From: sdf@google.com
To: Pu Lehui <pulehui@huaweicloud.com>
Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Quentin Monnet <quentin@isovalent.com>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>, Hao Luo <haoluo@google.com>,
Jiri Olsa <jolsa@kernel.org>, Pu Lehui <pulehui@huawei.com>
Subject: Re: [PATCH bpf-next v2 0/2] Fix cgroup attach flags being assigned to effective progs
Date: Thu, 8 Sep 2022 10:28:06 -0700 [thread overview]
Message-ID: <YxomJlABk3fzQ9bQ@google.com> (raw)
In-Reply-To: <20220908145304.3436139-1-pulehui@huaweicloud.com>
On 09/08, Pu Lehui wrote:
> From: Pu Lehui <pulehui@huawei.com>
> When root-cgroup attach multi progs and sub-cgroup attach a
> override prog, bpftool will display incorrectly for the attach
> flags of the sub-cgroup’s effective progs:
> $ bpftool cgroup tree /sys/fs/cgroup effective
> CgroupPath
> ID AttachType AttachFlags Name
> /sys/fs/cgroup
> 6 cgroup_sysctl multi sysctl_tcp_mem
> 13 cgroup_sysctl multi sysctl_tcp_mem
> /sys/fs/cgroup/cg1
> 20 cgroup_sysctl override sysctl_tcp_mem
> 6 cgroup_sysctl override sysctl_tcp_mem <- wrong
> 13 cgroup_sysctl override sysctl_tcp_mem <- wrong
> /sys/fs/cgroup/cg1/cg2
> 20 cgroup_sysctl sysctl_tcp_mem
> 6 cgroup_sysctl sysctl_tcp_mem
> 13 cgroup_sysctl sysctl_tcp_mem
> For cg1, obviously, the attach flags of prog6 and prog13 can not be
> OVERRIDE, and the attach flags of prog6 and prog13 is meaningless for
> cg1. We only need to care the attach flags of prog which attached to
> cg1, other progs attach flags should be omit. After these patches,
> the above situation will show as bellow:
> $ bpftool cgroup tree /sys/fs/cgroup effective
> CgroupPath
> ID AttachType AttachFlags Name
> /sys/fs/cgroup
> 6 cgroup_sysctl multi sysctl_tcp_mem
> 13 cgroup_sysctl multi sysctl_tcp_mem
> /sys/fs/cgroup/cg1
> 20 cgroup_sysctl override sysctl_tcp_mem
> 6 cgroup_sysctl sysctl_tcp_mem
> 13 cgroup_sysctl sysctl_tcp_mem
> /sys/fs/cgroup/cg1/cg2
> 20 cgroup_sysctl sysctl_tcp_mem
> 6 cgroup_sysctl sysctl_tcp_mem
> 13 cgroup_sysctl sysctl_tcp_mem
> v2:
> - Limit prog_cnt to avoid overflow. (John)
> - Add more detail message.
John also raised a good question in v1: the flags don't seem to
make sense when requesting effective list. So maybe not export them
at all?
> v1:
> https://lore.kernel.org/bpf/20220820120234.2121044-1-pulehui@huawei.com
> Pu Lehui (2):
> bpf, cgroup: Fix attach flags being assigned to effective progs
> bpftool: Fix cgroup attach flags being assigned to effective progs
> kernel/bpf/cgroup.c | 5 ++++-
> tools/bpf/bpftool/cgroup.c | 9 +++------
> 2 files changed, 7 insertions(+), 7 deletions(-)
> --
> 2.25.1
next prev parent reply other threads:[~2022-09-08 17:30 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-08 14:53 [PATCH bpf-next v2 0/2] Fix cgroup attach flags being assigned to effective progs Pu Lehui
2022-09-08 14:53 ` [PATCH bpf-next v2 1/2] bpf, cgroup: Fix " Pu Lehui
2022-09-08 14:53 ` [PATCH bpf-next v2 2/2] bpftool: Fix cgroup " Pu Lehui
2022-09-08 17:28 ` sdf [this message]
2022-09-08 19:13 ` [PATCH bpf-next v2 0/2] " Martin KaFai Lau
2022-09-13 13:35 ` Pu Lehui
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