RE: [PATCHv1] RDMA/core: Check error status of rdma_find_ndev_for_src_ip_rcu

[Parav Pandit <parav@xxxxxxxxxxxx>]

Hi Doug, Jason,

> -----Original Message-----
> From: Parav Pandit <parav@xxxxxxxxxxxx>
> Sent: Friday, September 21, 2018 10:00 AM
> To: linux-rdma@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> leon@xxxxxxxxxx; jgg@xxxxxxxx; syzkaller-bugs@xxxxxxxxxxxxxxxx; Daniel
> Jurgens <danielj@xxxxxxxxxxxx>; dledford@xxxxxxxxxx
> Cc: Parav Pandit <parav@xxxxxxxxxxxx>
> Subject: [PATCHv1] RDMA/core: Check error status of
> rdma_find_ndev_for_src_ip_rcu
> 
> rdma_find_ndev_for_src_ip_rcu() returns either valid netdev pointer or
> ERR_PTR().
> Instead of checking for NULL, check for error.
> 
> Fixes: caf1e3ae9fa6 ("RDMA/core Introduce and use
> rdma_find_ndev_for_src_ip_rcu")
> Reported-by: syzbot+20c32fa6ff84a2d28c36@xxxxxxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Parav Pandit <parav@xxxxxxxxxxxx>
> ---
>  drivers/infiniband/core/addr.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/infiniband/core/addr.c b/drivers/infiniband/core/addr.c
> index c2ca9e4..3c07eeb 100644
> --- a/drivers/infiniband/core/addr.c
> +++ b/drivers/infiniband/core/addr.c
> @@ -513,8 +513,8 @@ static int rdma_set_src_addr_rcu(struct
> rdma_dev_addr *dev_addr,
>  		 * loopback IP address.
>  		 */
>  		ndev = rdma_find_ndev_for_src_ip_rcu(dev_net(ndev),
> dst_in);
> -		if (!ndev)
> -			return -ENODEV;
> +		if (IS_ERR(ndev))
> +			return PTR_ERR(ndev);
>  	}
> 
>  	return copy_src_l2_addr(dev_addr, dst_in, dst, ndev);
> --
> 1.8.3.1

Can you please review this fix?
I got below report from syzbot that it tested the patch and reproducer didn't trigger.

Report:

syzbot has tested the proposed patch and the reproducer did not trigger  
crash:

Reported-and-tested-by:  
syzbot+20c32fa6ff84a2d28c36@xxxxxxxxxxxxxxxxxxxxxxxxx

Tested on:

commit:         41ab1cb7d1cd RDMA/cma: Introduce and use cma_ib_acquire_de..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git  
for-next
kernel config:  https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsyzkaller.appspot.com%2Fx%2F.config%3Fx%3D112cc1aec8b19ba4&amp;data=02%7C01%7Cparav%40mellanox.com%7Ce0a5662bb6aa4fdee43508d6298c9e60%7Ca652971c7d2e4d9ba6a4d149256f461b%7C0%7C0%7C636742081267605003&amp;sdata=XiJ9F0gNuDvCWt0m2qzS6SbocXbFXIdWEHe%2BaJuvvcM%3D&amp;reserved=0
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
patch:          https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsyzkaller.appspot.com%2Fx%2Fpatch.diff%3Fx%3D10558231400000&amp;data=02%7C01%7Cparav%40mellanox.com%7Ce0a5662bb6aa4fdee43508d6298c9e60%7Ca652971c7d2e4d9ba6a4d149256f461b%7C0%7C0%7C636742081267605003&amp;sdata=da0p6AW3YnXmFVrSaR%2FxSrB%2Bj%2Bml%2B5AXx%2B%2FKG4Kjb1M%3D&amp;reserved=0

Note: testing is done by a robot and is best-effort only.