When bpftool is linked against libcap, the library runs a "constructor"
function to compute the number of capabilities of the running kernel
[0], at the beginning of the execution of the program. As part of this,
it performs multiple calls to prctl(). Some of these may fail, and set
errno to a non-zero value:

    # strace -e prctl ./bpftool version
    prctl(PR_CAPBSET_READ, CAP_MAC_OVERRIDE) = 1
    prctl(PR_CAPBSET_READ, 0x30 /* CAP_??? */) = -1 EINVAL (Invalid argument)
    prctl(PR_CAPBSET_READ, CAP_CHECKPOINT_RESTORE) = 1
    prctl(PR_CAPBSET_READ, 0x2c /* CAP_??? */) = -1 EINVAL (Invalid argument)
    prctl(PR_CAPBSET_READ, 0x2a /* CAP_??? */) = -1 EINVAL (Invalid argument)
    prctl(PR_CAPBSET_READ, 0x29 /* CAP_??? */) = -1 EINVAL (Invalid argument)
    ** fprintf added at the top of main(): we have errno == 1
    ./bpftool v7.0.0
    using libbpf v1.0
    features: libbfd, libbpf_strict, skeletons
    +++ exited with 0 +++

This has been addressed in libcap 2.63 [1], but until this version is
available everywhere, we can fix it on bpftool side.

Let's clean errno at the beginning of the main() function, to make sure
that these checks do not interfere with the batch mode, where we error
out if errno is set after a bpftool command.

  [0] https://git.kernel.org/pub/scm/libs/libcap/libcap.git/tree/libcap/cap_alloc.c?h=libcap-2.65#n20
  [1] https://git.kernel.org/pub/scm/libs/libcap/libcap.git/commit/?id=f25a1b7e69f7b33e6afb58b3e38f3450b7d2d9a0Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220815162205.45043-1-quentin@isovalent.com

Adding or removing room space _below_ layers 2 or 3, as the description
mentions, is ambiguous. This was written with a mental image of the
packet with layer 2 at the top, layer 3 under it, and so on. But it has
led users to believe that it was on lower layers (before the beginning
of the L2 and L3 headers respectively).

Let's make it more explicit, and specify between which layers the room
space is adjusted.
Reported-by: Rumen Telbizov <rumen.telbizov@menlosecurity.com>
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220812153727.224500-3-quentin@isovalent.com

This is the wrong library name: libcap, not libpcap.
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220812153727.224500-1-quentin@isovalent.com

The bpftool self-created maps can appear in final map show output due to
deferred removal in kernel. These maps don't have a name, which would make
users confused about where it comes from.

With a libbpf_ prefix name, users could know who created these maps.
It also could make some tests (like test_offload.py, which skip base maps
without names as a workaround) filter them out.

Kernel adds bpf prog/map name support in the same merge
commit fadad670 ("Merge branch 'bpf-extend-info'"). So we can also use
kernel_supports(NULL, FEAT_PROG_NAME) to check if kernel supports map name.

As discussed [1], Let's make bpf_map_create accept non-null
name string, and silently ignore the name if kernel doesn't support.

  [1] https://lore.kernel.org/bpf/CAEf4BzYL1TQwo1231s83pjTdFPk9XWWhfZC5=KzkU-VO0k=0Ug@mail.gmail.com/Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220811034020.529685-1-liuhangbin@gmail.com

Let's use the generic helper bpf_map_area_alloc() instead of the
open-coded kzalloc helpers in bpf maps creation path.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20220810151840.16394-5-laoar.shao@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Some of the bpf maps are created with __GFP_NOWARN, i.e. arraymap,
bloom_filter, bpf_local_storage, bpf_struct_ops, lpm_trie,
queue_stack_maps, reuseport_array, stackmap and xskmap, while others are
created without __GFP_NOWARN, i.e. cpumap, devmap, hashtab,
local_storage, offload, ringbuf and sock_map. But there are not key
differences between the creation of these maps. So let make this
allocation flag consistent in all bpf maps creation. Then we can use a
generic helper to alloc all bpf maps.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20220810151840.16394-4-laoar.shao@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

bpf_map_area_alloc() should be paired with bpf_map_area_free().
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20220810151840.16394-3-laoar.shao@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

__GFP_ZERO will clear the memory, so we don't need to memset it.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20220810151840.16394-2-laoar.shao@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

As suggested in [0], make sure that libbpf_print saves and restored
errno and as such guaranteed that no matter what actual print callback
user installs, macros like pr_warn/pr_info/pr_debug are completely
transparent as far as errno goes.

