linux-stable.git/tools/lib/bpf, branch v5.14.7

libbpf: Fix race when pinning maps in parallel

2021-09-18T11:43:43+00:00

[ Upstream commit 043c5bb3c4f43670ab4fea0b847373ab42d25f3e ]

When loading in parallel multiple programs which use the same to-be
pinned map, it is possible that two instances of the loader will call
bpf_object__create_maps() at the same time. If the map doesn't exist
when both instances call bpf_object__reuse_map(), then one of the
instances will fail with EEXIST when calling bpf_map__pin().

Fix the race by retrying reusing a map if bpf_map__pin() returns
EEXIST. The fix is similar to the one in iproute2: e4c4685fd6e4 ("bpf:
Fix race condition with map pinning").

Before retrying the pinning, we don't do any special cleaning of an
internal map state. The closer code inspection revealed that it's not
required:

    - bpf_object__create_map(): map->inner_map is destroyed after a
      successful call, map->fd is closed if pinning fails.
    - bpf_object__populate_internal_map(): created map elements is
      destroyed upon close(map->fd).
    - init_map_slots(): slots are freed after their initialization.

Signed-off-by: Martynas Pumputis 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20210726152001.34845-1-m@lambda.lt
Signed-off-by: Sasha Levin

libbpf: Fix reuse of pinned map on older kernel

2021-09-18T11:43:36+00:00

[ Upstream commit 97eb31384af943d6b97eb5947262cee4ef25cb87 ]

When loading a BPF program with a pinned map, the loader checks whether
the pinned map can be reused, i.e. their properties match. To derive
such of the pinned map, the loader invokes BPF_OBJ_GET_INFO_BY_FD and
then does the comparison.

Unfortunately, on < 4.12 kernels the BPF_OBJ_GET_INFO_BY_FD is not
available, so loading the program fails with the following error:

	libbpf: failed to get map info for map FD 5: Invalid argument
	libbpf: couldn't reuse pinned map at
		'/sys/fs/bpf/tc/globals/cilium_call_policy': parameter
		mismatch"
	libbpf: map 'cilium_call_policy': error reusing pinned map
	libbpf: map 'cilium_call_policy': failed to create:
		Invalid argument(-22)
	libbpf: failed to load object 'bpf_overlay.o'

To fix this, fallback to derivation of the map properties via
/proc/$PID/fdinfo/$MAP_FD if BPF_OBJ_GET_INFO_BY_FD fails with EINVAL,
which can be used as an indicator that the kernel doesn't support
the latter.

Signed-off-by: Martynas Pumputis 
Signed-off-by: Andrii Nakryiko 
Acked-by: John Fastabend 
Link: https://lore.kernel.org/bpf/20210712125552.58705-1-m@lambda.lt
Signed-off-by: Sasha Levin

libbpf: Re-build libbpf.so when libbpf.map changes

2021-09-15T08:02:23+00:00

[ Upstream commit 61c7aa5020e98ac2fdcf07d07eec1baf2e9f0a08 ]

Ensure libbpf.so is re-built whenever libbpf.map is modified.  Without this,
changes to libbpf.map are not detected and versioned symbols mismatch error
will be reported until `make clean && make` is used, which is a suboptimal
developer experience.

Fixes: 306b267cb3c4 ("libbpf: Verify versioned symbols")
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Daniel Borkmann 
Acked-by: Yonghong Song 
Link: https://lore.kernel.org/bpf/20210815070609.987780-8-andrii@kernel.org
Signed-off-by: Sasha Levin

libbpf: Return non-null error on failures in libbpf_find_prog_btf_id()

2021-09-15T08:02:16+00:00

[ Upstream commit 6d2d73cdd673d493f9f3751188757129b1d23fb7 ]

Variable "err" is initialised to -EINVAL so that this error code is
returned when something goes wrong in libbpf_find_prog_btf_id().
However, a recent change in the function made use of the variable in
such a way that it is set to 0 if retrieving linear information on the
program is successful, and this 0 value remains if we error out on
failures at later stages.

Let's fix this by setting err to -EINVAL later in the function.

Fixes: e9fc3ce99b34 ("libbpf: Streamline error reporting for high-level APIs")
Signed-off-by: Quentin Monnet 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20210729162028.29512-2-quentin@isovalent.com
Signed-off-by: Sasha Levin

libbpf: Fix removal of inner map in bpf_object__create_map

2021-09-15T08:02:12+00:00

[ Upstream commit a21ab4c59e09c2a9994a6e393b7484e3b3f78a99 ]

If creating an outer map of a BTF-defined map-in-map fails (via
bpf_object__create_map()), then the previously created its inner map
won't be destroyed.

Fix this by ensuring that the destroy routines are not bypassed in the
case of a failure.

