Re: [PATCH 5.10 045/146] net: make get_net_ns return error if NET_NS is disabled

From: Pavel Machek
Date: Wed Jun 23 2021 - 10:26:38 EST


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?

Best regards,
Pavel

--
http://www.livejournal.com/~pavelmachek

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