kernel
>>debugging? :)
> 
> 
> That's an even better idea, I like it.
> 
> greg k-h
> 

Good, I'll work on it ASAP.
Thank you for your suggestions!

					Luca
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^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH] Kprobes /proc entry
  2005-01-12  0:09       ` Luca Falavigna
@ 2005-01-12  6:35         ` Prasanna S Panchamukhi
  2005-01-12  9:49           ` Prasanna S Panchamukhi
  0 siblings, 1 reply; 13+ messages in thread
From: Prasanna S Panchamukhi @ 2005-01-12  6:35 UTC (permalink / raw)
  To: Luca Falavigna
  Cc: Greg KH, Nathan Lynch, vamsi_krishna, suparna, lkml, maneesh

Hi Luca,

Applied kernel probes can also be listed using SysRq key.
Below is the small patch that provides this feature.
Please let me know your comments.

Thanks
Prasanna
> 
> Greg KH ha scritto:
> > On Tue, Jan 11, 2005 at 03:31:17PM -0600, Nathan Lynch wrote:
> > 
> >>On Mon, 2005-01-10 at 12:14, Greg KH wrote:
> >>
> >>>On Mon, Jan 10, 2005 at 05:25:38PM +0100, Luca Falavigna wrote:
> >>>
> >>>>This simple patch adds a new file in /proc, listing every kprobe which
> >>>>is currently registered in the kernel. This patch is checked against
> >>>>kernel 2.6.10
> >>>
> >>>No, please do not add extra /proc files to the kernel.  This belongs in
> >>>/sys, as it has _nothing_ to do with processes.
> >>
> >>Wouldn't this sort of thing be a good candidate for debugfs?  If you're
> >>messing with kprobes, then aren't you by definition doing kernel
> >>debugging? :)
> > 
> > 
> > That's an even better idea, I like it.
> > 
> > greg k-h
> > 
> 
> Good, I'll work on it ASAP.
> Thank you for your suggestions!
> 
> 					Luca


---
Users like to list the kprobes inserted into the kernel.
This patch provides Sysrq-key to list all the kernel probes.
Usage Alt+SysRq+W to show the applied kprobes.
or $echo w > /proc/sysrq-trigger

Signed-of-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
---



---

 linux-2.6.10-prasanna/kernel/kprobes.c |   27 +++++++++++++++++++++++++++
 1 files changed, 27 insertions(+)

diff -puN kernel/kprobes.c~kprobes-sysrq-addn-feature kernel/kprobes.c
--- linux-2.6.10/kernel/kprobes.c~kprobes-sysrq-addn-feature	2005-01-12 11:54:08.000000000 +0530
+++ linux-2.6.10-prasanna/kernel/kprobes.c	2005-01-12 11:54:08.000000000 +0530
@@ -29,6 +29,8 @@
  *		exceptions notifier to be first on the priority list.
  */
 #include <linux/kprobes.h>
+#include <linux/sysrq.h>
+#include <linux/kallsyms.h>
 #include <linux/spinlock.h>
 #include <linux/hash.h>
 #include <linux/init.h>
@@ -131,10 +133,35 @@ void unregister_jprobe(struct jprobe *jp
 	unregister_kprobe(&jp->kp);
 }
 
+static void show_kprobes(int key, struct pt_regs *pt_regs, struct tty_struct *tty)
+{
+	int i;
+	struct hlist_node *node;
+
+	/* unsafe: kprobe_lock ought to be taken here */
+	for(i = 0; i < KPROBE_TABLE_SIZE; i++) {
+		if (!hlist_empty(&kprobe_table[i])) {
+			hlist_for_each(node, &kprobe_table[i]) {
+				struct kprobe *p = hlist_entry(node, struct kprobe, hlist);
+				printk("[<%p>] ", p->addr);
+				print_symbol("%s\t", (unsigned long)p->addr);
+				print_symbol("%s\n", (unsigned long)p->pre_handler);
+			}
+		}
+	}
+}
+
+static struct sysrq_key_op sysrq_show_kprobes = {
+	.handler        = show_kprobes,
+	.help_msg       = "shoWkprobes",
+	.action_msg     = "Show kprobes\n"
+};
+
 static int __init init_kprobes(void)
 {
 	int i, err = 0;
 
