linux-stable.git/tools/bpf, branch v5.5.8

bpf: Print error message for bpftool cgroup show

2020-02-24T07:38:20+00:00

[ Upstream commit 1162f844030ac1ac7321b5e8f6c9badc7a11428f ]

Currently, when bpftool cgroup show  has an error, no error
message is printed. This is confusing because the user may think the
result is empty.

Before the change:

$ bpftool cgroup show /sys/fs/cgroup
ID       AttachType      AttachFlags     Name
$ echo $?
255

After the change:
$ ./bpftool cgroup show /sys/fs/cgroup
Error: can't query bpf programs attached to /sys/fs/cgroup: Operation
not permitted

v2: Rename check_query_cgroup_progs to cgroup_has_attached_progs

Signed-off-by: Hechao Li 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20191224011742.3714301-1-hechaol@fb.com
Signed-off-by: Sasha Levin

bpftool: Don't crash on missing xlated program instructions

2020-02-14T21:52:59+00:00

commit d95f1e8b462c4372ac409886070bb8719d8a4d3a upstream.

Turns out the xlated program instructions can also be missing if
kptr_restrict sysctl is set. This means that the previous fix to check the
jited_prog_insns pointer was insufficient; add another check of the
xlated_prog_insns pointer as well.

Fixes: 5b79bcdf0362 ("bpftool: Don't crash on missing jited insns or ksyms")
Fixes: cae73f233923 ("bpftool: use bpf_program__get_prog_info_linear() in prog.c:do_dump()")
Signed-off-by: Toke Høiland-Jørgensen 
Signed-off-by: Daniel Borkmann 
Reviewed-by: Quentin Monnet 
Link: https://lore.kernel.org/bpf/20200206102906.112551-1-toke@redhat.com
Signed-off-by: Greg Kroah-Hartman

bpftool: Fix printing incorrect pointer in btf_dump_ptr

2020-01-12T03:08:21+00:00

For plain text output, it incorrectly prints the pointer value
"void *data".  The "void *data" is actually pointing to memory that
contains a bpf-map's value.  The intention is to print the content of
the bpf-map's value instead of printing the pointer pointing to the
bpf-map's value.

In this case, a member of the bpf-map's value is a pointer type.
Thus, it should print the "*(void **)data".

Fixes: 22c349e8db89 ("tools: bpftool: fix format strings and arguments for jsonw_printf()")
Signed-off-by: Martin KaFai Lau 
Signed-off-by: Alexei Starovoitov 
Reviewed-by: Quentin Monnet 
Link: https://lore.kernel.org/bpf/20200110231644.3484151-1-kafai@fb.com

bpftool: Don't crash on missing jited insns or ksyms

2019-12-11T12:57:26+00:00

When the kptr_restrict sysctl is set, the kernel can fail to return
jited_ksyms or jited_prog_insns, but still have positive values in
nr_jited_ksyms and jited_prog_len. This causes bpftool to crash when
trying to dump the program because it only checks the len fields not
the actual pointers to the instructions and ksyms.

Fix this by adding the missing checks.

Fixes: 71bb428fe2c1 ("tools: bpf: add bpftool")
Fixes: f84192ee00b7 ("tools: bpftool: resolve calls without using imm field")
Signed-off-by: Toke Høiland-Jørgensen 
Signed-off-by: Daniel Borkmann 
Acked-by: Martin KaFai Lau 
Link: https://lore.kernel.org/bpf/20191210181412.151226-1-toke@redhat.com

tools, bpf: Fix build for 'make -s tools/bpf O='

2019-11-25T00:58:45+00:00

Building selftests with 'make TARGETS=bpf kselftest' was fixed in commit
55d554f5d140 ("tools: bpf: Use !building_out_of_srctree to determine
srctree"). However, by updating $(srctree) in tools/bpf/Makefile for
in-tree builds only, we leave out the case where we pass an output
directory to build BPF tools, but $(srctree) is not set. This
typically happens for:

    $ make -s tools/bpf O=/tmp/foo
    Makefile:40: /tools/build/Makefile.feature: No such file or directory

Fix it by updating $(srctree) in the Makefile not only for out-of-tree
builds, but also if $(srctree) is empty.

Detected with test_bpftool_build.sh.

Fixes: 55d554f5d140 ("tools: bpf: Use !building_out_of_srctree to determine srctree")
Signed-off-by: Quentin Monnet 
Signed-off-by: Daniel Borkmann 
Acked-by: Jakub Kicinski 
Link: https://lore.kernel.org/bpf/20191119105626.21453-1-quentin.monnet@netronome.com

tools, bpftool: Fix warning on ignored return value for 'read'

2019-11-25T00:58:44+00:00

When building bpftool, a warning was introduced by commit a94364603610
("bpftool: Allow to read btf as raw data"), because the return value
from a call to 'read()' is ignored. Let's address it.

