kernel/git/next/linux-next.git/tools/bpf, branch akpm

bpftool: Do not check return value from libbpf_set_strict_mode()

2022-06-14T20:18:56+00:00

The function always returns 0, so we don't need to check whether the return value is 0 or not. This change was first introduced in commit a777e18f1bcd ("bpftool: Use libbpf 1.0 API mode instead of RLIMIT_MEMLOCK"), but later reverted to restore the unconditional rlimit bump in bpftool. Let's re-add it. Co-developed-by: Yafang Shao Signed-off-by: Quentin Monnet Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20220610112648.29695-3-quentin@isovalent.com

Revert "bpftool: Use libbpf 1.0 API mode instead of RLIMIT_MEMLOCK"

2022-06-14T20:18:06+00:00

This reverts commit a777e18f1bcd32528ff5dfd10a6629b655b05eb8. In commit a777e18f1bcd ("bpftool: Use libbpf 1.0 API mode instead of RLIMIT_MEMLOCK"), we removed the rlimit bump in bpftool, because the kernel has switched to memcg-based memory accounting. Thanks to the LIBBPF_STRICT_AUTO_RLIMIT_MEMLOCK, we attempted to keep compatibility with other systems and ask libbpf to raise the limit for us if necessary. How do we know if memcg-based accounting is supported? There is a probe in libbpf to check this. But this probe currently relies on the availability of a given BPF helper, bpf_ktime_get_coarse_ns(), which landed in the same kernel version as the memory accounting change. This works in the generic case, but it may fail, for example, if the helper function has been backported to an older kernel. This has been observed for Google Cloud's Container-Optimized OS (COS), where the helper is available but rlimit is still in use. The probe succeeds, the rlimit is not raised, and probing features with bpftool, for example, fails. A patch was submitted [0] to update this probe in libbpf, based on what the cilium/ebpf Go library does [1]. It would lower the soft rlimit to 0, attempt to load a BPF object, and reset the rlimit. But it may induce some hard-to-debug flakiness if another process starts, or the current application is killed, while the rlimit is reduced, and the approach was discarded. As a workaround to ensure that the rlimit bump does not depend on the availability of a given helper, we restore the unconditional rlimit bump in bpftool for now. [0] https://lore.kernel.org/bpf/20220609143614.97837-1-quentin@isovalent.com/ [1] https://github.com/cilium/ebpf/blob/v0.9.0/rlimit/rlimit.go#L39 Signed-off-by: Quentin Monnet Signed-off-by: Daniel Borkmann Cc: Yafang Shao Cc: Stanislav Fomichev Link: https://lore.kernel.org/bpf/20220610112648.29695-2-quentin@isovalent.com

bpftool: Fix bootstrapping during a cross compilation

2022-06-09T12:01:21+00:00

This change adjusts the Makefile to use "HOSTAR" as the archive tool to keep the sanity of the build process for the bootstrap part in check. For the rationale, please continue reading. When cross compiling bpftool with buildroot, it leads to an invocation like: $ AR="/path/to/buildroot/host/bin/arc-linux-gcc-ar" \ CC="/path/to/buildroot/host/bin/arc-linux-gcc" \ ... make Which in return fails while building the bootstrap section: ----------------------------------8<---------------------------------- make: Entering directory '/src/bpftool-v6.7.0/src' ... libbfd: [ on ] ... disassembler-four-args: [ on ] ... zlib: [ on ] ... libcap: [ OFF ] ... clang-bpf-co-re: [ on ] <-- triggers bootstrap . . . LINK /src/bpftool-v6.7.0/src/bootstrap/bpftool /usr/bin/ld: /src/bpftool-v6.7.0/src/bootstrap/libbpf/libbpf.a: error adding symbols: archive has no index; run ranlib to add one collect2: error: ld returned 1 exit status make: *** [Makefile:211: /src/bpftool-v6.7.0/src/bootstrap/bpftool] Error 1 make: *** Waiting for unfinished jobs.... AR /src/bpftool-v6.7.0/src/libbpf/libbpf.a make[1]: Leaving directory '/src/bpftool-v6.7.0/libbpf/src' make: Leaving directory '/src/bpftool-v6.7.0/src' ---------------------------------->8---------------------------------- This occurs because setting "AR" confuses the build process for the bootstrap section and it calls "arc-linux-gcc-ar" to create and index "libbpf.a" instead of the host "ar". Signed-off-by: Shahab Vahedi Signed-off-by: Daniel Borkmann Reviewed-by: Quentin Monnet Cc: Jean-Philippe Brucker Link: https://lore.kernel.org/bpf/8d297f0c-cfd0-ef6f-3970-6dddb3d9a87a@synopsys.com