+	register_sysrq_key('w', &sysrq_show_kprobes);
 	/* FIXME allocate the probe table, currently defined statically */
 	/* initialize all list heads */
 	for (i = 0; i < KPROBE_TABLE_SIZE; i++)

_
-- 

Prasanna S Panchamukhi
Linux Technology Center
India Software Labs, IBM Bangalore
Ph: 91-80-25044636
<prasanna@in.ibm.com>

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH] Kprobes /proc entry
  2005-01-12  6:35         ` Prasanna S Panchamukhi
@ 2005-01-12  9:49           ` Prasanna S Panchamukhi
  0 siblings, 0 replies; 13+ messages in thread
From: Prasanna S Panchamukhi @ 2005-01-12  9:49 UTC (permalink / raw)
  To: Luca Falavigna
  Cc: Greg KH, Nathan Lynch, vamsi_krishna, suparna, lkml, maneesh

Hi Luca,

Below is the latest patch that provides sysrq key feature
to list the applied kernel probes.
Please let me know your comments.

Thanks
Prasanna

---
Users like to list the kprobes inserted into the kernel.
This patch provides Sysrq-key to list all the kernel probes.
Usage Alt+SysRq+W to show the applied kprobes.
or $echo w > /proc/sysrq-trigger

Signed-of-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
---



---

 linux-2.6.10-prasanna/kernel/kprobes.c |   25 +++++++++++++++++++++++++
 1 files changed, 25 insertions(+)

diff -puN kernel/kprobes.c~kprobes-sysrq-addn-feature kernel/kprobes.c
--- linux-2.6.10/kernel/kprobes.c~kprobes-sysrq-addn-feature	2005-01-12 12:29:49.000000000 +0530
+++ linux-2.6.10-prasanna/kernel/kprobes.c	2005-01-12 14:52:49.000000000 +0530
@@ -29,6 +29,8 @@
  *		exceptions notifier to be first on the priority list.
  */
 #include <linux/kprobes.h>
+#include <linux/sysrq.h>
+#include <linux/kallsyms.h>
 #include <linux/spinlock.h>
 #include <linux/hash.h>
 #include <linux/init.h>
@@ -131,10 +133,33 @@ void unregister_jprobe(struct jprobe *jp
 	unregister_kprobe(&jp->kp);
 }
 
+static void show_kprobes(int key, struct pt_regs *pt_regs, struct tty_struct *tty)
+{
+	int i;
+	struct hlist_node *node;
+
+	/* unsafe: kprobe_lock ought to be taken here */
+	for(i = 0; i < KPROBE_TABLE_SIZE; i++) {
+		struct kprobe *p;
+		hlist_for_each_entry(p, node, &kprobe_table[i], hlist) {
+				printk("[<%p>] ", p->addr);
+				print_symbol("%s\t", (unsigned long)p->addr);
+				print_symbol("%s\n", (unsigned long)p->pre_handler);
+		}
+	}
+}
+
+static struct sysrq_key_op sysrq_show_kprobes = {
+	.handler        = show_kprobes,
+	.help_msg       = "shoWkprobes",
+	.action_msg     = "Show kprobes\n"
+};
+
 static int __init init_kprobes(void)
 {
 	int i, err = 0;
 
+	register_sysrq_key('w', &sysrq_show_kprobes);
 	/* FIXME allocate the probe table, currently defined statically */
 	/* initialize all list heads */
 	for (i = 0; i < KPROBE_TABLE_SIZE; i++)

_
-- 

Prasanna S Panchamukhi
Linux Technology Center
India Software Labs, IBM Bangalore
Ph: 91-80-25044636
<prasanna@in.ibm.com>

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH] Kprobes /proc entry
  2005-01-11 21:34     ` Greg KH
  2005-01-12  0:09       ` Luca Falavigna
@ 2005-01-13 23:20       ` Luca Falavigna
  2005-01-13 23:34         ` Greg KH
  2005-01-14  0:22         ` Stephen Hemminger
  1 sibling, 2 replies; 13+ messages in thread
From: Luca Falavigna @ 2005-01-13 23:20 UTC (permalink / raw)
  To: vamsi_krishna, prasanna; +Cc: Greg KH, Nathan Lynch, suparna, lkml

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Voilà! Here is kprobes debug patch via debugfs.



