From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422935AbXBHLqW (ORCPT ); Thu, 8 Feb 2007 06:46:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1422939AbXBHLqW (ORCPT ); Thu, 8 Feb 2007 06:46:22 -0500 Received: from ausmtp05.au.ibm.com ([202.81.18.154]:59964 "EHLO ausmtp05.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422935AbXBHLqV (ORCPT ); Thu, 8 Feb 2007 06:46:21 -0500 Message-ID: <45CB0D87.8070808@in.ibm.com> Date: Thu, 08 Feb 2007 17:16:15 +0530 From: Srinivasa Ds User-Agent: Thunderbird 1.5.0.7 (X11/20060918) MIME-Version: 1.0 To: Andrew Morton CC: Frederik Deweerdt , Christoph Hellwig , linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, jkenisto@us.ibm.com, anil.s.keshavamurthy@intel.com, prasanna@in.ibm.com, ananth@in.ibm.com Subject: Re: [RFC] [PATCH] To list all active probes in the system---Take-2 References: <45C85097.1000106@in.ibm.com> <20070206100607.GA10296@infradead.org> <45C856F1.7060403@in.ibm.com> <45C894EA.4060305@in.ibm.com> <20070206145609.GA11249@slug> <45C962C3.2020904@in.ibm.com> <20070207142717.5da4d8d4.akpm@linux-foundation.org> In-Reply-To: <20070207142717.5da4d8d4.akpm@linux-foundation.org> Content-Type: multipart/mixed; boundary="------------010202090703000609090004" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This is a multi-part message in MIME format. --------------010202090703000609090004 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Andrew Morton wrote: > On Wed, 07 Feb 2007 10:55:23 +0530 > Srinivasa Ds wrote: > >> --- linux-2.6.20.orig/fs/debugfs/inode.c >> +++ linux-2.6.20/fs/debugfs/inode.c >> @@ -25,6 +25,7 @@ >> >> if (retval) >> subsystem_unregister(&debug_subsys); >> + debugfs_kprobe_init(); >> return retval; >> } > > eww. Didn't it feel bad when you did that? > > > As this module has a dependency upon debugfs, I'd have thought the > approproate way of expressing that would be to run debugfs_kprobe_init() > at a lower initcall priority than debugfs_init() > >> + >> + if (dir == NULL) >> + return; >> + debugfs_create_file("list", 0444, dir , 0 , &proc_kprobes_operations); >> +} >> + >> __initcall(init_kprobes); > > debugfs_init() already runs at core_initcall level, presumably so that > debugfs clients can use plain old module_init(). > >> +static inline void debugfs_kprobe_init(void) >> +{ >> +} > > In which case we don't need this. Updating the patch according to Andrew's comment. 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 ================================= Signed-off-by: Srinivasa DS --------------010202090703000609090004 Content-Type: text/x-patch; name="list.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="list.patch" kprobes.c | 104 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 104 insertions(+) Index: linux-2.6.20/kernel/kprobes.c =================================================================== --- linux-2.6.20.orig/kernel/kprobes.c +++ linux-2.6.20/kernel/kprobes.c @@ -39,6 +39,8 @@ #include #include #include +#include +#include #include #include #include @@ -815,6 +817,108 @@ static int __init init_kprobes(void) return err; } +#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); +} + +void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos) +{ + return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; +} + +void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) +{ + (*pos)++; + if (*pos >= KPROBE_TABLE_SIZE) + return NULL; + return pos; +} + +void __kprobes kprobe_seq_stop(struct seq_file *f, void *v) +{ + /* Nothing to do */ +} + +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; +} + +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; +} + +module_init(debugfs_kprobe_init); +#endif /* CONFIG_DEBUG_FS */ + __initcall(init_kprobes); EXPORT_SYMBOL_GPL(register_kprobe); --------------010202090703000609090004--