While libbpf code is pretty careful about not clobbering important errno
values accidentally with pr_warn(), it's a trivial change to make sure
that pr_warn can be used anywhere without a risk of clobbering errno.

No functional changes, just future proofing.

  [0] https://github.com/libbpf/libbpf/pull/536Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Daniel Müller <deso@posteo.net>
Link: https://lore.kernel.org/r/20220810183425.1998735-1-andrii@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Artem Savkov says:

====================

eBPF is often used for kernel debugging, and one of the widely used and
powerful debugging techniques is post-mortem debugging with a full memory dump.
Triggering a panic at exactly the right moment allows the user to get such a
dump and thus a better view at the system's state. Right now the only way to
do this in BPF is to signal userspace to trigger kexec/panic. This is
suboptimal as going through userspace requires context changes and adds
significant delays taking system further away from "the right moment". On a
single-cpu system the situation is even worse because BPF program won't even be
able to block the thread of interest.

This patchset tries to solve this problem by allowing properly marked tracing
bpf programs to call crash_kexec() kernel function. The only requirement for
now to run programs calling crash_kexec() or other destructive kfuncs is
CAP_SYS_BOOT capability. When signature checking for bpf programs is available
it is possible that stricter rules will be applied to programs utilizing
destructive kfuncs.

Changes in v5:
 - documentation numbering fixed
 - no more warning on failed kfunc registration

Changes in v4:
 - added description for KF_DESTRUCTIVE flag to documentation

Changes in v3:
 - moved kfunc set registration to kernel/bpf/helpers.c

Changes in v2:
 - BPF_PROG_LOAD flag dropped as it doesn't fully achieve it's aim of
   preventing accidental execution of destructive bpf programs
 - selftest moved to the end of patchset
 - switched to kfunc destructive flag instead of a separate set

Changes from RFC:
 - sysctl knob dropped
 - using crash_kexec() instead of panic()
 - using kfuncs instead of adding a new helper
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Add a test checking that programs calling destructive kfuncs can only do
so if they have CAP_SYS_BOOT capabilities.
Signed-off-by: Artem Savkov <asavkov@redhat.com>
Link: https://lore.kernel.org/r/20220810065905.475418-4-asavkov@redhat.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Allow properly marked bpf programs to call crash_kexec().
Signed-off-by: Artem Savkov <asavkov@redhat.com>
Link: https://lore.kernel.org/r/20220810065905.475418-3-asavkov@redhat.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Add KF_DESTRUCTIVE flag for destructive functions. Functions with this
flag set will require CAP_SYS_BOOT capabilities.
Signed-off-by: Artem Savkov <asavkov@redhat.com>
Link: https://lore.kernel.org/r/20220810065905.475418-2-asavkov@redhat.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Poll test case was not testing all the functionality of the poll feature
in the test suite. This patch updates the poll test case which contains 2
test cases to test the RX and the TX poll functionality and additional 2
more test cases to check the timeout feature of the poll event.

Poll test suite has 4 test cases:

1. TEST_TYPE_RX_POLL: Check if RX path POLLIN function works as expect.
   TX path can use any method to send the traffic.

2. TEST_TYPE_TX_POLL: Check if TX path POLLOUT function works as expect.
   RX path can use any method to receive the traffic.

3. TEST_TYPE_POLL_RXQ_EMPTY: Call poll function with parameter POLLIN on
   empty RX queue will cause timeout. If timeout then test case passes.

4. TEST_TYPE_POLL_TXQ_FULL: When TX queue is filled and packets are not
   cleaned by the kernel then if we invoke the poll function with POLLOUT
   it should trigger timeout.
Signed-off-by: Shibin Koikkara Reeny <shibin.koikkara.reeny@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Link: https://lore.kernel.org/bpf/20220803144354.98122-1-shibin.koikkara.reeny@intel.com

Add an additional test, "data_slice_use_after_release2", for ensuring
that data slices are correctly invalidated by the verifier after the
dynptr whose ref obj id they track is released. In particular, this
tests data slice invalidation for dynptrs located at a non-zero offset
from the frame pointer.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/r/20220809214055.4050604-2-joannelkoong@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

When a data slice is obtained from a dynptr (through the bpf_dynptr_data API),
the ref obj id of the dynptr must be found and then associated with the data
slice.

