NAME¶

mountsnoop - Trace mount() and umount() syscalls. Uses Linux eBPF/bcc.

SYNOPSIS¶

mountsnoop

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.

REQUIREMENTS¶

CONFIG_BPF and bcc.

FIELDS¶

COMM

Process name

PID

Process ID

TID

Thread ID

MNT_NS

Mount namespace inode number

CALL

System call, arguments, and return value

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.

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¶

Omar Sandoval

SEE ALSO¶

mount(2) umount(2)