* [PATCH v2] tracing: fix referencing after memory freeing and refactors code
@ 2013-11-06 19:02 Geyslan G. Bem
2013-11-06 19:20 ` Steven Rostedt
0 siblings, 1 reply; 3+ messages in thread
From: Geyslan G. Bem @ 2013-11-06 19:02 UTC (permalink / raw)
To: kernel-br
Cc: Geyslan G. Bem, Steven Rostedt, Frederic Weisbecker, Ingo Molnar,
open list
In 'system_tr_open()':
Fix possible 'dir' assignment after freeing it.
In both functions:
Restructures logic conditions testing 'tracing_is_disabled()'
return before the others tests.
Signed-off-by: Geyslan G. Bem <geyslan@gmail.com>
---
kernel/trace/trace_events.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 368a4d5..b44a7ea 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1062,6 +1062,9 @@ static int subsystem_open(struct inode *inode, struct file *filp)
struct trace_array *tr;
int ret;
+ if (tracing_is_disabled())
+ return -ENODEV;
+
/* Make sure the system still exists */
mutex_lock(&trace_types_lock);
mutex_lock(&event_mutex);
@@ -1108,6 +1111,9 @@ static int system_tr_open(struct inode *inode, struct file *filp)
struct trace_array *tr = inode->i_private;
int ret;
+ if (tracing_is_disabled())
+ return -ENODEV;
+
if (trace_array_get(tr) < 0)
return -ENODEV;
@@ -1124,11 +1130,12 @@ static int system_tr_open(struct inode *inode, struct file *filp)
if (ret < 0) {
trace_array_put(tr);
kfree(dir);
+ return ret;
}
filp->private_data = dir;
- return ret;
+ return 0;
}
static int subsystem_release(struct inode *inode, struct file *file)
--
1.8.4.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] tracing: fix referencing after memory freeing and refactors code
2013-11-06 19:02 [PATCH v2] tracing: fix referencing after memory freeing and refactors code Geyslan G. Bem
@ 2013-11-06 19:20 ` Steven Rostedt
2013-11-06 20:18 ` Geyslan Gregório Bem
0 siblings, 1 reply; 3+ messages in thread
From: Steven Rostedt @ 2013-11-06 19:20 UTC (permalink / raw)
To: Geyslan G. Bem; +Cc: kernel-br, Frederic Weisbecker, Ingo Molnar, open list
On Wed, 6 Nov 2013 16:02:51 -0300
"Geyslan G. Bem" <geyslan@gmail.com> wrote:
> In 'system_tr_open()':
> Fix possible 'dir' assignment after freeing it.
I'll take this patch, but I'm going to reword the subject and the
change log. The assignment of dir to filp->private_data after dir is
freed is not as bad as it sounds. As we are returning an error,
filp->private_data is never used.
-- Steve
>
> In both functions:
> Restructures logic conditions testing 'tracing_is_disabled()'
> return before the others tests.
>
> Signed-off-by: Geyslan G. Bem <geyslan@gmail.com>
> ---
> kernel/trace/trace_events.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
> index 368a4d5..b44a7ea 100644
> --- a/kernel/trace/trace_events.c
> +++ b/kernel/trace/trace_events.c
> @@ -1062,6 +1062,9 @@ static int subsystem_open(struct inode *inode, struct file *filp)
> struct trace_array *tr;
> int ret;
>
> + if (tracing_is_disabled())
> + return -ENODEV;
> +
> /* Make sure the system still exists */
> mutex_lock(&trace_types_lock);
> mutex_lock(&event_mutex);
> @@ -1108,6 +1111,9 @@ static int system_tr_open(struct inode *inode, struct file *filp)
> struct trace_array *tr = inode->i_private;
> int ret;
>
> + if (tracing_is_disabled())
> + return -ENODEV;
> +
> if (trace_array_get(tr) < 0)
> return -ENODEV;
>
> @@ -1124,11 +1130,12 @@ static int system_tr_open(struct inode *inode, struct file *filp)
> if (ret < 0) {
> trace_array_put(tr);
> kfree(dir);
> + return ret;
> }
>
> filp->private_data = dir;
>
> - return ret;
> + return 0;
> }
>
> static int subsystem_release(struct inode *inode, struct file *file)
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] tracing: fix referencing after memory freeing and refactors code
2013-11-06 19:20 ` Steven Rostedt
@ 2013-11-06 20:18 ` Geyslan Gregório Bem
0 siblings, 0 replies; 3+ messages in thread
From: Geyslan Gregório Bem @ 2013-11-06 20:18 UTC (permalink / raw)
To: Steven Rostedt; +Cc: kernel-br, Frederic Weisbecker, Ingo Molnar, open list
2013/11/6 Steven Rostedt <rostedt@goodmis.org>:
> On Wed, 6 Nov 2013 16:02:51 -0300
> "Geyslan G. Bem" <geyslan@gmail.com> wrote:
>
>> In 'system_tr_open()':
>> Fix possible 'dir' assignment after freeing it.
>
> I'll take this patch, but I'm going to reword the subject and the
> change log. The assignment of dir to filp->private_data after dir is
> freed is not as bad as it sounds. As we are returning an error,
> filp->private_data is never used.
>
> -- Steve
>
>
Ok Steve. Please, do the reword.
>>
>> In both functions:
>> Restructures logic conditions testing 'tracing_is_disabled()'
>> return before the others tests.
>>
>> Signed-off-by: Geyslan G. Bem <geyslan@gmail.com>
>> ---
>> kernel/trace/trace_events.c | 9 ++++++++-
>> 1 file changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
>> index 368a4d5..b44a7ea 100644
>> --- a/kernel/trace/trace_events.c
>> +++ b/kernel/trace/trace_events.c
>> @@ -1062,6 +1062,9 @@ static int subsystem_open(struct inode *inode, struct file *filp)
>> struct trace_array *tr;
>> int ret;
>>
>> + if (tracing_is_disabled())
>> + return -ENODEV;
>> +
>> /* Make sure the system still exists */
>> mutex_lock(&trace_types_lock);
>> mutex_lock(&event_mutex);
>> @@ -1108,6 +1111,9 @@ static int system_tr_open(struct inode *inode, struct file *filp)
>> struct trace_array *tr = inode->i_private;
>> int ret;
>>
>> + if (tracing_is_disabled())
>> + return -ENODEV;
>> +
>> if (trace_array_get(tr) < 0)
>> return -ENODEV;
>>
>> @@ -1124,11 +1130,12 @@ static int system_tr_open(struct inode *inode, struct file *filp)
>> if (ret < 0) {
>> trace_array_put(tr);
>> kfree(dir);
>> + return ret;
>> }
>>
>> filp->private_data = dir;
>>
>> - return ret;
>> + return 0;
>> }
>>
>> static int subsystem_release(struct inode *inode, struct file *file)
>
--
Regards,
Geyslan G. Bem
hackingbits.com
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2013-11-06 19:02 [PATCH v2] tracing: fix referencing after memory freeing and refactors code Geyslan G. Bem
2013-11-06 19:20 ` Steven Rostedt
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