The ref obj id of the dynptr must be found *before* the caller saved regs are
reset. Without this fix, the ref obj id tracking is not correct for
dynptrs that are at an offset from the frame pointer.

Please also note that the data slice's ref obj id must be assigned after the
ret types are parsed, since RET_PTR_TO_ALLOC_MEM-type return regs get
zero-marked.

Fixes: 34d4ef57 ("bpf: Add dynptr data slices")
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20220809214055.4050604-1-joannelkoong@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Before, you could see the following errors:

  $ ./vmtest.sh -j
  ./vmtest.sh: option requires an argument -- j
  ./vmtest.sh: line 357: OPTARG: unbound variable

  $ ./vmtest.sh -z
  ./vmtest.sh: illegal option -- z
  ./vmtest.sh: line 357: OPTARG: unbound variable

Fix by adding ':' as first character of optstring. Reason is that getopts
requires ':' as the first character for OPTARG to be set in the `?` and `:`
error cases.

Note that the ':' as the first character of the optstring switches getopts
to silent mode. The desire to run in this mode seems to have been there all
along, as the script takes care of reporting errors.
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Müller <deso@posteo.net>
Link: https://lore.kernel.org/bpf/0f93b56198328b6b4da7b4cf4662d05c3edb5fd2.1660064925.git.dxu@dxuuu.xyz

Set the exit trap only after argument parsing is done. This way argument
parse failure or `-h` will not require sudo.

Reasoning is that it's confusing that a help message would require root
access.
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Müller <deso@posteo.net>
Link: https://lore.kernel.org/bpf/6a802aa37758e5a7e6aa5de294634f5518005e2b.1660064925.git.dxu@dxuuu.xyz

Currently in funciton __get_type_size(), the corresponding
btf_type is returned only in invalid cases. Let us always
return btf_type regardless of valid or invalid cases.
Such a new functionality will be used in subsequent patches.
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220807175116.4179242-1-yhs@fb.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Kurt Kanzenbach says:

====================

Hi,

add a BPF-helper for accessing CLOCK_TAI. Use cases for such a BPF helper
include functionalities such as Tx launch time (e.g. ETF and TAPRIO Qdiscs),
timestamping and policing.

Patch #1 - Introduce BPF helper
Patch #2 - Add test case (skb based)

Changes since v1:

 * Update changelog (Alexei Starovoitov)
 * Add test case (Alexei Starovoitov, Andrii Nakryiko)
 * Add missing function prototype (netdev ci)

Previous versions:

 * v1: https://lore.kernel.org/r/20220606103734.92423-1-kurt@linutronix.de/

Jesper Dangaard Brouer (1):
  bpf: Add BPF-helper for accessing CLOCK_TAI
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Add BPF-helper test case for CLOCK_TAI access. The added test verifies that:

 * Timestamps are generated
 * Timestamps are moving forward
 * Timestamps are reasonable
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Link: https://lore.kernel.org/r/20220809060803.5773-3-kurt@linutronix.deSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Commit 3dc6ffae ("timekeeping: Introduce fast accessor to clock tai")
introduced a fast and NMI-safe accessor for CLOCK_TAI. Especially in time
sensitive networks (TSN), where all nodes are synchronized by Precision Time
Protocol (PTP), it's helpful to have the possibility to generate timestamps
based on CLOCK_TAI instead of CLOCK_MONOTONIC. With a BPF helper for TAI in
place, it becomes very convenient to correlate activity across different
machines in the network.

Use cases for such a BPF helper include functionalities such as Tx launch
time (e.g. ETF and TAPRIO Qdiscs) and timestamping.

Note: CLOCK_TAI is nothing new per se, only the NMI-safe variant of it is.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
[Kurt: Wrote changelog and renamed helper]
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Link: https://lore.kernel.org/r/20220809060803.5773-2-kurt@linutronix.deSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Discussion around a recently-submitted patch provided historical
context for check_refcount_ok [0]. Specifically, the function and its
helpers - may_be_acquire_function and arg_type_may_be_refcounted -
predate the OBJ_RELEASE type flag and the addition of many more helpers
with acquire/release semantics.

