From: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
To: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@elte.hu>,
lkml <linux-kernel@vger.kernel.org>,
systemtap <systemtap@sources.redhat.com>,
DLE <dle-develop@lists.sourceforge.net>,
Jim Keniston <jkenisto@us.ibm.com>,
Andi Kleen <ak@linux.intel.com>,
Christoph Hellwig <hch@infradead.org>,
"Frank Ch. Eigler" <fche@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Jason Baron <jbaron@redhat.com>,
"K.Prasad" <prasad@linux.vnet.ibm.com>,
Lai Jiangshan <laijs@cn.fujitsu.com>,
Li Zefan <lizf@cn.fujitsu.com>,
Peter Zijlstra <peterz@infradead.org>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Tom Zanussi <tzanussi@gmail.com>
Subject: Re: [BUGFIX] kprobes: prevent re-registration of the same kprobe - take2
Date: Tue, 15 Sep 2009 05:19:00 -0000 [thread overview]
Message-ID: <20090915051307.GB26458@in.ibm.com> (raw)
In-Reply-To: <4AAE6E85.9020002@redhat.com>
On Mon, Sep 14, 2009 at 12:25:41PM -0400, Masami Hiramatsu wrote:
> Ananth N Mavinakayanahalli wrote:
>> On Sun, Sep 13, 2009 at 09:47:39PM -0400, Masami Hiramatsu wrote:
>>> Ananth N Mavinakayanahalli wrote:
>>>> On Fri, Sep 11, 2009 at 05:12:54AM +0200, Frederic Weisbecker wrote:
>>>>> On Thu, Sep 10, 2009 at 07:53:30PM -0400, Masami Hiramatsu wrote:
...
>> +static inline int check_kprobe_rereg(struct kprobe *p)
>> +{
>> + int ret = 0;
>> + struct kprobe *old_p;
>> +
>> + mutex_lock(&kprobe_mutex);
>> + old_p = __get_valid_kprobe(p);
>> + if (old_p == p)
>
> Here, since __get_valid_kprobe(p) will return aggr_kprobe of 'p',
> you just need to check old_p != NULL.
Right!
---
Prevent re-registration of the same kprobe. This situation, though
unlikely, needs to be flagged since it can lead to a system crash if its
not handled.
The core change itself is small, but the helper routine needed to be
moved around a bit; hence the diffstat.
Signed-off-by: Ananth N Mavinakayanahalli<ananth@in.ibm.com>
---
kernel/kprobes.c | 58 ++++++++++++++++++++++++++++++++++++-------------------
1 file changed, 38 insertions(+), 20 deletions(-)
Index: linux-2.6.31/kernel/kprobes.c
===================================================================
--- linux-2.6.31.orig/kernel/kprobes.c
+++ linux-2.6.31/kernel/kprobes.c
@@ -681,6 +681,40 @@ static kprobe_opcode_t __kprobes *kprobe
return (kprobe_opcode_t *)(((char *)addr) + p->offset);
}
+/* Check passed kprobe is valid and return kprobe in kprobe_table. */
+static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p)
+{
+ struct kprobe *old_p, *list_p;
+
+ old_p = get_kprobe(p->addr);
+ if (unlikely(!old_p))
+ return NULL;
+
+ if (p != old_p) {
+ list_for_each_entry_rcu(list_p, &old_p->list, list)
+ if (list_p == p)
+ /* kprobe p is a valid probe */
+ goto valid;
+ return NULL;
+ }
+valid:
+ return old_p;
+}
+
+/* Return error if the kprobe is being re-registered */
+static inline int check_kprobe_rereg(struct kprobe *p)
+{
+ int ret = 0;
+ struct kprobe *old_p;
+
+ mutex_lock(&kprobe_mutex);
+ old_p = __get_valid_kprobe(p);
+ if (old_p)
+ ret = -EINVAL;
+ mutex_unlock(&kprobe_mutex);
+ return ret;
+}
+
int __kprobes register_kprobe(struct kprobe *p)
{
int ret = 0;
@@ -693,6 +727,10 @@ int __kprobes register_kprobe(struct kpr
return -EINVAL;
p->addr = addr;
+ ret = check_kprobe_rereg(p);
+ if (ret)
+ return ret;
+
preempt_disable();
if (!kernel_text_address((unsigned long) p->addr) ||
in_kprobes_functions((unsigned long) p->addr)) {
@@ -762,26 +800,6 @@ out:
}
EXPORT_SYMBOL_GPL(register_kprobe);
-/* Check passed kprobe is valid and return kprobe in kprobe_table. */
-static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p)
-{
- struct kprobe *old_p, *list_p;
-
- old_p = get_kprobe(p->addr);
- if (unlikely(!old_p))
- return NULL;
-
- if (p != old_p) {
- list_for_each_entry_rcu(list_p, &old_p->list, list)
- if (list_p == p)
- /* kprobe p is a valid probe */
- goto valid;
- return NULL;
- }
-valid:
- return old_p;
-}
-
/*
* Unregister a kprobe without a scheduler synchronization.
