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SubjectRe: [PATCH v7 bpf-next 00/14] bpf: cgroup local storage
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On 08/02/2018 11:27 PM, Roman Gushchin wrote:
> This patchset implements cgroup local storage for bpf programs.
> The main idea is to provide a fast accessible memory for storing
> various per-cgroup data, e.g. number of transmitted packets.
>
> Cgroup local storage looks as a special type of map for userspace,
> and is accessible using generic bpf maps API for reading and
> updating of the data. The (cgroup inode id, attachment type) pair
> is used as a map key.
>
> A user can't create new entries or destroy existing entries;
> it happens automatically when a user attaches/detaches a bpf program
> to a cgroup.
>
> From a bpf program's point of view, cgroup storage is accessible
> without lookup using the special get_local_storage() helper function.
> It takes a map fd as an argument. It always returns a valid pointer
> to the corresponding memory area.
>
> To implement such a lookup-free access a pointer to the cgroup
> storage is saved for an attachment of a bpf program to a cgroup,
> if required by the program. Before running the program, it's saved
> in a special global per-cpu variable, which is accessible from the
> get_local_storage() helper.
>
> This patchset implement only cgroup local storage, however the API
> is intentionally made extensible to support other local storage types
> further: e.g. thread local storage, socket local storage, etc.
>
> v7->v6:
> - fixed a use-after-free bug, caused by not clearing
> prog->aux->cgroup_storage pointer after releasing the map
>
> v6->v5:
> - fixed an error with returning -EINVAL instead of a pointer
>
> v5->v4:
> - fixed an issue in verifier (test that flags == 0 properly)
> - added a corresponding test
> - added a note about synchronization, sync docs to tools/uapi/...
> - switched the cgroup test to use XADD
> - added a check for attr->max_entries to be 0, and atter->max_flags
> to be sane
> - use bpf_uncharge_memlock() in bpf_uncharge_memlock()
> - rebased to bpf-next
>
> v4->v3:
> - fixed a leak in cgroup attachment code (discovered by Daniel)
> - cgroup storage map will be released if the corresponding
> bpf program failed to load by any reason
> - introduced bpf_uncharge_memlock() helper
>
> v3->v2:
> - fixed more build and sparse issues
> - rebased to bpf-next
>
> v2->v1:
> - fixed build issues
> - removed explicit rlimit calls in patch 14
> - rebased to bpf-next
>
> Signed-off-by: Roman Gushchin <guro@fb.com>
> Cc: Alexei Starovoitov <ast@kernel.org>
> Cc: Martin KaFai Lau <kafai@fb.com>
>
> Roman Gushchin (14):
> bpf: add ability to charge bpf maps memory dynamically
> bpf: introduce cgroup storage maps
> bpf: pass a pointer to a cgroup storage using pcpu variable
> bpf: allocate cgroup storage entries on attaching bpf programs
> bpf: extend bpf_prog_array to store pointers to the cgroup storage
> bpf/verifier: introduce BPF_PTR_TO_MAP_VALUE
> bpf: don't allow create maps of cgroup local storages
> bpf: introduce the bpf_get_local_storage() helper function
> bpf: sync bpf.h to tools/
> bpftool: add support for CGROUP_STORAGE maps
> bpf/test_run: support cgroup local storage
> selftests/bpf: add verifier cgroup storage tests
> selftests/bpf: add a cgroup storage test
> samples/bpf: extend test_cgrp2_attach2 test to use cgroup storage

Tossed the old series from bpf-next and replaced with this one which fixes
the syzkaller issue, thanks Roman!

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