bpf map collision

bpf map collision

[Rao Shoaib]

Hi,

Can someone please explain to me the magic that makes the map accessed
in the program running in the kernel same as one created in the user
program. What is the use of the map name? can there be collision if say
two separate processes load the exact same program.

Thanks,

Shoaib

Re: bpf map collision

[Andrii Nakryiko]

On Mon, Jun 17, 2024 at 3:22 AM Rao Shoaib <rao.shoaib@oracle.com> wrote:
>
> Hi,
>
> Can someone please explain to me the magic that makes the map accessed
> in the program running in the kernel same as one created in the user
> program. What is the use of the map name? can there be collision if say
> two separate processes load the exact same program.

It's not magic. Map name is just a hint and there is no uniqueness
requirement (and also nothing in the kernel relies on map name).
Everything is working based on file descriptors (FDs). When a BPF map
is created, kernel returns FD to user space. User space uses that FD
to identify the BPF map.

>
> Thanks,
>
> Shoaib
>
>