06-C.8: Kernel Module Monitoring
- Page ID
- 32799
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)EXAM OBJECTIVES COVERED
1.2 Given a scenario, install, configure, and monitor kernel modules.
2.7 Explain the use and operation of Linux devices.
The /proc Directory
/proc is very special in that it is also a virtual filesystem. It's sometimes referred to as a process information pseudo-file system. It doesn't contain 'real' files but runtime system information (e.g., system memory, devices mounted, hardware configuration, etc). For this reason, it can be regarded as a control and information center for the kernel. In fact, quite a lot of system utilities are simply calls to files in this directory. For example, 'lsmod' is the same as 'cat /proc/modules' while 'lspci' is a synonym for 'cat /proc/pci'. By altering files located in this directory you can even read/change kernel parameters (sysctl) while the system is running.
The most distinctive thing about files in this directory is the fact that all of them have a file size of 0, with the exception of kcore, mtrr and self.
| Directories | Contents |
|---|---|
| /proc/cmdline | Options passed to the kernel by the boot loader at boot time, such as mounting the kernel as read-only. |
| /proc/cpuinfo | Information about the processor, such as its type, make, model, and performance. |
| /proc/devices | List of device drivers configured into the currently running kernel. |
| /proc/filesystems | Filesystems configured into the kernel. |
| /proc/interrupts | Shows which interrupts are in use, and how many of each there have been. |
| /proc/ioports | Which I/O ports are in use at the moment. |
| /proc/meminfo | Information about memory usage, both physical and swap. |
| /proc/modules | Which kernel modules are loaded at the moment. |
| /proc/net | Status information about network protocols. |
| /proc/stat | Various statistics about the system, such as the number of page faults since the system was booted. |
| /proc/uptime | The length of time the kernel has been running since boot and spent in idle mode (both in seconds). |
In Linux, you can also find the kernel information in the file /proc/version. Just look at the contents of this file:
pbmac@pbmac-server $ cat /proc/version
Linux version 4.15.0-91-generic (buildd@lgw01-amd64-013) (gcc version 7.4.0 (Ubuntu 7.4.0-1ubuntu1~18.04.1))
#92-Ubuntu SMP Fri Feb 28 11:09:48 UTC 2020
You’ll see an output similar to what you saw with uname. Remember what all the digits mean here? Here is an explanation:
- 4 – Kernel version
- 15 – Major revision
- 0 – Minor revision
- 91 – Bug fix
- generic – Distribution-specific string. For Ubuntu, it means I’m using the desktop version. For Ubuntu server edition, it would be ‘server.’
There is other information in this output as well:
- Linux – Kernel name. If you run the same command on BSD or MacOS, the result will be different.
- 4.15.0-91-generic – Kernel release (as we saw above).
- buildd@lgw01-amd64-013 – Username who compiled the kernel.
- 7.4.0 – GCC version (GCC is the C compiler used to compile the kernel).
- #92-Ubuntu SMP Fri Feb 28 11:09:48 UTC 2020 – This means that Ubuntu has compiled 4.15.0-91-generic 92 times. A timestamp for the last compilation is also there.
Adapted from:
"3 Ways to Check Linux Kernel Version in Command Line" by Abhishek Prakash, It's FOSS is licensed under CC BY-SA 4.0
"1.14. /proc" by Multiple contributors, The Linux Documentation Project is licensed under CC BY-SA 3.0
"3.7. The /proc filesystem" by Multiple contributors, The Linux Documentation Project is licensed under CC BY-SA 3.0