2022-02-28 18:10:18

by Jakob Koschel

Subject: [PATCH] powerpc/sysdev: fix incorrect use to determine if list is empty

'gtm' will *always* be set by list_for_each_entry().
It is incorrect to assume that the iterator value will be NULL if the
list is empty.

Instead of checking the pointer it should be checked if
the list is empty.

Fixes: 83ff9dcf375c ("powerpc/sysdev: implement FSL GTM support")
Signed-off-by: Jakob Koschel <[email protected]>
---
arch/powerpc/sysdev/fsl_gtm.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/sysdev/fsl_gtm.c b/arch/powerpc/sysdev/fsl_gtm.c
index 8963eaffb1b7..39186ad6b3c3 100644
--- a/arch/powerpc/sysdev/fsl_gtm.c
+++ b/arch/powerpc/sysdev/fsl_gtm.c
@@ -86,7 +86,7 @@ static LIST_HEAD(gtms);
*/
struct gtm_timer *gtm_get_timer16(void)
{
- struct gtm *gtm = NULL;
+ struct gtm *gtm;
int i;

list_for_each_entry(gtm, &gtms, list_node) {
@@ -103,7 +103,7 @@ struct gtm_timer *gtm_get_timer16(void)
spin_unlock_irq(&gtm->lock);
}

- if (gtm)
+ if (!list_empty(&gtms))
return ERR_PTR(-EBUSY);
return ERR_PTR(-ENODEV);
}

base-commit: 7ee022567bf9e2e0b3cd92461a2f4986ecc99673
--
2.25.1

2022-03-08 14:22:48

by Michael Ellerman

Subject: Re: [PATCH] powerpc/sysdev: fix incorrect use to determine if list is empty

On Mon, 28 Feb 2022 15:24:33 +0100, Jakob Koschel wrote:
> 'gtm' will *always* be set by list_for_each_entry().
> It is incorrect to assume that the iterator value will be NULL if the
> list is empty.
>
> Instead of checking the pointer it should be checked if
> the list is empty.
>
> [...]

Applied to powerpc/next.

[1/1] powerpc/sysdev: fix incorrect use to determine if list is empty
https://git.kernel.org/powerpc/c/fa1321b11bd01752f5be2415e74a0e1a7c378262

cheers