- --- ./kernel/kprobes.c	2005-01-13 20:41:11.000000000 +0100
+++ ./kernel/kprobes.c	2005-01-13 20:39:27.000000000 +0100
@@ -33,6 +33,9 @@
 #include <linux/hash.h>
 #include <linux/init.h>
 #include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/debugfs.h>
+#include <linux/kallsyms.h>
 #include <asm/cacheflush.h>
 #include <asm/errno.h>
 #include <asm/kdebug.h>
@@ -131,6 +134,96 @@
 	unregister_kprobe(&jp->kp);
 }

+#ifdef CONFIG_DEBUG_FS
+int kprobes_open(struct inode *inode, struct file *file)
+{
+	try_module_get(THIS_MODULE);
+	return 0;
+}
+
+int kprobes_release(struct inode *inode, struct file *file)
+{
+	module_put(THIS_MODULE);
+	return 0;
+}
+
+void kprobes_list_info(struct kprobe *k, char *p)
+{
+	ssize_t len = 0;
+	char *module, namebuf[KSYM_NAME_LEN+1];
+	const char *hook, *func;
+	unsigned long off, size, handler, addr = (unsigned long)k->addr;
+
+	if(k->pre_handler) {
+		handler = (unsigned long)k->pre_handler;
+		func = kallsyms_lookup(addr, &size, &off, &module, namebuf);
+		len += sprintf(p + len, "PRE\t0x%lx(%s+%#lx)\t",
+			       addr, func, off);
+		hook = kallsyms_lookup(handler, &size, &off, &module, namebuf);
+		len += sprintf(p + len, "0x%lx(%s)\t%s\n", handler, hook,
+			       strlen(module) ? module : "[built-in]");
+	}
+	if(k->post_handler) {
+		handler = (unsigned long)k->post_handler;
+		func = kallsyms_lookup(addr, &size, &off, &module, namebuf);
+		len += sprintf(p + len, "POST\t0x%lx(%s+%#lx)\t",
+			       addr, func, off);
+		hook = kallsyms_lookup(handler, &size, &off, &module, namebuf);
+		len += sprintf(p + len, "0x%lx(%s)\t%s\n", handler, hook,
+			       strlen(module) ? module : "[built-in]");
+	}
+	if(k->fault_handler) {
+		handler = (unsigned long)k->fault_handler;
+		func = kallsyms_lookup(addr, &size, &off, &module, namebuf);
+		len += sprintf(p + len, "FAULT\t0x%lx(%s+%#lx)\t",
+			       addr, func, off);
+		hook = kallsyms_lookup(handler, &size, &off, &module, namebuf);
+		len += sprintf(p + len, "0x%lx(%s)\t%s\n", handler, hook,
+			       strlen(module) ? module : "[built-in]");
+	}
+	if(k->break_handler) {
+		handler = (unsigned long)k->break_handler;
+		func = kallsyms_lookup(addr, &size, &off, &module, namebuf);
+		len += sprintf(p + len, "BREAK\t0x%lx(%s+%#lx)\t",
+			       addr, func, off);
+		hook = kallsyms_lookup(handler, &size, &off, &module, namebuf);
+		len += sprintf(p + len, "0x%lx(%s)\t%s\n", handler, hook,
+			       strlen(module) ? module : "[built-in]");
+	}
+}
+
+ssize_t kprobes_read(struct file *file, char __user *buf,
+			 size_t size, loff_t *off)
+{
+	int i;
+	char *data = "";
+	ssize_t len = 0;
+	struct hlist_head *head;
+	struct hlist_node *node;
+	struct kprobe *k;
+	
+	spin_lock(&kprobe_lock);
+	for(i = 0; i < KPROBE_TABLE_SIZE; i++) {
+		head = &kprobe_table[i];
+		hlist_for_each(node, head) {
+			if((k = hlist_entry(node, struct kprobe, hlist))) {
+				kprobes_list_info(k, data + len);
+				len = strlen(data);
+			}
+		}
+	}
+	spin_unlock(&kprobe_lock);
+	return simple_read_from_buffer(buf, size, off, data, len);
+}
+
+struct dentry *kprobes_dir, *kprobes_list;
+struct file_operations kprobes_fops = {
+	.open = kprobes_open,
+	.read = kprobes_read,
+	.release = kprobes_release
+	};
+#endif
+
 static int __init init_kprobes(void)
 {
 	int i, err = 0;
@@ -140,6 +233,16 @@
 	for (i = 0; i < KPROBE_TABLE_SIZE; i++)
 		INIT_HLIST_HEAD(&kprobe_table[i]);

