19 May, 2020
1 commit
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Currently, the kprobe BPF program attachment method for bpf_load is
quite old. The implementation of bpf_load "directly" controls and
manages(create, delete) the kprobe events of DEBUGFS. On the other hand,
using using the libbpf automatically manages the kprobe event.
(under bpf_link interface)By calling bpf_program__attach(_kprobe) in libbpf, the corresponding
kprobe is created and the BPF program will be attached to this kprobe.
To remove this, by simply invoking bpf_link__destroy will clean up the
event.This commit refactors kprobe tracing programs (tracex{1~7}_user.c) with
libbpf using bpf_link interface and bpf_program__attach.tracex2_kern.c, which tracks system calls (sys_*), has been modified to
append prefix depending on architecture.Signed-off-by: Daniel T. Lee
Signed-off-by: Daniel Borkmann
Acked-by: Yonghong Song
Link: https://lore.kernel.org/bpf/20200516040608.1377876-3-danieltimlee@gmail.com
24 Mar, 2020
1 commit
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To reduce the reliance of trace samples (trace*_user) on bpf_load,
move read_trace_pipe to trace_helpers. By moving this bpf_loader helper
elsewhere, trace functions can be easily migrated to libbbpf.Signed-off-by: Daniel T. Lee
Signed-off-by: Daniel Borkmann
Acked-by: Andrii Nakryiko
Link: https://lore.kernel.org/bpf/20200321100424.1593964-2-danieltimlee@gmail.com
15 May, 2018
1 commit
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There are two files in the tree called libbpf.h which is becoming
problematic. Most samples don't actually need the local libbpf.h
they simply include it to get to bpf/bpf.h. Include bpf/bpf.h
directly instead.Signed-off-by: Jakub Kicinski
Acked-by: Jesper Dangaard Brouer
Signed-off-by: Alexei Starovoitov
02 Nov, 2017
1 commit
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Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.By default all files without license information are under the default
license of the kernel, which is GPL version 2.Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if
Reviewed-by: Philippe Ombredanne
Reviewed-by: Thomas Gleixner
Signed-off-by: Greg Kroah-Hartman
02 Apr, 2015
1 commit
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tracex1_kern.c - C program compiled into BPF.
It attaches to kprobe:netif_receive_skb()
When skb->dev->name == "lo", it prints sample debug message into
trace_pipe via bpf_trace_printk() helper function.tracex1_user.c - corresponding user space component that:
- loads BPF program via bpf() syscall
- opens kprobes:netif_receive_skb event via perf_event_open()
syscall
- attaches the program to event via ioctl(event_fd,
PERF_EVENT_IOC_SET_BPF, prog_fd);
- prints from trace_pipeNote, this BPF program is non-portable. It must be recompiled
with current kernel headers. kprobe is not a stable ABI and
BPF+kprobe scripts may no longer be meaningful when kernel
internals change.No matter in what way the kernel changes, neither the kprobe,
nor the BPF program can ever crash or corrupt the kernel,
assuming the kprobes, perf and BPF subsystem has no bugs.The verifier will detect that the program is using
bpf_trace_printk() and the kernel will print 'this is a DEBUG
kernel' warning banner, which means that bpf_trace_printk()
should be used for debugging of the BPF program only.Usage:
$ sudo tracex1
ping-19826 [000] d.s2 63103.382648: : skb ffff880466b1ca00 len 84
ping-19826 [000] d.s2 63103.382684: : skb ffff880466b1d300 len 84ping-19826 [000] d.s2 63104.382533: : skb ffff880466b1ca00 len 84
ping-19826 [000] d.s2 63104.382594: : skb ffff880466b1d300 len 84Signed-off-by: Alexei Starovoitov
Cc: Arnaldo Carvalho de Melo
Cc: Arnaldo Carvalho de Melo
Cc: Daniel Borkmann
Cc: David S. Miller
Cc: Jiri Olsa
Cc: Linus Torvalds
Cc: Masami Hiramatsu
Cc: Namhyung Kim
Cc: Peter Zijlstra
Cc: Peter Zijlstra
Cc: Steven Rostedt
Link: http://lkml.kernel.org/r/1427312966-8434-7-git-send-email-ast@plumgrid.com
Signed-off-by: Ingo Molnar