The purpose of check_refcount_ok is to ensure:
  1) Helper doesn't have multiple uses of return reg's ref_obj_id
  2) Helper with release semantics only has one arg needing to be
  released, since that's tracked using meta->ref_obj_id

With current verifier, it's safe to remove check_refcount_ok and its
helpers. Since addition of OBJ_RELEASE type flag, case 2) has been
handled by the arg_type_is_release check in check_func_arg. To ensure
case 1) won't result in verifier silently prioritizing one use of
ref_obj_id, this patch adds a helper_multiple_ref_obj_use check which
fails loudly if a helper passes > 1 test for use of ref_obj_id.

  [0]: lore.kernel.org/bpf/20220713234529.4154673-1-davemarchevsky@fb.com
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Joanne Koong <joannelkoong@gmail.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220808171559.3251090-1-davemarchevsky@fb.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

The current ifdefry for code shared by the BPF and ctnetlink side looks
ugly. As per Pablo's request, simplify this by unconditionally compiling
in the code. This can be revisited when the shared code between the two
grows further.
Suggested-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220725085130.11553-1-memxor@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

In bpf_seq_read, seq->op->next() could return an ERR and jump to
the label stop. However, the existing code in stop does not handle
the case when p (returned from next()) is an ERR. Adds the handling
of ERR of p by converting p into an error and jumping to done.

Because all the current implementations do not have a case that
returns ERR from next(), so this patch doesn't have behavior changes
right now.
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Hao Luo <haoluo@google.com>
Link: https://lore.kernel.org/r/20220805214821.1058337-4-haoluo@google.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

cgroup_get_from_file() currently fails with -EBADF if called on cgroup
v1. However, the current implementation works on cgroup v1 as well, so
the restriction is unnecessary.

This enabled cgroup_get_from_fd() to work on cgroup v1, which would be
the only thing stopping bpf cgroup_iter from supporting cgroup v1.
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Hao Luo <haoluo@google.com>
Link: https://lore.kernel.org/r/20220805214821.1058337-3-haoluo@google.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

This allows to declare a kfunc as sleepable and prevents its use in
a non sleepable program.
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Co-developed-by: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Hao Luo <haoluo@google.com>
Link: https://lore.kernel.org/r/20220805214821.1058337-2-haoluo@google.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Most tools which use bpf_get_stack or bpf_get_stackid symbolicate the
stack - meaning the stack of addresses in the target process' address
space is transformed into meaningful symbol names. The
BPF_F_USER_BUILD_ID flag eases this process by finding the build_id of
the file-backed vma which the address falls in and translating the
address to an offset within the backing file.

To be more specific, the offset is a "file offset" from the beginning of
the backing file. The symbols in ET_DYN ELF objects have a st_value
which is also described as an "offset" - but an offset in the process
address space, relative to the base address of the object.

It's necessary to translate between the "file offset" and "virtual
address offset" during symbolication before they can be directly
compared. Failure to do so can lead to confusing bugs, so this patch
clarifies language in the documentation in an attempt to keep this from
happening.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220808164723.3107500-1-davemarchevsky@fb.com

Currently, resolve_full_path() requires executable permission for both
programs and shared libraries. This causes failures on distos like Debian
since the shared libraries are not installed executable and Linux is not
requiring shared libraries to have executable permissions. Let's remove
executable permission check for shared libraries.
Reported-by: Goro Fuji <goro@fastly.com>
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220806102021.3867130-1-hengqi.chen@gmail.com

This patch cleans up a few things in the verifier:

  * type_is_pkt_pointer():
    Future work (skb + xdp dynptrs [0]) will be using the reg type
    PTR_TO_PACKET | PTR_MAYBE_NULL. type_is_pkt_pointer() should return
    true for any type whose base type is PTR_TO_PACKET, regardless of
    flags attached to it.

  * reg_type_may_be_refcounted_or_null():
    Get the base type at the start of the function to avoid
    having to recompute it / improve readability

  * check_func_proto(): remove unnecessary 'meta' arg

  * check_helper_call():
    Use switch casing on the base type of return value instead of
    nested ifs on the full type

There are no functional behavior changes.

