killsnoop(8) System Manager's Manual killsnoop(8)
NAME
killsnoop - Trace signals issued by the kill() syscall. Uses Linux
eBPF/bcc.
SYNOPSIS
killsnoop [-h] [-x] [-p PID] [-T PID] [-s SIGNAL]
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 which is the sender of signal (fil-
tered in-kernel).
-T PID Trace this target process ID only which is the receiver of sig-
nal (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 target PID 189 only:
# killsnoop -T 189
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)
USER COMMANDS 2015-08-20 killsnoop(8)
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