Re: [PATCH 5.10 045/146] net: make get_net_ns return error if NET_NS is disabled
From: Changbin Du
Date: Sun Jun 27 2021 - 05:01:35 EST
On Wed, Jun 23, 2021 at 04:26:35PM +0200, Pavel Machek wrote:
> > There is a panic in socket ioctl cmd SIOCGSKNS when NET_NS is not enabled.
> > The reason is that nsfs tries to access ns->ops but the proc_ns_operations
> > is not implemented in this case.
> > [7.670023] Unable to handle kernel NULL pointer dereference at virtual address 00000010
> > [7.670268] pgd = 32b54000
> > [7.670544]  *pgd=00000000
> > [7.671861] Internal error: Oops: 5 [#1] SMP ARM
> > [7.672315] Modules linked in:
> > [7.672918] CPU: 0 PID: 1 Comm: systemd Not tainted 5.13.0-rc3-00375-g6799d4f2da49 #16
> > [7.673309] Hardware name: Generic DT based system
> > [7.673642] PC is at nsfs_evict+0x24/0x30
> > [7.674486] LR is at clear_inode+0x20/0x9c
> > The same to tun SIOCGSKNS command.
> > To fix this problem, we make get_net_ns() return -EINVAL when NET_NS is
> > disabled. Meanwhile move it to right place net/core/net_namespace.c.
> -EINVAL sounds like wrong error code for valid operation kernel was
> configured to do. -ENOTSUPP?
This is to align with the existing code which returns -EINVAL.
For the issue we fixed, yes, -EOPNOTSUPP (not -ENOTSUPP) should be better.
> Best regards,