+#ifdef CONFIG_DEBUG_FS
+	if(!(kprobes_dir = debugfs_create_dir("kprobes", NULL)))
+		return -ENODEV;
+	if(!(kprobes_list = debugfs_create_file("list", S_IRUGO, kprobes_dir,
+					  	NULL, &kprobes_fops))) {
+		debugfs_remove(kprobes_dir);
+		return -ENODEV;
+	}
+#endif
+
 	err = register_die_notifier(&kprobe_exceptions_nb);
 	return err;

Signed-off-by: Luca Falavigna <dktrkranz@gmail.com>



Regards,

					Luca

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^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH] Kprobes /proc entry
  2005-01-13 23:20       ` Luca Falavigna
@ 2005-01-13 23:34         ` Greg KH
  2005-01-17 16:58           ` Luca Falavigna
  2005-01-14  0:22         ` Stephen Hemminger
  1 sibling, 1 reply; 13+ messages in thread
From: Greg KH @ 2005-01-13 23:34 UTC (permalink / raw)
  To: Luca Falavigna; +Cc: vamsi_krishna, prasanna, Nathan Lynch, suparna, lkml

On Fri, Jan 14, 2005 at 12:20:20AM +0100, Luca Falavigna wrote:
> 
> +#ifdef CONFIG_DEBUG_FS

This ifdef should not be needed.

> +int kprobes_open(struct inode *inode, struct file *file)

Shouldn't these calls be static?

> +{
> +	try_module_get(THIS_MODULE);

Check the return value of this call?

>  static int __init init_kprobes(void)
>  {
>  	int i, err = 0;
> @@ -140,6 +233,16 @@
>  	for (i = 0; i < KPROBE_TABLE_SIZE; i++)
>  		INIT_HLIST_HEAD(&kprobe_table[i]);
> 
> +#ifdef CONFIG_DEBUG_FS

ifdef not needed.

> +	if(!(kprobes_dir = debugfs_create_dir("kprobes", NULL)))
> +		return -ENODEV;
> +	if(!(kprobes_list = debugfs_create_file("list", S_IRUGO, kprobes_dir,
> +					  	NULL, &kprobes_fops))) {
> +		debugfs_remove(kprobes_dir);
> +		return -ENODEV;
> +	}

You never delete this file or directory on module unload, do you?

thanks,

greg k-h

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH] Kprobes /proc entry
  2005-01-13 23:20       ` Luca Falavigna
  2005-01-13 23:34         ` Greg KH
@ 2005-01-14  0:22         ` Stephen Hemminger
  1 sibling, 0 replies; 13+ messages in thread
From: Stephen Hemminger @ 2005-01-14  0:22 UTC (permalink / raw)
  To: linux-kernel

The module ref counting should be done by the VFS layer
not the interface. See below:

> - --- ./kernel/kprobes.c	2005-01-13 20:41:11.000000000 +0100
> +++ ./kernel/kprobes.c	2005-01-13 20:39:27.000000000 +0100
> @@ -33,6 +33,9 @@
>  #include <linux/hash.h>
>  #include <linux/init.h>
>  #include <linux/module.h>
> +#include <linux/fs.h>
> +#include <linux/debugfs.h>
> +#include <linux/kallsyms.h>
>  #include <asm/cacheflush.h>
>  #include <asm/errno.h>
>  #include <asm/kdebug.h>
> @@ -131,6 +134,96 @@
>  	unregister_kprobe(&jp->kp);
>  }
> 
> +#ifdef CONFIG_DEBUG_FS
> +int kprobes_open(struct inode *inode, struct file *file)
> +{
> +	try_module_get(THIS_MODULE);
not needed (see below).
> +	return 0;
> +}
> +
> +int kprobes_release(struct inode *inode, struct file *file)
> +{
> +	module_put(THIS_MODULE);
ditto

> +	return 0;
> +}

> +
> +struct dentry *kprobes_dir, *kprobes_list;
> +struct file_operations kprobes_fops = {
> +	.open = kprobes_open,
> +	.read = kprobes_read,
> +	.release = kprobes_release
Add:
	.owner = THIS_MODULE,


^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH] Kprobes /proc entry
  2005-01-13 23:34         ` Greg KH
@ 2005-01-17 16:58           ` Luca Falavigna
  2005-01-18  6:44             ` Greg KH
  0 siblings, 1 reply; 13+ messages in thread
From: Luca Falavigna @ 2005-01-17 16:58 UTC (permalink / raw)
  To: Greg KH, vamsi_krishna, prasanna
  Cc: Nathan Lynch, suparna, lkml, Stephen Hemminger

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Here is a modified version of kprobes patch fixing some issues reported by Greg.

Greg KH ha scritto:
>>+{
>>+	try_module_get(THIS_MODULE);
> 
> 
> Check the return value of this call?
I removed try_module_get() and module_put() because of Stephen Hemminger's mail:
"The module ref counting should be done by the VFS layer not the interface."
Thank you for this hint :)

>>+	if(!(kprobes_dir = debugfs_create_dir("kprobes", NULL)))
>>+		return -ENODEV;
>>+	if(!(kprobes_list = debugfs_create_file("list", S_IRUGO, kprobes_dir,
>>+					  	NULL, &kprobes_fops))) {
>>+		debugfs_remove(kprobes_dir);
>>+		return -ENODEV;
>>+	}
> 
> 
> You never delete this file or directory on module unload, do you?
kprobes are a built-in feature, I think there's no way to handle this.
Please, tell me if I am wrong.



- --- ./kernel/kprobes.c	2005-01-17 17:56:11.000000000 +0100
+++ ./kernel/kprobes.c	2005-01-17 17:46:04.000000000 +0100
@@ -33,6 +33,9 @@
 #include <linux/hash.h>
 #include <linux/init.h>
 #include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/debugfs.h>
+#include <linux/kallsyms.h>
 #include <asm/cacheflush.h>
 #include <asm/errno.h>
 #include <asm/kdebug.h>
@@ -131,6 +134,88 @@
 	unregister_kprobe(&jp->kp);
 }