  [0] https://lore.kernel.org/bpf/20220726184706.954822-1-joannelkoong@gmail.com/Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20220802214638.3643235-1-joannelkoong@gmail.com

Add explicit error message if BPF object file is still using legacy BPF
map definitions in SEC("maps"). Before this change, if BPF object file
is still using legacy map definition user will see a bit confusing:

  libbpf: elf: skipping unrecognized data section(4) maps
  libbpf: prog 'handler': bad map relo against 'server_map' in section 'maps'

Now libbpf will be explicit about rejecting "maps" ELF section:

  libbpf: elf: legacy map definitions in 'maps' section are not supported by libbpf v1.0+
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220803214202.23750-1-andrii@kernel.org

This patch cleans up a few things:

  * dynptr_fail.c:
    There is no sys_nanosleep tracepoint. dynptr_fail only tests
    that the prog load fails, so just SEC("?raw_tp") suffices here.

  * test_bpf_cookie:
    There is no sys_nanosleep kprobe. The prog is loaded in
    userspace through bpf_program__attach_kprobe_opts passing in
    SYS_NANOSLEEP_KPROBE_NAME, so just SEC("k{ret}probe") suffices here.

  * test_helper_restricted:
    There is no sys_nanosleep kprobe. test_helper_restricted only tests
    that the prog load fails, so just SEC("?kprobe")( suffices here.

There are no functional changes.
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220805171405.2272103-1-joannelkoong@gmail.com

GCC expects the always_inline attribute to only be set on inline
functions, as such we should make all functions with this attribute
use the __always_inline macro which makes the function inline and
sets the attribute.

Fixes errors like:
/home/buildroot/bpf-next/tools/testing/selftests/bpf/tools/include/bpf/bpf_tracing.h:439:1: error: ‘always_inline’ function might not be inlinable [-Werror=attributes]
  439 | ____##name(unsigned long long *ctx, ##args)
      | ^~~~
Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20220803151403.793024-1-james.hilliard1@gmail.com

bpftool was limiting the length of names to BPF_OBJ_NAME_LEN in prog_parse
fds.

Since commit b662000a ("bpftool: Adding support for BTF program names")
we can get the full program name from BTF.

This patch removes the restriction of name length when running `bpftool
prog show name ${name}`.

Test:
Tested against some internal program names that were longer than
`BPF_OBJ_NAME_LEN`, here a redacted example of what was ran to test.

    # previous behaviour
    $ sudo bpftool prog show name some_long_program_name
    Error: can't parse name
    # with the patch
    $ sudo ./bpftool prog show name some_long_program_name
    123456789: tracing  name some_long_program_name  tag taghexa  gpl ....
    ...
    ...
    ...
    # too long
    sudo ./bpftool prog show name $(python3 -c 'print("A"*128)')
    Error: can't parse name
    # not too long but no match
    $ sudo ./bpftool prog show name $(python3 -c 'print("A"*127)')
Signed-off-by: Manu Bretelle <chantr4@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20220801132409.4147849-1-chantr4@gmail.com

GCC-11 warns about the possibly unitialized err variable in
probe_map_create:

libbpf_probes.c: In function 'probe_map_create':
libbpf_probes.c:361:38: error: 'err' may be used uninitialized in this function [-Werror=maybe-uninitialized]
  361 |                 return fd < 0 && err == exp_err ? 1 : 0;
      |                                  ~~~~^~~~~~~~~~

Fixes: 878d8def ("libbpf: Rework feature-probing APIs")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20220801025109.1206633-1-f.fainelli@gmail.com

The GNU assembler generates an empty .bss section. This is a well
established behavior in GAS that happens in all supported targets.

The LLVM assembler doesn't generate an empty .bss section.

bpftool chokes on the empty .bss section.

Additionally in bpf_object__elf_collect the sec_desc->data is not
initialized when a section is not recognized. In this case, this
happens with .comment.

So we must check that sec_desc->data is initialized before checking
if the size is 0.
Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20220731232649.4668-1-james.hilliard1@gmail.com

Pull networking changes from Paolo Abeni:
 "Core:

   - Refactor the forward memory allocation to better cope with memory
     pressure with many open sockets, moving from a per socket cache to
     a per-CPU one

   - Replace rwlocks with RCU for better fairness in ping, raw sockets
     and IP multicast router.

   - Network-side support for IO uring zero-copy send.

   - A few skb drop reason improvements, including codegen the source
     file with string mapping instead of using macro magic.

   - Rename reference tracking helpers to a more consistent netdev_*
     schema.

   - Adapt u64_stats_t type to address load/store tearing issues.