Fixes: 646f02ffdd49c ("libbpf: Add BTF-defined map-in-map support")
Reported-by: Andrii Nakryiko 
Signed-off-by: Martynas Pumputis 
Signed-off-by: Andrii Nakryiko 
Acked-by: John Fastabend 
Link: https://lore.kernel.org/bpf/20210719173838.423148-2-m@lambda.lt
Signed-off-by: Sasha Levin

libbpf: Fix the possible memory leak on error

2021-09-15T08:02:11+00:00

[ Upstream commit 18353c87e0e0440d4c7c746ed740738bbc1b538e ]

If the strdup() fails then we need to call bpf_object__close(obj) to
avoid a resource leak.

Fixes: 166750bc1dd2 ("libbpf: Support libbpf-provided extern variables")
Signed-off-by: Shuyi Cheng 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/1626180159-112996-3-git-send-email-chengshuyi@linux.alibaba.com
Signed-off-by: Sasha Levin

libbpf: Do not close un-owned FD 0 on errors

2021-08-06T23:39:15+00:00

Before this patch, btf_new() was liable to close an arbitrary FD 0 if
BTF parsing failed. This was because:

* btf->fd was initialized to 0 through the calloc()
* btf__free() (in the `done` label) closed any FDs >= 0
* btf->fd is left at 0 if parsing fails

This issue was discovered on a system using libbpf v0.3 (without
BTF_KIND_FLOAT support) but with a kernel that had BTF_KIND_FLOAT types
in BTF. Thus, parsing fails.

While this patch technically doesn't fix any issues b/c upstream libbpf
has BTF_KIND_FLOAT support, it'll help prevent issues in the future if
more BTF types are added. It also allow the fix to be backported to
older libbpf's.

Fixes: 3289959b97ca ("libbpf: Support BTF loading and raw data output in both endianness")
Signed-off-by: Daniel Xu 
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Daniel Borkmann 
Acked-by: Yonghong Song 
Link: https://lore.kernel.org/bpf/5969bb991adedb03c6ae93e051fd2a00d293cf25.1627513670.git.dxu@dxuuu.xyz

libbpf: Fix probe for BPF_PROG_TYPE_CGROUP_SOCKOPT

2021-08-06T23:38:52+00:00

This patch fixes the probe for BPF_PROG_TYPE_CGROUP_SOCKOPT,
so the probe reports accurate results when used by e.g.
bpftool.

Fixes: 4cdbfb59c44a ("libbpf: support sockopt hooks")
Signed-off-by: Robin Gögge 
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Daniel Borkmann 
Reviewed-by: Quentin Monnet 
Link: https://lore.kernel.org/bpf/20210728225825.2357586-1-r.goegge@gmail.com

libbpf: Restore errno return for functions that were already returning it

2021-07-07T04:13:08+00:00

The update to streamline libbpf error reporting intended to change all
functions to return the errno as a negative return value if
LIBBPF_STRICT_DIRECT_ERRS is set. However, if the flag is *not* set, the
return value changes for the two functions that were already returning a
negative errno unconditionally: bpf_link__unpin() and perf_buffer__poll().

This is a user-visible API change that breaks applications; so let's revert
these two functions back to unconditionally returning a negative errno
value.

Fixes: e9fc3ce99b34 ("libbpf: Streamline error reporting for high-level APIs")
Signed-off-by: Toke Høiland-Jørgensen 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20210706122355.236082-1-toke@redhat.com

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

2021-06-28T22:28:03+00:00

Daniel Borkmann says:

====================
pull-request: bpf-next 2021-06-28

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

We've added 37 non-merge commits during the last 12 day(s) which contain
a total of 56 files changed, 394 insertions(+), 380 deletions(-).

The main changes are:

1) XDP driver RCU cleanups, from Toke Høiland-Jørgensen and Paul E. McKenney.

2) Fix bpf_skb_change_proto() IPv4/v6 GSO handling, from Maciej Żenczykowski.

3) Fix false positive kmemleak report for BPF ringbuf alloc, from Rustam Kovhaev.

4) Fix x86 JIT's extable offset calculation for PROBE_LDX NULL, from Ravi Bangoria.

5) Enable libbpf fallback probing with tracing under RHEL7, from Jonathan Edwards.

6) Clean up x86 JIT to remove unused cnt tracking from EMIT macro, from Jiri Olsa.

7) Netlink cleanups for libbpf to please Coverity, from Kumar Kartikeya Dwivedi.

8) Allow to retrieve ancestor cgroup id in tracing programs, from Namhyung Kim.

9) Fix lirc BPF program query to use user-provided prog_cnt, from Sean Young.

10) Add initial libbpf doc including generated kdoc for its API, from Grant Seltzer.

11) Make xdp_rxq_info_unreg_mem_model() more robust, from Jakub Kicinski.

12) Fix up bpfilter startup log-level to info level, from Gary Lin.
====================

Signed-off-by: David S. Miller