.TH mountsnoop 8  "2016-10-14" "USER COMMANDS"
.SH NAME
mountsnoop \- Trace mount() and umount() syscalls. Uses Linux eBPF/bcc.
.SH SYNOPSIS
.B mountsnoop
.SH DESCRIPTION
mountsnoop traces the mount() and umount() syscalls, showing which processes
are mounting and unmounting filesystems in what mount namespaces. This can be
useful for troubleshooting system and container setup.

This works by tracing the kernel sys_mount() and sys_umount() functions 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()).

Since this uses BPF, only the root user can use this tool.
.SH REQUIREMENTS
CONFIG_BPF and bcc.
.SH FIELDS
.TP
COMM
Process name
.TP
PID
Process ID
.TP
TID
Thread ID
.TP
MNT_NS
Mount namespace inode number
.TP
CALL
System call, arguments, and return value
.SH OVERHEAD
This traces the kernel mount and umount functions and prints output for each
event. As the rate of these calls is generally expected to be very low, the
overhead is also expected to be negligible. If your system calls mount() and
umount() at a high rate, then test and understand overhead before use.
.SH SOURCE
This is from bcc.
.IP
https://github.com/iovisor/bcc
.PP
Also look in the bcc distribution for a companion _examples.txt file containing
example usage, output, and commentary for this tool.
.SH OS
Linux
.SH STABILITY
Unstable - in development.
.SH AUTHOR
Omar Sandoval
.SH SEE ALSO
mount(2)
umount(2)