bpftool: Add btf enum64 support

2022-06-07T17:20:43+00:00

Add BTF_KIND_ENUM64 support. For example, the following enum is defined in uapi bpf.h. $ cat core.c enum A { BPF_F_INDEX_MASK = 0xffffffffULL, BPF_F_CURRENT_CPU = BPF_F_INDEX_MASK, BPF_F_CTXLEN_MASK = (0xfffffULL << 32), } g; Compiled with clang -target bpf -O2 -g -c core.c Using bpftool to dump types and generate format C file: $ bpftool btf dump file core.o ... [1] ENUM64 'A' encoding=UNSIGNED size=8 vlen=3 'BPF_F_INDEX_MASK' val=4294967295ULL 'BPF_F_CURRENT_CPU' val=4294967295ULL 'BPF_F_CTXLEN_MASK' val=4503595332403200ULL $ bpftool btf dump file core.o format c ... enum A { BPF_F_INDEX_MASK = 4294967295ULL, BPF_F_CURRENT_CPU = 4294967295ULL, BPF_F_CTXLEN_MASK = 4503595332403200ULL, }; ... Note that for raw btf output, the encoding (UNSIGNED or SIGNED) is printed out as well. The 64bit value is also represented properly in BTF and C dump. Acked-by: Andrii Nakryiko Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20220607062652.3722649-1-yhs@fb.com Signed-off-by: Alexei Starovoitov

bpftool: Check for NULL ptr of btf in codegen_asserts

2022-06-02T23:26:43+00:00

bpf_object__btf() can return a NULL value. If bpf_object__btf returns null, do not progress through codegen_asserts(). This avoids a null ptr dereference at the call btf__type_cnt() in the function find_type_for_map() Signed-off-by: Michael Mullin Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220523194917.igkgorco42537arb@jup

bpftool: Use libbpf_bpf_link_type_str

2022-06-02T23:26:38+00:00

This change switches bpftool over to using the recently introduced libbpf_bpf_link_type_str function instead of maintaining its own string representation for the bpf_link_type enum. Signed-off-by: Daniel Müller Signed-off-by: Andrii Nakryiko Acked-by: Quentin Monnet Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20220523230428.3077108-13-deso@posteo.net

bpftool: Use libbpf_bpf_attach_type_str

2022-06-02T23:26:30+00:00

This change switches bpftool over to using the recently introduced libbpf_bpf_attach_type_str function instead of maintaining its own string representation for the bpf_attach_type enum. Note that contrary to other enum types, the variant names that bpftool maps bpf_attach_type to do not adhere a simple to follow rule. With bpf_prog_type, for example, the textual representation can easily be inferred by stripping the BPF_PROG_TYPE_ prefix and lowercasing the remaining string. bpf_attach_type violates this rule for various variants. We decided to fix up this deficiency with this change, meaning that bpftool uses the same textual representations as libbpf. Supporting tests, completion scripts, and man pages have been adjusted accordingly. However, we did add support for accepting (the now undocumented) original attach type names when they are provided by users. For the test (test_bpftool_synctypes.py), I have removed the enum representation checks, because we no longer mirror the various enum variant names in bpftool source code. For the man page, help text, and completion script checks we are now using enum definitions from uapi/linux/bpf.h as the source of truth directly. Signed-off-by: Daniel Müller Signed-off-by: Andrii Nakryiko Acked-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20220523230428.3077108-10-deso@posteo.net

bpftool: Use libbpf_bpf_map_type_str

2022-06-02T23:26:24+00:00

This change switches bpftool over to using the recently introduced libbpf_bpf_map_type_str function instead of maintaining its own string representation for the bpf_map_type enum. Signed-off-by: Daniel Müller Signed-off-by: Andrii Nakryiko Acked-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20220523230428.3077108-7-deso@posteo.net

bpftool: Use libbpf_bpf_prog_type_str

2022-06-02T23:26:18+00:00

This change switches bpftool over to using the recently introduced libbpf_bpf_prog_type_str function instead of maintaining its own string representation for the bpf_prog_type enum. Signed-off-by: Daniel Müller Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song Acked-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20220523230428.3077108-4-deso@posteo.net

bpftool: Use sysfs vmlinux when dumping BTF by ID

2022-05-13T23:07:53+00:00

Currently, dumping almost all BTFs specified by id requires using the -B option to pass the base BTF. For kernel module BTFs the vmlinux BTF sysfs path should work. This patch simplifies dumping by ID usage by loading vmlinux BTF from sysfs as base, if base BTF was not specified and the ID corresponds to a kernel module BTF. Signed-off-by: Larysa Zaremba Signed-off-by: Andrii Nakryiko Reviewed-by: Alexander Lobakin Link: https://lore.kernel.org/bpf/20220513121743.12411-1-larysa.zaremba@intel.com