19 May, 2020

1 commit

  • 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

    Daniel T. Lee
     

15 May, 2018

1 commit


04 Nov, 2017

1 commit


02 Nov, 2017

1 commit

  • 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

    Greg Kroah-Hartman
     

08 Oct, 2017

1 commit


05 Jun, 2017

1 commit

  • $ trace_event

    tests attaching BPF program to HW_CPU_CYCLES, SW_CPU_CLOCK, HW_CACHE_L1D and other events.
    It runs 'dd' in the background while bpf program collects user and kernel
    stack trace on counter overflow.
    User space expects to see sys_read and sys_write in the kernel stack.

    $ tracex6

    tests reading of various perf counters from BPF program.

    Both tests were refactored to increase coverage and be more accurate.

    Signed-off-by: Teng Qin
    Signed-off-by: Alexei Starovoitov
    Signed-off-by: David S. Miller

    Teng Qin
     

20 Dec, 2016

1 commit

  • This declaration was made in samples/bpf/libbpf.c for convenience, but
    there's already one in tools/perf/perf-sys.h. Reuse that one.

    Committer notes:

    Testing it:

    $ make -j4 O=../build/v4.9.0-rc8+ samples/bpf/
    make[1]: Entering directory '/home/build/v4.9.0-rc8+'
    CHK include/config/kernel.release
    GEN ./Makefile
    CHK include/generated/uapi/linux/version.h
    Using /home/acme/git/linux as source for kernel
    CHK include/generated/utsrelease.h
    CHK include/generated/timeconst.h
    CHK include/generated/bounds.h
    CHK include/generated/asm-offsets.h
    CALL /home/acme/git/linux/scripts/checksyscalls.sh
    HOSTCC samples/bpf/test_verifier.o
    HOSTCC samples/bpf/libbpf.o
    HOSTCC samples/bpf/../../tools/lib/bpf/bpf.o
    HOSTCC samples/bpf/test_maps.o
    HOSTCC samples/bpf/sock_example.o
    HOSTCC samples/bpf/bpf_load.o

    HOSTLD samples/bpf/trace_event
    HOSTLD samples/bpf/sampleip
    HOSTLD samples/bpf/tc_l2_redirect
    make[1]: Leaving directory '/home/build/v4.9.0-rc8+'
    $

    Also tested the offwaketime resulting from the rebuild, seems to work as
    before.

    Signed-off-by: Joe Stringer
    Tested-by: Arnaldo Carvalho de Melo
    Cc: Alexei Starovoitov
    Cc: Daniel Borkmann
    Cc: Wang Nan
    Link: http://lkml.kernel.org/r/20161209024620.31660-7-joe@ovn.org
    [ Use -I$(srctree)/tools/lib/ to support out of source code tree builds ]
    Signed-off-by: Arnaldo Carvalho de Melo

    Joe Stringer
     

16 Dec, 2016

1 commit

  • Switch all of the sample code to use the function names from
    tools/lib/bpf so that they're consistent with that, and to declare their
    own log buffers. This allow the next commit to be purely devoted to
    getting rid of the duplicate library in samples/bpf.

    Committer notes:

    Testing it:

    On a fedora rawhide container, with clang/llvm 3.9, sharing the host
    linux kernel git tree:

    # make O=/tmp/build/linux/ headers_install
    # make O=/tmp/build/linux -C samples/bpf/

    Since I forgot to make it privileged, just tested it outside the
    container, using what it generated:

    # uname -a
    Linux jouet 4.9.0-rc8+ #1 SMP Mon Dec 12 11:20:49 BRT 2016 x86_64 x86_64 x86_64 GNU/Linux
    # cd /var/lib/docker/devicemapper/mnt/c43e09a53ff56c86a07baf79847f00e2cc2a17a1e2220e1adbf8cbc62734feda/rootfs/tmp/build/linux/samples/bpf/
    # ls -la offwaketime
    -rwxr-xr-x. 1 root root 24200 Dec 15 12:19 offwaketime
    # file offwaketime
    offwaketime: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=c940d3f127d5e66cdd680e42d885cb0b64f8a0e4, not stripped
    # readelf -SW offwaketime_kern.o | grep PROGBITS
    [ 2] .text PROGBITS 0000000000000000 000040 000000 00 AX 0 0 4
    [ 3] kprobe/try_to_wake_up PROGBITS 0000000000000000 000040 0000d8 00 AX 0 0 8
    [ 5] tracepoint/sched/sched_switch PROGBITS 0000000000000000 000118 000318 00 AX 0 0 8
    [ 7] maps PROGBITS 0000000000000000 000430 000050 00 WA 0 0 4
    [ 8] license PROGBITS 0000000000000000 000480 000004 00 WA 0 0 1
    [ 9] version PROGBITS 0000000000000000 000484 000004 00 WA 0 0 4
    # ./offwaketime | head -5
    swapper/1;start_secondary;cpu_startup_entry;schedule_preempt_disabled;schedule;__schedule;-;---;; 106
    CPU 0/KVM;entry_SYSCALL_64_fastpath;sys_ioctl;do_vfs_ioctl;kvm_vcpu_ioctl;kvm_arch_vcpu_ioctl_run;kvm_vcpu_block;schedule;__schedule;-;try_to_wake_up;swake_up_locked;swake_up;apic_timer_expired;apic_timer_fn;__hrtimer_run_queues;hrtimer_interrupt;local_apic_timer_interrupt;smp_apic_timer_interrupt;__irqentry_text_start;cpuidle_enter;call_cpuidle;cpu_startup_entry;start_secondary;;swapper/3 2
    Compositor;entry_SYSCALL_64_fastpath;sys_futex;do_futex;futex_wait;futex_wait_queue_me;schedule;__schedule;-;try_to_wake_up;futex_requeue;do_futex;sys_futex;entry_SYSCALL_64_fastpath;;SoftwareVsyncTh 5
    firefox;entry_SYSCALL_64_fastpath;sys_poll;do_sys_poll;poll_schedule_timeout;schedule_hrtimeout_range;schedule_hrtimeout_range_clock;schedule;__schedule;-;try_to_wake_up;pollwake;__wake_up_common;__wake_up_sync_key;pipe_write;__vfs_write;vfs_write;sys_write;entry_SYSCALL_64_fastpath;;Timer 13
    JS Helper;entry_SYSCALL_64_fastpath;sys_futex;do_futex;futex_wait;futex_wait_queue_me;schedule;__schedule;-;try_to_wake_up;do_futex;sys_futex;entry_SYSCALL_64_fastpath;;firefox 2
    #

    Signed-off-by: Joe Stringer
    Tested-by: Arnaldo Carvalho de Melo
    Cc: Alexei Starovoitov
    Cc: Daniel Borkmann
    Cc: Wang Nan
    Cc: netdev@vger.kernel.org
    Link: http://lkml.kernel.org/r/20161214224342.12858-2-joe@ovn.org
    Signed-off-by: Arnaldo Carvalho de Melo

    Joe Stringer
     

13 Aug, 2015

1 commit

  • There are two improvements in this patch:
    1. Fix the build warnings;
    2. Add function read_trace_pipe() to print the result on
    the screen;

    Before this patch, we can get the result through /sys/kernel/de
    bug/tracing/trace_pipe and get nothing on the screen.
    By applying this patch, the result can be printed on the screen.
    $ ./tracex6
    ...
    tracex6-705 [003] d..1 131.428593: : CPU-3 19981414
    sshd-683 [000] d..1 131.428727: : CPU-0 221682321
    sshd-683 [000] d..1 131.428821: : CPU-0 221808766
    sshd-683 [000] d..1 131.428950: : CPU-0 221982984
    sshd-683 [000] d..1 131.429045: : CPU-0 222111851
    tracex6-705 [003] d..1 131.429168: : CPU-3 20757551
    sshd-683 [000] d..1 131.429170: : CPU-0 222281240
    sshd-683 [000] d..1 131.429261: : CPU-0 222403340
    sshd-683 [000] d..1 131.429378: : CPU-0 222561024
    ...

    Signed-off-by: Kaixu Xia
    Acked-by: Alexei Starovoitov
    Signed-off-by: David S. Miller

    Kaixu Xia
     

10 Aug, 2015

1 commit