   - Refine debug helper usage to reduce the log noise caused by bots.

  BPF:

   - Improve socket map performance, avoiding skb cloning on read
     operation.

   - Add support for 64 bits enum, to match types exposed by kernel.

   - Introduce support for sleepable uprobes program.

   - Introduce support for enum textual representation in libbpf.

   - New helpers to implement synproxy with eBPF/XDP.

   - Improve loop performances, inlining indirect calls when possible.

   - Removed all the deprecated libbpf APIs.

   - Implement new eBPF-based LSM flavor.

   - Add type match support, which allow accurate queries to the eBPF
     used types.

   - A few TCP congetsion control framework usability improvements.

   - Add new infrastructure to manipulate CT entries via eBPF programs.

   - Allow for livepatch (KLP) and BPF trampolines to attach to the same
     kernel function.

  Protocols:

   - Introduce per network namespace lookup tables for unix sockets,
     increasing scalability and reducing contention.

   - Preparation work for Wi-Fi 7 Multi-Link Operation (MLO) support.

   - Add support to forciby close TIME_WAIT TCP sockets via user-space
     tools.

   - Significant performance improvement for the TLS 1.3 receive path,
     both for zero-copy and not-zero-copy.

   - Support for changing the initial MTPCP subflow priority/backup
     status

   - Introduce virtually contingus buffers for sockets over RDMA, to
     cope better with memory pressure.

   - Extend CAN ethtool support with timestamping capabilities

   - Refactor CAN build infrastructure to allow building only the needed
     features.

  Driver API:

   - Remove devlink mutex to allow parallel commands on multiple links.

   - Add support for pause stats in distributed switch.

   - Implement devlink helpers to query and flash line cards.

   - New helper for phy mode to register conversion.

  New hardware / drivers:

   - Ethernet DSA driver for the rockchip mt7531 on BPI-R2 Pro.

   - Ethernet DSA driver for the Renesas RZ/N1 A5PSW switch.

   - Ethernet DSA driver for the Microchip LAN937x switch.

   - Ethernet PHY driver for the Aquantia AQR113C EPHY.

   - CAN driver for the OBD-II ELM327 interface.

   - CAN driver for RZ/N1 SJA1000 CAN controller.

   - Bluetooth: Infineon CYW55572 Wi-Fi plus Bluetooth combo device.

  Drivers:

   - Intel Ethernet NICs:
      - i40e: add support for vlan pruning
      - i40e: add support for XDP framented packets
      - ice: improved vlan offload support
      - ice: add support for PPPoE offload

   - Mellanox Ethernet (mlx5)
      - refactor packet steering offload for performance and scalability
      - extend support for TC offload
      - refactor devlink code to clean-up the locking schema
      - support stacked vlans for bridge offloads
      - use TLS objects pool to improve connection rate

   - Netronome Ethernet NICs (nfp):
      - extend support for IPv6 fields mangling offload
      - add support for vepa mode in HW bridge
      - better support for virtio data path acceleration (VDPA)
      - enable TSO by default

   - Microsoft vNIC driver (mana)
      - add support for XDP redirect

   - Others Ethernet drivers:
      - bonding: add per-port priority support
      - microchip lan743x: extend phy support
      - Fungible funeth: support UDP segmentation offload and XDP xmit
      - Solarflare EF100: add support for virtual function representors
      - MediaTek SoC: add XDP support

   - Mellanox Ethernet/IB switch (mlxsw):
      - dropped support for unreleased H/W (XM router).
      - improved stats accuracy
      - unified bridge model coversion improving scalability (parts 1-6)
      - support for PTP in Spectrum-2 asics

   - Broadcom PHYs
      - add PTP support for BCM54210E
      - add support for the BCM53128 internal PHY

   - Marvell Ethernet switches (prestera):
      - implement support for multicast forwarding offload

   - Embedded Ethernet switches:
      - refactor OcteonTx MAC filter for better scalability
      - improve TC H/W offload for the Felix driver
      - refactor the Microchip ksz8 and ksz9477 drivers to share the
        probe code (parts 1, 2), add support for phylink mac
        configuration

   - Other WiFi:
      - Microchip wilc1000: diable WEP support and enable WPA3
      - Atheros ath10k: encapsulation offload support

  Old code removal:

   - Neterion vxge ethernet driver: this is untouched since more than 10 years"

