Re: [PATCH] [RFC] bpf: tracing: new helper bpf_get_current_cgroup_ino
From: Daniel Borkmann <daniel@iogearbox.net>
Date: 2018-05-23 08:57:10
Also in:
cgroups, lkml
On 05/23/2018 06:31 AM, Y Song wrote:
On Tue, May 22, 2018 at 8:35 PM, Alexei Starovoitov [off-list ref] wrote:quoted
On Tue, May 22, 2018 at 08:33:24PM -0700, Y Song wrote:quoted
+ struct cgroup *cgrp = task_dfl_cgroup(current); + if (!cgrp) + return -EINVAL;why this check is needed?No reason :-) Originally I am concerned whether it is possible cgrp could be NULL. By looking at the code, it SEEMS to me that it could not be NULL, but I am not 100% sure (as I am not a cgroup expert). Since you are asking, probably means it cannot be NULL, so will remove it in formal upstream patch.
Aside from this the cgrp->kn->id.id is also u64, so overlapping this with error codes we'll get into a similar issue as with bpf_perf_event_read().