---
name: "killsnoop-bpfcc"
section: "8"
platform: "linux"
package: "bpfcc-tools"
version: "0.31.0+ds-7"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/killsnoop-bpfcc"
---

# killsnoop-bpfcc(8)

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

## 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 (filtered in-kernel).

- \-T PID

  Trace this target process ID only which is the receiver of signal (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)](/signal/7.md).

- 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)](/opensnoop/8.md), [funccount(8)](/funccount/8.md)