> > > This control logic is a bit strange.
> > > When change_tramp() fails we should not printk() the output variable.
> > >
> > > if (pid < 0){
> > > free(output);
> > > return;
> > > }
> > >
> > > Would be much cleaner.
> >
> > I just didn't want to clone this free-return stuff. So, what you
> > proposing is like this:
> > ------------
> > ...
> > output = uml_kmalloc(output_len, UM_GFP_KERNEL);
> > if (output == NULL)
> > printk(UM_KERN_ERR "change : failed to allocate output "
> > "buffer\n");
> >
> > pid = change_tramp(argv, output, output_len);
> > if (pid < 0) {
> > free(output); <---------- I'm not sure but
> > 'output' can be NULL here.
> > return;
> > }
> >
> > if (output != NULL) {
> > printk("%s", output);
> > kfree(output);
> > }
> > }
> > ------------
> >
> > I was trying to print 'output' only in case change_tramp is
> > successful. That's the old logic. And at the same time perform free
> > only in case output is not NULL.
>
> Why?
> Freeing a NULL pointer is perfectly fine.
I should agree that something that you propose has better readability.
So, here is updated patch.
Thanks
---
>From b0c5ca0336cc94b2fda251e0da7918394e59c5cd Mon Sep 17 00:00:00 2001
From: Vitaliy Ivanov <vitaliva...@gmail.com>
Date: Fri, 8 Jul 2011 14:54:29 +0300
Subject: [PATCH] uml: drivers/net_user.c memory leak fix
Perform memory cleanup on exit.
On receiving invalid 'pid' we still should clean 'output' variable.
Signed-off-by: Vitaliy Ivanov <vitaliva...@gmail.com>
Signed-off-by: Richard Weinberger <rich...@nod.at>
---
arch/um/drivers/net_user.c | 5 ++++-
1 files changed, 4 insertions(+), 1 deletions(-)
diff --git a/arch/um/drivers/net_user.c b/arch/um/drivers/net_user.c
index 9415dd9..5201188 100644
--- a/arch/um/drivers/net_user.c
+++ b/arch/um/drivers/net_user.c
@@ -228,7 +228,10 @@ static void change(char *dev, char *what, unsigned char
*addr,
"buffer\n");
pid = change_tramp(argv, output, output_len);
- if (pid < 0) return;
+ if (pid < 0) {
+ kfree(output);
+ return;
+ }
if (output != NULL) {
printk("%s", output);
--
1.7.0.4
------------------------------------------------------------------------------
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