Signed-off-by: Quentin Monnet 
Signed-off-by: Daniel Borkmann 
Reviewed-by: Jakub Kicinski 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20191119111706.22440-1-quentin.monnet@netronome.com

tools, bpf_asm: Warn when jumps are out of range

2019-11-07T15:01:34+00:00

When compiling larger programs with bpf_asm, it's possible to
accidentally exceed jt/jf range, in which case it won't complain, but
rather silently emit a truncated offset, leading to a "happy debugging"
situation.

Add a warning to help detecting such issues. It could be made an error
instead, but this might break compilation of existing code (which might
be working by accident).

Signed-off-by: Ilya Leoshkevich 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20191107100349.88976-1-iii@linux.ibm.com

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

2019-10-27T05:57:27+00:00

Daniel Borkmann says:

====================
pull-request: bpf-next 2019-10-27

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

We've added 52 non-merge commits during the last 11 day(s) which contain
a total of 65 files changed, 2604 insertions(+), 1100 deletions(-).

The main changes are:

 1) Revolutionize BPF tracing by using in-kernel BTF to type check BPF
    assembly code. The work here teaches BPF verifier to recognize
    kfree_skb()'s first argument as 'struct sk_buff *' in tracepoints
    such that verifier allows direct use of bpf_skb_event_output() helper
    used in tc BPF et al (w/o probing memory access) that dumps skb data
    into perf ring buffer. Also add direct loads to probe memory in order
    to speed up/replace bpf_probe_read() calls, from Alexei Starovoitov.

 2) Big batch of changes to improve libbpf and BPF kselftests. Besides
    others: generalization of libbpf's CO-RE relocation support to now
    also include field existence relocations, revamp the BPF kselftest
    Makefile to add test runner concept allowing to exercise various
    ways to build BPF programs, and teach bpf_object__open() and friends
    to automatically derive BPF program type/expected attach type from
    section names to ease their use, from Andrii Nakryiko.

 3) Fix deadlock in stackmap's build-id lookup on rq_lock(), from Song Liu.

 4) Allow to read BTF as raw data from bpftool. Most notable use case
    is to dump /sys/kernel/btf/vmlinux through this, from Jiri Olsa.

 5) Use bpf_redirect_map() helper in libbpf's AF_XDP helper prog which
    manages to improve "rx_drop" performance by ~4%., from Björn Töpel.

 6) Fix to restore the flow dissector after reattach BPF test and also
    fix error handling in bpf_helper_defs.h generation, from Jakub Sitnicki.

 7) Improve verifier's BTF ctx access for use outside of raw_tp, from
    Martin KaFai Lau.

 8) Improve documentation for AF_XDP with new sections and to reflect
    latest features, from Magnus Karlsson.

 9) Add back 'version' section parsing to libbpf for old kernels, from
    John Fastabend.

10) Fix strncat bounds error in libbpf's libbpf_prog_type_by_name(),
    from KP Singh.

11) Turn on -mattr=+alu32 in LLVM by default for BPF kselftests in order
    to improve insn coverage for built BPF progs, from Yonghong Song.

12) Misc minor cleanups and fixes, from various others.
====================

Signed-off-by: David S. Miller

bpftool: Allow to read btf as raw data

2019-10-25T21:34:47+00:00

The bpftool interface stays the same, but now it's possible
to run it over BTF raw data, like:

  $ bpftool btf dump file /sys/kernel/btf/vmlinux
  [1] INT '(anon)' size=4 bits_offset=0 nr_bits=32 encoding=(none)
  [2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none)
  [3] CONST '(anon)' type_id=2

Signed-off-by: Jiri Olsa 
Signed-off-by: Daniel Borkmann 
Acked-by: Andrii Nakryiko 
Acked-by: Jakub Kicinski 
Link: https://lore.kernel.org/bpf/20191024133025.10691-1-jolsa@kernel.org

libbpf: Make DECLARE_LIBBPF_OPTS macro strictly a variable declaration

2019-10-22T19:35:03+00:00

LIBBPF_OPTS is implemented as a mix of field declaration and memset
+ assignment. This makes it neither variable declaration nor purely
statements, which is a problem, because you can't mix it with either
other variable declarations nor other function statements, because C90
compiler mode emits warning on mixing all that together.

This patch changes LIBBPF_OPTS into a strictly declaration of variable
and solves this problem, as can be seen in case of bpftool, which
previously would emit compiler warning, if done this way (LIBBPF_OPTS as
part of function variables declaration block).

This patch also renames LIBBPF_OPTS into DECLARE_LIBBPF_OPTS to follow
kernel convention for similar macros more closely.

v1->v2:
- rename LIBBPF_OPTS into DECLARE_LIBBPF_OPTS (Jakub Sitnicki).

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Daniel Borkmann 
Acked-by: Toke Høiland-Jørgensen 
Link: https://lore.kernel.org/bpf/20191022172100.3281465-1-andriin@fb.com