linux-toradex.git/kernel/bpf/syscall.c, branch v5.10-rc1

bpf: Remove unneeded break

2020-10-19T18:40:21+00:00

A break is not needed if it is preceded by a return.

Signed-off-by: Tom Rix 
Signed-off-by: Daniel Borkmann 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20201019173846.1021-1-trix@redhat.com

bpf: Deref map in BPF_PROG_BIND_MAP when it's already used

2020-10-03T02:21:25+00:00

We are missing a deref for the case when we are doing BPF_PROG_BIND_MAP
on a map that's being already held by the program.
There is 'if (ret) bpf_map_put(map)' below which doesn't trigger
because we don't consider this an error.
Let's add missing bpf_map_put() for this specific condition.

Fixes: ef15314aa5de ("bpf: Add BPF_PROG_BIND_MAP syscall")
Reported-by: Alexei Starovoitov 
Signed-off-by: Stanislav Fomichev 
Signed-off-by: Alexei Starovoitov 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20201003002544.3601440-1-sdf@google.com

bpf: Support attaching freplace programs to multiple attach points

2020-09-29T20:09:24+00:00

This enables support for attaching freplace programs to multiple attach
points. It does this by amending the UAPI for bpf_link_Create with a target
btf ID that can be used to supply the new attachment point along with the
target program fd. The target must be compatible with the target that was
supplied at program load time.

The implementation reuses the checks that were factored out of
check_attach_btf_id() to ensure compatibility between the BTF types of the
old and new attachment. If these match, a new bpf_tracing_link will be
created for the new attach target, allowing multiple attachments to
co-exist simultaneously.

The code could theoretically support multiple-attach of other types of
tracing programs as well, but since I don't have a use case for any of
those, there is no API support for doing so.

Signed-off-by: Toke Høiland-Jørgensen 
Signed-off-by: Alexei Starovoitov 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/160138355169.48470.17165680973640685368.stgit@toke.dk

bpf: Move prog->aux->linked_prog and trampoline into bpf_link on attach

2020-09-29T20:09:23+00:00

In preparation for allowing multiple attachments of freplace programs, move
the references to the target program and trampoline into the
bpf_tracing_link structure when that is created. To do this atomically,
introduce a new mutex in prog->aux to protect writing to the two pointers
to target prog and trampoline, and rename the members to make it clear that
they are related.

With this change, it is no longer possible to attach the same tracing
program multiple times (detaching in-between), since the reference from the
tracing program to the target disappears on the first attach. However,
since the next patch will let the caller supply an attach target, that will
also make it possible to attach to the same place multiple times.

Signed-off-by: Toke Høiland-Jørgensen 
Signed-off-by: Alexei Starovoitov 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/160138355059.48470.2503076992210324984.stgit@toke.dk

bpf: Enable BPF_PROG_TEST_RUN for raw_tracepoint

2020-09-28T19:52:36+00:00

Add .test_run for raw_tracepoint. Also, introduce a new feature that runs
the target program on a specific CPU. This is achieved by a new flag in
bpf_attr.test, BPF_F_TEST_RUN_ON_CPU. When this flag is set, the program
is triggered on cpu with id bpf_attr.test.cpu. This feature is needed for
BPF programs that handle perf_event and other percpu resources, as the
program can access these resource locally.

Signed-off-by: Song Liu 
Signed-off-by: Daniel Borkmann 
Acked-by: John Fastabend 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20200925205432.1777-2-songliubraving@fb.com

Revert "bpf: Fix potential call bpf_link_free() in atomic context"

2020-09-24T02:14:11+00:00

This reverts commit 31f23a6a181c81543b10a1a9056b0e6c7ef1c747.

This change made many selftests/bpf flaky: flow_dissector, sk_lookup, sk_assign and others.
There was no issue in the code.

Signed-off-by: Alexei Starovoitov

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

2020-09-23T20:11:11+00:00

Alexei Starovoitov says:

====================
pull-request: bpf-next 2020-09-23

The following pull-request contains BPF updates for your *net-next* tree.

We've added 95 non-merge commits during the last 22 day(s) which contain
a total of 124 files changed, 4211 insertions(+), 2040 deletions(-).

The main changes are:

1) Full multi function support in libbpf, from Andrii.

2) Refactoring of function argument checks, from Lorenz.

3) Make bpf_tail_call compatible with functions (subprograms), from Maciej.

4) Program metadata support, from YiFei.

5) bpf iterator optimizations, from Yonghong.
====================

Signed-off-by: David S. Miller

bpf: Fix potential call bpf_link_free() in atomic context

2020-09-21T19:20:17+00:00

The in_atomic() macro cannot always detect atomic context, in particular,
it cannot know about held spinlocks in non-preemptible kernels. Although,
there is no user call bpf_link_put() with holding spinlock now, be on the
safe side, so we can avoid this in the future.

Signed-off-by: Muchun Song 
Signed-off-by: Daniel Borkmann 
Acked-by: Song Liu 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20200917074453.20621-1-songmuchun@bytedance.com

bpf: Add BPF_PROG_BIND_MAP syscall

2020-09-16T01:28:27+00:00

This syscall binds a map to a program. Returns success if the map is
already bound to the program.

Signed-off-by: YiFei Zhu 
Signed-off-by: Stanislav Fomichev 
Signed-off-by: Alexei Starovoitov 
Acked-by: Andrii Nakryiko 
Cc: YiFei Zhu 
Link: https://lore.kernel.org/bpf/20200915234543.3220146-3-sdf@google.com

bpf: Mutex protect used_maps array and count

2020-09-16T01:28:27+00:00

To support modifying the used_maps array, we use a mutex to protect
the use of the counter and the array. The mutex is initialized right
after the prog aux is allocated, and destroyed right before prog
aux is freed. This way we guarantee it's initialized for both cBPF
and eBPF.

Signed-off-by: YiFei Zhu 
Signed-off-by: Stanislav Fomichev 
Signed-off-by: Alexei Starovoitov 
Acked-by: Andrii Nakryiko 
Cc: YiFei Zhu 
Link: https://lore.kernel.org/bpf/20200915234543.3220146-2-sdf@google.com