NAME

       killsnoop - Trace signals issued by the kill() syscall. Uses Linux eBPF/bcc.

SYNOPSIS

       killsnoop [-h] [-x] [-p PID]

DESCRIPTION

       killsnoop  traces  the  kill()  syscall, to show signals sent via this method. This may be
       useful to troubleshoot  failing  applications,  where  an  unknown  mechanism  is  sending
       signals.

       This  works by tracing the kernel sys_kill() function using dynamic tracing, and will need
       updating to match any changes to this function.

       This makes use of a Linux 4.4 feature (bpf_perf_event_output()); for  kernels  older  than
       4.4, see the version under tools/old, which uses an older mechanism.

       Since this uses BPF, only the root user can use this tool.

REQUIREMENTS

       CONFIG_BPF and bcc.

OPTIONS

       -h     Print usage message.

       -x     Only print failed kill() syscalls.

       -p PID Trace this process ID only (filtered in-kernel).

       -s SIGNAL
              Trace this signal only (filtered in-kernel).

EXAMPLES

       Trace all kill() syscalls:
              # killsnoop

       Trace only kill() syscalls that failed:
              # killsnoop -x

       Trace PID 181 only:
              # killsnoop -p 181

       Trace signal 9 only:
              # killsnoop -s 9

FIELDS

       TIME   Time of the kill call.

       PID    Source process ID

       COMM   Source process name

       SIG    Signal number. See signal(7).

       TPID   Target process ID

       RES    Result. 0 == success, a negative value (of the error code) for failure.

OVERHEAD

       This traces the kernel kill function and prints output for each event. As the rate of this
       is generally expected to be low (< 100/s), the overhead is also expected to be negligible.
       If  you  have  an application that is calling a very high rate of kill()s for some reason,
       then test and understand overhead before use.

SOURCE

       This is from bcc.

              https://github.com/iovisor/bcc

       Also look in the bcc distribution for a companion _examples.txt  file  containing  example
       usage, output, and commentary for this tool.

OS

       Linux

STABILITY

       Unstable - in development.

AUTHOR

       Brendan Gregg

SEE ALSO

       opensnoop(8), funccount(8)