Eric Lee / smarc-fsl-linux-kernel

06 Feb, 2016

1 commit

16 Jun, 2015

1 commit

  • ffeedafbf   bpf: introduce current->pid, tgid, uid, gid, comm accessors ... Browse Code »

    eBPF programs attached to kprobes need to filter based on
    current->pid, uid and other fields, so introduce helper functions:

    u64 bpf_get_current_pid_tgid(void)
    Return: current->tgid << 32 | current->pid

    u64 bpf_get_current_uid_gid(void)
    Return: current_gid << 32 | current_uid

    bpf_get_current_comm(char *buf, int size_of_buf)
    stores current->comm into buf

    They can be used from the programs attached to TC as well to classify packets
    based on current task fields.

    Update tracex2 example to print histogram of write syscalls for each process
    instead of aggregated for all.

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

    Alexei Starovoitov
     

02 Apr, 2015

1 commit

  • d822a1926   samples/bpf: Add counting example for kfree_skb() function calls and the write() syscall ... Browse Code »

    this example has two probes in one C file that attach to
    different kprove events and use two different maps.

    1st probe is x64 specific equivalent of dropmon. It attaches to
    kfree_skb, retrevies 'ip' address of kfree_skb() caller and
    counts number of packet drops at that 'ip' address. User space
    prints 'location - count' map every second.

    2nd probe attaches to kprobe:sys_write and computes a histogram
    of different write sizes

    Usage:
    $ sudo tracex2
    location 0xffffffff81695995 count 1
    location 0xffffffff816d0da9 count 2

    location 0xffffffff81695995 count 2
    location 0xffffffff816d0da9 count 2

    location 0xffffffff81695995 count 3
    location 0xffffffff816d0da9 count 2

    557145+0 records in
    557145+0 records out
    285258240 bytes (285 MB) copied, 1.02379 s, 279 MB/s
    syscall write() stats
    byte_size : count distribution
    1 -> 1 : 3 | |
    2 -> 3 : 0 | |
    4 -> 7 : 0 | |
    8 -> 15 : 0 | |
    16 -> 31 : 2 | |
    32 -> 63 : 3 | |
    64 -> 127 : 1 | |
    128 -> 255 : 1 | |
    256 -> 511 : 0 | |
    512 -> 1023 : 1118968 |************************************* |

    Ctrl-C at any time. Kernel will auto cleanup maps and programs

    $ addr2line -ape ./bld_x64/vmlinux 0xffffffff81695995
    0xffffffff816d0da9 0xffffffff81695995:
    ./bld_x64/../net/ipv4/icmp.c:1038 0xffffffff816d0da9:
    ./bld_x64/../net/unix/af_unix.c:1231

    Signed-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/1427312966-8434-8-git-send-email-ast@plumgrid.com
    Signed-off-by: Ingo Molnar

    Alexei Starovoitov