2008-07-21 07:59:23

by Julia Lawall

Subject: [PATCH 6/7] drivers/video: Release mutex in error handling code

From: Julia Lawall <[email protected]>

The mutex is released on a successful return, so it would seem that it
should be released on an error return as well.

The semantic patch finds this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@
expression l;
@@

mutex_lock(l);
... when != mutex_unlock(l)
when any
when strict
(
if (...) { ... when != mutex_unlock(l)
+ mutex_unlock(l);
return ...;
}
|
mutex_unlock(l);
)
// </smpl>

Signed-off-by: Julia Lawall <[email protected]>

---
drivers/video/arkfb.c | 9 +++------
drivers/video/vt8623fb.c | 9 +++------
2 files changed, 6 insertions(+), 12 deletions(-)

diff -u -p a/drivers/video/arkfb.c b/drivers/video/arkfb.c
--- a/drivers/video/arkfb.c
+++ b/drivers/video/arkfb.c
@@ -1126,11 +1126,8 @@ static int ark_pci_resume (struct pci_de
acquire_console_sem();
mutex_lock(&(par->open_lock));

- if (par->ref_count == 0) {
- mutex_unlock(&(par->open_lock));
- release_console_sem();
- return 0;
- }
+ if (par->ref_count == 0)
+ goto fail;

pci_set_power_state(dev, PCI_D0);
pci_restore_state(dev);
@@ -1143,8 +1140,8 @@ static int ark_pci_resume (struct pci_de
arkfb_set_par(info);
fb_set_suspend(info, 0);

- mutex_unlock(&(par->open_lock));
fail:
+ mutex_unlock(&(par->open_lock));
release_console_sem();
return 0;
}
diff -u -p a/drivers/video/vt8623fb.c b/drivers/video/vt8623fb.c
--- a/drivers/video/vt8623fb.c
+++ b/drivers/video/vt8623fb.c
@@ -853,11 +853,8 @@ static int vt8623_pci_resume(struct pci_
acquire_console_sem();
mutex_lock(&(par->open_lock));

- if (par->ref_count == 0) {
- mutex_unlock(&(par->open_lock));
- release_console_sem();
- return 0;
- }
+ if (par->ref_count == 0)
+ goto fail;

pci_set_power_state(dev, PCI_D0);
pci_restore_state(dev);
@@ -870,8 +867,8 @@ static int vt8623_pci_resume(struct pci_
vt8623fb_set_par(info);
fb_set_suspend(info, 0);

- mutex_unlock(&(par->open_lock));
fail:
+ mutex_unlock(&(par->open_lock));
release_console_sem();

return 0;

2008-07-22 04:14:36

by Krzysztof Helt

Subject: Re: [Linux-fbdev-devel] [PATCH 6/7] drivers/video: Release mutex in error handling code

On Mon, 21 Jul 2008 09:58:55 +0200 (CEST)
Julia Lawall <[email protected]> wrote:

> From: Julia Lawall <[email protected]>
>
> The mutex is released on a successful return, so it would seem that it
> should be released on an error return as well.
>
> The semantic patch finds this problem is as follows:
> (http://www.emn.fr/x-info/coccinelle/)
>
> // <smpl>
> @@
> expression l;
> @@
>
> mutex_lock(l);
> ... when != mutex_unlock(l)
> when any
> when strict
> (
> if (...) { ... when != mutex_unlock(l)
> + mutex_unlock(l);
> return ...;
> }
> |
> mutex_unlock(l);
> )
> // </smpl>
>
> Signed-off-by: Julia Lawall <[email protected]>
>
> ---

Acked-by: Krzysztof Helt <[email protected]>

----------------------------------------------------------------------
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2008-07-22 08:34:49

by Ondrej Zajicek

Subject: Re: [Linux-fbdev-devel] [PATCH 6/7] drivers/video: Release mutex in error handling code

On Mon, Jul 21, 2008 at 09:58:55AM +0200, Julia Lawall wrote:
> From: Julia Lawall <[email protected]>
>
> The mutex is released on a successful return, so it would seem that it
> should be released on an error return as well.
...
> Signed-off-by: Julia Lawall <[email protected]>

Acked-by: Ondrej Zajicek <[email protected]>

--
Elen sila lumenn' omentielvo

Ondrej 'SanTiago' Zajicek (email: [email protected])
OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net)
"To err is human -- to blame it on a computer is even more so."