Re: [v2] net:ethernet:cavium:octeon:octeon_mgmt: Handle return NULL error from devm_ioremap

From: arvind Yadav
Date: Wed Dec 14 2016 - 13:07:23 EST

Yes, I have seen this error. We have a device with very less memory.
Basically it's OMAP2 board. We have to port Android L on this.
It's has 3.10 kernel version. In this device, we were getting Page allocation failure.
Vmalloc size was not enough to run all application. So we have decide to
increase vmalloc reserve space. once we increases Vmalloc space.
We start getting ioremap falilure. Kernel is getting NULL-pointer dereference error.

Here, It's just check to avoid any kernel crash because of ioremap failure.
We can keep this check to avoid this kind of scenario.


On Wednesday 14 December 2016 11:02 PM, David Daney wrote:
On 12/14/2016 08:25 AM, Arvind Yadav wrote:
Here, If devm_ioremap will fail. It will return NULL.
Kernel can run into a NULL-pointer dereference.
This error check will avoid NULL pointer dereference.

Have you ever seen this failure in the wild?

How was the patch tested?

David Daney

Signed-off-by: Arvind Yadav <arvind.yadav.cs@xxxxxxxxx>
drivers/net/ethernet/cavium/octeon/octeon_mgmt.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/net/ethernet/cavium/octeon/octeon_mgmt.c b/drivers/net/ethernet/cavium/octeon/octeon_mgmt.c
index 4ab404f..33c2fec 100644
--- a/drivers/net/ethernet/cavium/octeon/octeon_mgmt.c
+++ b/drivers/net/ethernet/cavium/octeon/octeon_mgmt.c
@@ -1479,6 +1479,12 @@ static int octeon_mgmt_probe(struct platform_device *pdev)
p->agl = (u64)devm_ioremap(&pdev->dev, p->agl_phys, p->agl_size);
p->agl_prt_ctl = (u64)devm_ioremap(&pdev->dev, p->agl_prt_ctl_phys,
+ if (!p->mix || !p->agl || !p->agl_prt_ctl) {
+ dev_err(&pdev->dev, "failed to map I/O memory\n");
+ result = -ENOMEM;
+ goto err;
+ }