+static int kprobes_open(struct inode *inode, struct file *file)
+{
+	return 0;
+}
+
+static int kprobes_release(struct inode *inode, struct file *file)
+{
+	return 0;
+}
+
+void kprobes_list_info(struct kprobe *k, char *buf)
+{
+	char *module, namebuf[KSYM_NAME_LEN+1];
+	const char *hook, *func;
+	unsigned long off, size, handler, addr = (unsigned long)k->addr;
+
+	if(k->pre_handler) {
+		handler = (unsigned long)k->pre_handler;
+		func = kallsyms_lookup(addr, &size, &off, &module, namebuf);
+		buf += sprintf(buf, "PRE\t0x%lx(%s+%#lx)\t", addr, func, off);
+		hook = kallsyms_lookup(handler, &size, &off, &module, namebuf);
+		buf += sprintf(buf, "0x%lx(%s)\t%s\n", handler, hook,
+			       strlen(module) ? module : "[built-in]");
+	}
+	if(k->post_handler) {
+		handler = (unsigned long)k->post_handler;
+		func = kallsyms_lookup(addr, &size, &off, &module, namebuf);
+		buf += sprintf(buf, "POST\t0x%lx(%s+%#lx)\t", addr, func, off);
+		hook = kallsyms_lookup(handler, &size, &off, &module, namebuf);
+		buf += sprintf(buf, "0x%lx(%s)\t%s\n", handler, hook,
+			       strlen(module) ? module : "[built-in]");
+	}
+	if(k->fault_handler) {
+		handler = (unsigned long)k->fault_handler;
+		func = kallsyms_lookup(addr, &size, &off, &module, namebuf);
+		buf += sprintf(buf, "FAULT\t0x%lx(%s+%#lx)\t",
+			       addr, func, off);
+		hook = kallsyms_lookup(handler, &size, &off, &module, namebuf);
+		buf += sprintf(buf, "0x%lx(%s)\t%s\n", handler, hook,
+			       strlen(module) ? module : "[built-in]");
+	}
+	if(k->break_handler) {
+		handler = (unsigned long)k->break_handler;
+		func = kallsyms_lookup(addr, &size, &off, &module, namebuf);
+		buf += sprintf(buf, "BREAK\t0x%lx(%s+%#lx)\t",
+			       addr, func, off);
+		hook = kallsyms_lookup(handler, &size, &off, &module, namebuf);
+		buf += sprintf(buf, "0x%lx(%s)\t%s\n", handler, hook,
+			       strlen(module) ? module : "[built-in]");
+	}
+}
+
+static ssize_t kprobes_read(struct file *file, char __user *buf,
+			 size_t size, loff_t *off)
+{
+	int i;
+	char *data = "";
+	ssize_t len = 0;
+	struct hlist_node *node;
+	struct kprobe *k;
+	
+	spin_lock(&kprobe_lock);
+	for(i = 0; i < KPROBE_TABLE_SIZE; i++) {
+		hlist_for_each_entry(k, node, &kprobe_table[i], hlist) {
+			if(k) {
+				kprobes_list_info(k, data + len);
+				len += strlen(data);
+			}
+		}
+	}
+	spin_unlock(&kprobe_lock);
+	return simple_read_from_buffer(buf, size, off, data, len);
+}
+
+struct dentry *kprobes_dir, *kprobes_list;
+struct file_operations kprobes_fops = {
+	.open = kprobes_open,
+	.read = kprobes_read,
+	.release = kprobes_release,
+	.owner = THIS_MODULE
+};
+
 static int __init init_kprobes(void)
 {
 	int i, err = 0;
@@ -140,6 +225,20 @@
 	for (i = 0; i < KPROBE_TABLE_SIZE; i++)
 		INIT_HLIST_HEAD(&kprobe_table[i]);

+	kprobes_dir = debugfs_create_dir("kprobes", NULL);
+	if(!kprobes_dir) {
+		printk("kprobes: could not create debugfs entry\n");
+		goto finish;
+	}
+	kprobes_list = debugfs_create_file("list", S_IRUGO, kprobes_dir,
+					  	NULL, &kprobes_fops);
+	if(!kprobes_list) {		
+		printk("kprobes: could not create debugfs entry\n");
+		debugfs_remove(kprobes_dir);
+		goto finish;
+	}
+
+finish:
 	err = register_die_notifier(&kprobe_exceptions_nb);
 	return err;
 }

