On Wed, Jun 23, 2021 at 04:26:35PM +0200, Pavel Machek wrote:
Hi!
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] [00000010] *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, Pavel -- http://www.livejournal.com/~pavelmachek