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From: Carsten Emde on 24 Feb 2010 02:20
On 02/22/2010 02:27 PM, Dan Carpenter wrote:
> index_ptr needs to be freed on the error path.
>
> Signed-off-by: Dan Carpenter <error27(a)gmail.com>
>
> diff --git a/kernel/trace/latency_hist.c b/kernel/trace/latency_hist.c
> index b3b5ea2..8edc70c 100644
> --- a/kernel/trace/latency_hist.c
> +++ b/kernel/trace/latency_hist.c
> @@ -204,8 +204,10 @@ static void *l_start(struct seq_file *m, loff_t *pos)
> , my_hist->beyond_hist_bound_samples
> , MAX_ENTRY_NUM, "samples");
> }
> - if (index >= MAX_ENTRY_NUM)
> + if (index >= MAX_ENTRY_NUM) {
> + kfree(index_ptr);
> return NULL;
> + }
>
> *index_ptr = index;
> return index_ptr;
Thanks a lot for spotting this leak. We even don't need to allocate the
memory, if index >= MAX_ENTRY_NUM.

This patch applies to 2.6.31.12-rt21 and 2.6.33-rc8-rt (rt/head).

Signed-off-by: Carsten Emde <C.Emde(a)osadl.org>

Index: head/kernel/trace/latency_hist.c
===================================================================
--- head.orig/kernel/trace/latency_hist.c
+++ head/kernel/trace/latency_hist.c
@@ -218,13 +218,10 @@ void notrace latency_hist(int latency_ty

static void *l_start(struct seq_file *m, loff_t *pos)
{
- loff_t *index_ptr = kmalloc(sizeof(loff_t), GFP_KERNEL);
+ loff_t *index_ptr = NULL;
loff_t index = *pos;
struct hist_data *my_hist = m->private;

- if (!index_ptr)
- return NULL;
-
if (index == 0) {
char minstr[32], avgstr[32], maxstr[32];

@@ -263,10 +260,12 @@ static void *l_start(struct seq_file *m,
MAX_ENTRY_NUM - my_hist->offset,
"samples");
}
- if (index >= MAX_ENTRY_NUM)
- return NULL;
+ if (index < MAX_ENTRY_NUM) {
+ index_ptr = kmalloc(sizeof(loff_t), GFP_KERNEL);
+ if (index_ptr)
+ *index_ptr = index;
+ }

- *index_ptr = index;
return index_ptr;
}

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