Signed-off-by: Luca Falavigna <dktrkranz@gmail.com>



Regards,

					Luca
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^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH] Kprobes /proc entry
  2005-01-17 16:58           ` Luca Falavigna
@ 2005-01-18  6:44             ` Greg KH
  2005-01-20 14:13               ` Luca Falavigna
  0 siblings, 1 reply; 13+ messages in thread
From: Greg KH @ 2005-01-18  6:44 UTC (permalink / raw)
  To: Luca Falavigna
  Cc: vamsi_krishna, prasanna, Nathan Lynch, suparna, lkml, Stephen Hemminger

On Mon, Jan 17, 2005 at 05:58:00PM +0100, Luca Falavigna wrote:
> +static ssize_t kprobes_read(struct file *file, char __user *buf,
> +			 size_t size, loff_t *off)
> +{
> +	int i;
> +	char *data = "";
> +	ssize_t len = 0;
> +	struct hlist_node *node;
> +	struct kprobe *k;
> +	
> +	spin_lock(&kprobe_lock);
> +	for(i = 0; i < KPROBE_TABLE_SIZE; i++) {
> +		hlist_for_each_entry(k, node, &kprobe_table[i], hlist) {
> +			if(k) {
> +				kprobes_list_info(k, data + len);
> +				len += strlen(data);
> +			}
> +		}
> +	}
> +	spin_unlock(&kprobe_lock);
> +	return simple_read_from_buffer(buf, size, off, data, len);

Am I missing where you allocate the space for the data to be put into?

Also, why not use the seqfile interface for this, to prevent overflowing
the read buffer?

thanks,

greg k-h

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH] Kprobes /proc entry
  2005-01-18  6:44             ` Greg KH
@ 2005-01-20 14:13               ` Luca Falavigna
  0 siblings, 0 replies; 13+ messages in thread
From: Luca Falavigna @ 2005-01-20 14:13 UTC (permalink / raw)
  To: Greg KH, vamsi_krishna, prasanna
  Cc: Nathan Lynch, suparna, lkml, Stephen Hemminger

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Greg KH ha scritto:
> Also, why not use the seqfile interface for this, to prevent overflowing
> the read buffer?
Great idea!

> Am I missing where you allocate the space for the data to be put into?
seq_read does the job now. It manages to allocate PAGE_SIZE bytes.
Assuming function, hook and module names occupy KSYM_NAME_LEN bytes each,
maximum length will be 424 bytes for each kprobe. I don't think it would be
useful to allocate more memory than PAGE_SIZE. Please, let me know your opinion.



- --- ./kernel/kprobes.c	2005-01-19 11:03:03.000000000 +0100
+++ ./kernel/kprobes.c	2005-01-20 15:02:47.000000000 +0100
@@ -33,6 +33,10 @@
 #include <linux/hash.h>
 #include <linux/init.h>
 #include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/debugfs.h>
+#include <linux/kallsyms.h>
+#include <linux/seq_file.h>
 #include <asm/cacheflush.h>
 #include <asm/errno.h>
 #include <asm/kdebug.h>
@@ -45,6 +49,13 @@
 unsigned int kprobe_cpu = NR_CPUS;
 static DEFINE_SPINLOCK(kprobe_lock);

+static char *ktype[] = {
+	"PRE",
+	"POST",
+	"FAULT",
+	"BREAK",
+};
+
 /* Locks kprobe: irqs must be disabled */
 void lock_kprobes(void)
 {
@@ -131,15 +142,92 @@
 	unregister_kprobe(&jp->kp);
 }