*/
next prev parent reply other threads:[~2009-09-15 5:19 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-10 23:51 [PATCH tracing/kprobes 0/7] tracing/kprobes: kprobe-based event tracer update and perf support Masami Hiramatsu
2009-09-10 23:51 ` [PATCH tracing/kprobes 3/7] tracing/kprobes: Cleanup kprobe tracer code Masami Hiramatsu
2009-09-11 2:33 ` Daniel Walker
2009-09-11 2:36 ` Frederic Weisbecker
2009-09-10 23:51 ` [PATCH tracing/kprobes 4/7] tracing/kprobes: Add event profiling support Masami Hiramatsu
2009-09-11 3:13 ` Frederic Weisbecker
2009-09-11 16:18 ` Masami Hiramatsu
2009-09-14 3:02 ` Frederic Weisbecker
[not found] ` <4AAE7540.9090009@redhat.com>
2009-09-14 18:55 ` Frederic Weisbecker
[not found] ` <4AAE9B41.3020905@redhat.com>
2009-09-14 21:07 ` Frederic Weisbecker
2009-09-15 4:52 ` Ananth N Mavinakayanahalli
2009-09-11 19:26 ` Masami Hiramatsu
2009-09-14 3:08 ` Frederic Weisbecker
2009-09-13 10:07 ` [BUGFIX] kprobes: prevent re-registration of the same kprobe Ananth N Mavinakayanahalli
[not found] ` <4AADA0BB.4030307@redhat.com>
2009-09-14 10:05 ` [BUGFIX] kprobes: prevent re-registration of the same kprobe - take2 Ananth N Mavinakayanahalli
[not found] ` <4AAE6E85.9020002@redhat.com>
2009-09-15 5:19 ` Ananth N Mavinakayanahalli [this message]
2009-09-16 23:52 ` Masami Hiramatsu
2009-09-10 23:51 ` [PATCH tracing/kprobes 1/7] x86/ptrace: Fix regs_get_argument_nth() to add correct offset Masami Hiramatsu
2009-09-11 1:43 ` Steven Rostedt
2009-09-10 23:51 ` [PATCH tracing/kprobes 2/7] tracing/kprobes: Fix probe offset to be unsigned Masami Hiramatsu
2009-09-10 23:51 ` [PATCH tracing/kprobes 5/7] tracing/kprobes: Add argument name support Masami Hiramatsu
2009-09-11 14:08 ` Steven Rostedt
2009-09-11 16:07 ` Masami Hiramatsu
2009-09-11 16:28 ` Masami Hiramatsu
2009-09-10 23:52 ` [PATCH tracing/kprobes 6/7] tracing/kprobes: Show event name in trace output Masami Hiramatsu
2009-09-10 23:52 ` [PATCH tracing/kprobes 7/7] tracing/kprobes: Support custom subsystem for each kprobe event Masami Hiramatsu
2009-09-11 1:33 ` [PATCH tracing/kprobes 0/7] tracing/kprobes: kprobe-based event tracer update and perf support Frederic Weisbecker
2009-09-11 1:45 ` Steven Rostedt
2009-09-11 15:59 ` Masami Hiramatsu
2009-09-14 3:00 ` Frederic Weisbecker
[not found] ` <4AAE7A5D.8010503@redhat.com>
2009-09-14 20:53 ` Frederic Weisbecker
[not found] ` <4AAEB149.2070300@redhat.com>
2009-09-14 21:09 ` Frederic Weisbecker
2009-09-11 19:03 ` Frank Ch. Eigler
2009-09-11 19:07 ` Christoph Hellwig
2009-09-11 19:51 ` Mark Wielaard
[not found] ` <20090911200317.GA3827@infradead.org>
2009-09-12 1:20 ` Masami Hiramatsu
2009-09-11 19:15 ` Frederic Weisbecker
2009-09-11 15:36 ` Frederic Weisbecker
2009-09-11 21:44 ` Masami Hiramatsu
2009-09-14 2:23 ` Frederic Weisbecker
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