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bpftool v7.4

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@github-actions github-actions released this 08 Apr 16:03
· 262 commits to main since this release
v7.4.0
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qmonnet Quentin Monnet
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Breaking change

  • Kernel configuration options related to bpfilter (namely: CONFIG_BPFILTER and CONFIG_BPFILTER_UMH) are no longer checked with bpftool feature probe, following bpfilter's removal in recent kernels. (e725e62)

New features

The information displayed for BPF links (bpftool link list) keeps getting enriched:

  • Display uprobe_multi links. (dd0b761)
  • Display cookie for perf event link probes. (25df69b)
  • Display cookie for kprobe_multi links. (4263cc0)

Other features:

  • Generate shadow variables for struct_ops maps in program skeletons. Shadow types allow skeleton users to easily access the fields of struct_ops maps at runtime. An example program using shadow types is also added to the bpftool-gen manual page. (fc0ad76, 579d6b0)

  • Mark orphaned programs as such when listing programs. Orphaned programs are programs removed in IRQ context, on their way to be unloaded from kernel memory, but possibly passing through audit hooks. Such programs would only be listed on recent kernels. (5b0a3a4)

  • Recognize arena map types (a09e203) and global variables (73a2c7e), and support the addr_space_cast instruction in the disassembler for translated programs, used for working with arena maps (c305ebf).

Bug fixes

  • In the mirror repository, fix the detection of clang-bpf-co-re (for skeletons support) for some clang versions. (515739f)
  • Displaying PIDs for processes holding references to BPF links when listing links with bpftool link list on older kernels broke in v7.3.0, because the internal program pid_iter would fail to load. Fix the program to ensure that pid_iter loads and PIDs are displayed. (3214350)
  • When loading the internal pid_iter program for displaying PIDs of processes holding file descriptors to BPF programs, we would suppress the logs from libbpf. Display them when running bpftool in debug mode (--debug). (0cb4aaf)

Other internal changes

  • Silence build warning from calloc() appearing with recent versions of GCC (supporting -Wcalloc-transposed-args). (c4cc180)
  • Use POSIX's version of basename() for more portability. (6e0d7d0)
  • Improve bpftool's bootstrap build by skipping compilation for some unnecessary object files (3dc1ac6) and passing more relevant values in HOST_CFLAGS and HOST_LDFLAGS (c1adf4a). This also results in more accurate results when listing features with bpftool version for the boostrap bpftool binary.

Known bugs

  • Command bpftool cgroup tree may be broken when running with kernels under v6.1. (#41)
  • When loading multiple programs with bpftool prog loadall and passing a directory name for pinning them that is not located under an existing bpffs, bpftool attempts to mount a new bpffs on the parent of the directory rather than on the directory itself, possibly leading to a portion of the file arborescence to be unexpectedly hidden by the mount. (#100)

Full Changelog: v7.3.0...v7.4.0

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