+static void kprobes_print(struct seq_file *seq, unsigned long addr,
+			  unsigned long handler, int type)
+{
+	char *module, namebuf[KSYM_NAME_LEN+1];
+	const char *hook, *func;
+	unsigned long off, size;
+
+	func = kallsyms_lookup(addr, &size, &off, &module, namebuf);
+	seq_printf(seq, "%s\t0x%lx(%s+%#lx)\t", ktype[type], addr, func, off);
+	hook = kallsyms_lookup(handler, &size, &off, &module, namebuf);
+	seq_printf(seq, "0x%lx(%s)\t%s\n", handler, hook,
+		   strlen(module) ? module : "[built-in]");
+}
+
+static int kprobes_show(struct seq_file *seq, void *unused)
+{
+	int i;
+	struct kprobe *k;
+	struct hlist_node *node;
+	unsigned long addr, handler;
+		
+	spin_lock(&kprobe_lock);
+	for(i = 0; i < KPROBE_TABLE_SIZE; i++) {
+		hlist_for_each_entry(k, node, &kprobe_table[i], hlist) {
+			if(!k)
+				continue;
+			addr = (unsigned long)k->addr;
+			if(k->pre_handler) {
+				handler = (unsigned long)k->pre_handler;
+				kprobes_print(seq, addr, handler, PRE);
+			}
+			if(k->post_handler) {
+				handler = (unsigned long)k->post_handler;
+				kprobes_print(seq, addr, handler, POST);
+			}
+			if(k->fault_handler) {
+				handler = (unsigned long)k->fault_handler;
+				kprobes_print(seq, addr, handler, FAULT);
+			}
+			if(k->break_handler) {
+				handler = (unsigned long)k->break_handler;
+				kprobes_print(seq, addr, handler, BREAK);
+			}
+		}
+	}
+	spin_unlock(&kprobe_lock);
+	return 0;
+}
+
+static int kprobes_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, kprobes_show, NULL);
+}
+
+static struct file_operations kprobes_fops = {
+	.open = kprobes_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+	.owner = THIS_MODULE
+};
+
 static int __init init_kprobes(void)
 {
 	int i, err = 0;
+	struct dentry *kprobes_dir, *kprobes_list;

 	/* FIXME allocate the probe table, currently defined statically */
 	/* initialize all list heads */
 	for (i = 0; i < KPROBE_TABLE_SIZE; i++)
 		INIT_HLIST_HEAD(&kprobe_table[i]);

+	kprobes_dir = debugfs_create_dir("kprobes", NULL);
+	if(!kprobes_dir) {
+		printk("kprobes: could not create debugfs entry\n");
+		goto finish;
+	}
+	kprobes_list = debugfs_create_file("list", S_IRUGO, kprobes_dir,
+					   NULL, &kprobes_fops);
+	if(!kprobes_list) {		
+		printk("kprobes: could not create debugfs entry\n");
+		debugfs_remove(kprobes_dir);
+		goto finish;
+	}
+
+finish:
 	err = register_die_notifier(&kprobe_exceptions_nb);
 	return err;
 }
- --- ./include/linux/kprobes.h	2005-01-03 20:40:51.000000000 +0100
+++ ./include/linux/kprobes.h	2005-01-20 13:59:27.000000000 +0100
@@ -82,6 +82,13 @@
 	kprobe_opcode_t *entry;	/* probe handling code to jump to */
 };

+enum kprobe_type {
+	PRE=0,
+	POST,
+	FAULT,
+	BREAK,
+};
+
 #ifdef CONFIG_KPROBES
 /* Locks kprobe: irq must be disabled */
 void lock_kprobes(void);

Signed-off-by: Luca Falavigna <dktrkranz@gmail.com>



Regards,

					Luca
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^ permalink raw reply	[flat|nested] 13+ messages in thread

end of thread, other threads:[~2005-01-20 17:39 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2005-01-10 16:25 [PATCH] Kprobes /proc entry Luca Falavigna
2005-01-10 18:14 ` Greg KH
2005-01-11 21:31   ` Nathan Lynch
2005-01-11 21:34     ` Greg KH
2005-01-12  0:09       ` Luca Falavigna
2005-01-12  6:35         ` Prasanna S Panchamukhi
2005-01-12  9:49           ` Prasanna S Panchamukhi
2005-01-13 23:20       ` Luca Falavigna
2005-01-13 23:34         ` Greg KH
2005-01-17 16:58           ` Luca Falavigna
2005-01-18  6:44             ` Greg KH
2005-01-20 14:13               ` Luca Falavigna
2005-01-14  0:22         ` Stephen Hemminger

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