* tag 'net-next-6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1890 commits)
  doc: sfp-phylink: Fix a broken reference
  wireguard: selftests: support UML
  wireguard: allowedips: don't corrupt stack when detecting overflow
  wireguard: selftests: update config fragments
  wireguard: ratelimiter: use hrtimer in selftest
  net/mlx5e: xsk: Discard unaligned XSK frames on striding RQ
  net: usb: ax88179_178a: Bind only to vendor-specific interface
  selftests: net: fix IOAM test skip return code
  net: usb: make USB_RTL8153_ECM non user configurable
  net: marvell: prestera: remove reduntant code
  octeontx2-pf: Reduce minimum mtu size to 60
  net: devlink: Fix missing mutex_unlock() call
  net/tls: Remove redundant workqueue flush before destroy
  net: txgbe: Fix an error handling path in txgbe_probe()
  net: dsa: Fix spelling mistakes and cleanup code
  Documentation: devlink: add add devlink-selftests to the table of contents
  dccp: put dccp_qpolicy_full() and dccp_qpolicy_push() in the same lock
  net: ionic: fix error check for vlan flags in ionic_set_nic_features()
  net: ice: fix error NETIF_F_HW_VLAN_CTAG_FILTER check in ice_vsi_sync_fltr()
  nfp: flower: add support for tunnel offload without key ID
  ...

Pull ATA updates from Damien Le Moal:

 - Some code refactoring for the pata_hpt37x and pata_hpt3x2n drivers,
   from Sergei.

 - Several patches to cleanup in libata-core, libata-scsi and libata-eh
   code: fixes arguments and variables types, change some functions
   declaration to static and fix for a typo in a comment. From Sergey
   and Xiang.

 - Fix a compilation warning in the pata_macio driver, from me.

 - A fix for the expected number of resources in the sata_mv driver fix,
   from Andrew.

* tag 'ata-5.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/libata:
  ata: sata_mv: Fixes expected number of resources now IRQs are gone
  ata: libata-scsi: fix result type of ata_ioc32()
  ata: pata_macio: Fix compilation warning
  ata: libata-eh: fix sloppy result type of ata_internal_cmd_timeout()
  ata: libata-core: fix sloppy parameter type in ata_exec_internal[_sg]()
  ata: make ata_port::fastdrain_cnt *unsigned int*
  ata: libata-eh: fix sloppy result type of ata_eh_nr_in_flight()
  ata: libata-core: make ata_exec_internal_sg() *static*
  ata: make transfer mode masks *unsigned int*
  ata: libata-core: get rid of *else* branches in ata_id_n_sectors()
  ata: libata-core: fix sloppy typing in ata_id_n_sectors()
  ata: pata_hpt3x2n: pass base DPLL frequency to hpt3x2n_pci_clock()
  ata: pata_hpt37x: merge hpt374_read_freq() to hpt37x_pci_clock()
  ata: pata_hpt37x: factor out hpt37x_pci_clock()
  ata: pata_hpt37x: move claculating PCI clock from hpt37x_clock_slot()
  ata: libata: Fix syntax errors in comments

Pull zonefs update from Damien Le Moal:
 "A single change for this cycle to simplify handling of the memory page
  used as super block buffer during mount (from Fabio)"

* tag 'zonefs-5.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/zonefs:
  zonefs: Call page_address() on page acquired with GFP_KERNEL flag

Pull iomap updates from Darrick Wong:
 "The most notable change in this first batch is that we no longer
  schedule pages beyond i_size for writeback, preferring instead to let
  truncate deal with those pages.

  Next week, there may be a second pull request to remove
  iomap_writepage from the other two filesystems (gfs2/zonefs) that use
  iomap for buffered IO. This follows in the same vein as the recent
  removal of writepage from XFS, since it hasn't been triggered in a few
  years; it does nothing during direct reclaim; and as far as the people
  who examined the patchset can tell, it's moving the codebase in the
  right direction.

  However, as it was a late addition to for-next, I'm holding off on
  that section for another week of testing to see if anyone can come up
  with a solid reason for holding off in the meantime.

  Summary:

   - Skip writeback for pages that are completely beyond EOF

   - Minor code cleanups"

* tag 'iomap-5.20-merge-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  dax: set did_zero to true when zeroing successfully
  iomap: set did_zero to true when zeroing successfully
  iomap: skip pages past eof in iomap_do_writepage()