2019-07-21 18:34:16

by Hariprasad Kelam

Subject: [PATCH] irqchip/tango: Add NULL check after memory operation

Add NULL check after kzalloc operation.

Fix below issue reported by coccicheck
./drivers/irqchip/irq-tango.c:189:1-5: alloc with no test, possible
model on line 193

Signed-off-by: Hariprasad Kelam <[email protected]>
---
drivers/irqchip/irq-tango.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/irqchip/irq-tango.c b/drivers/irqchip/irq-tango.c
index 34290f0..761b9fa 100644
--- a/drivers/irqchip/irq-tango.c
+++ b/drivers/irqchip/irq-tango.c
@@ -187,6 +187,8 @@ static int __init tangox_irq_init(void __iomem *base, struct resource *baseres,
panic("%pOFn: failed to get address", node);

chip = kzalloc(sizeof(*chip), GFP_KERNEL);
+ if (!chip)
+ return -ENOMEM;
chip->ctl = res.start - baseres->start;
chip->base = base;

--
2.7.4

2019-07-22 08:55:32

by Måns Rullgård

Subject: Re: [PATCH] irqchip/tango: Add NULL check after memory operation

Hariprasad Kelam <[email protected]> writes:

> Add NULL check after kzalloc operation.
>
> Fix below issue reported by coccicheck
> ./drivers/irqchip/irq-tango.c:189:1-5: alloc with no test, possible
> model on line 193
>
> Signed-off-by: Hariprasad Kelam <[email protected]>
> ---
> drivers/irqchip/irq-tango.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/irqchip/irq-tango.c b/drivers/irqchip/irq-tango.c
> index 34290f0..761b9fa 100644
> --- a/drivers/irqchip/irq-tango.c
> +++ b/drivers/irqchip/irq-tango.c
> @@ -187,6 +187,8 @@ static int __init tangox_irq_init(void __iomem *base, struct resource *baseres,
> panic("%pOFn: failed to get address", node);
>
> chip = kzalloc(sizeof(*chip), GFP_KERNEL);
> + if (!chip)
> + return -ENOMEM;
> chip->ctl = res.start - baseres->start;
> chip->base = base;
>
> --

Nothing checks the return value of that function, so bad things will
still happen, only more confusing to debug. If you really want to
"fix" this, you should either:

- Simply panic() like the other error cases. If anything here fails,
the system will not work anyway.

- Replace the panic() calls with error returns and check the return
value in tangox_of_irq_init(). The system will still end up unusable.

--
M?ns Rullg?rd