imported>LucasPayne: Fix date of reference

2024-12-03T15:12:00Z

Fix date of reference

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{{Short description|Serious, non-fatal error in the Linux kernel}}
[[File:Linux_2.4_oops_sparc.png|thumb|upright=1.15|Linux kernel oops on [[SPARC]]]]
[[File:Linux-2.6-oops-parisc.jpg|thumb|right|Linux kernel oops on [[PA-RISC]] with a dead [[cowsay|ASCII cow]]]]

In [[computing]], an '''oops''' is a serious but non-fatal error in the [[Linux kernel]]. An oops may precede a [[kernel panic]], but it may also allow continued operation with compromised [[Reliability engineering|reliability]]. The term does not stand for anything, other than that it is a simple mistake.

==Functioning==
When the kernel detects a problem, it [[kill (Unix)|kill]]s any offending [[Process (computing)|processes]] and prints an ''oops message'', which Linux kernel engineers can use in [[debugging]] the [[Fault (technology)|condition]] that created the oops and [[Patch (computing)|fixing]] the underlying programming error. After a system has experienced an oops, some internal resources may no longer be operational. Thus, even if the system appears to work correctly, undesirable side effects may have resulted from the active task being killed. A kernel oops often leads to a [[kernel panic]] when the system attempts to use resources that have been lost. Some kernels are configured to panic when many oopses ({{formatnum:10000}} by default) have occurred.<ref>{{cite web|url=https://lore.kernel.org/all/20221107201317.324457-1-jannh@google.com/|title=[PATCH] exit: Put an upper limit on how often we can oops|last=Horn|first=Jann|date=7 November 2022|website=lore.kernel.org|access-date=31 January 2023}}</ref><ref>{{cite web|url=https://docs.kernel.org/admin-guide/sysctl/kernel.html#oops-limit|title=Documentation for /proc/sys/kernel/|website=docs.kernel.org|access-date=31 January 2023}}</ref> This oops limit is due to the potential, for example, for attackers to repeatedly trigger an oops and an associated [[resource leak]], which eventually [[integer overflow|overflows an integer]] and allows further exploitation.<ref>{{ cite web | url = https://lwn.net/Articles/914878/ | title = Averting excessive oopses | work = [[LWN.net]] | last = Corbet | first = Jonathan | date = 18 November 2022 }}</ref><ref>{{ cite web | url = https://googleprojectzero.blogspot.com/2023/01/exploiting-null-dereferences-in-linux.html | publisher = [[Google Project Zero]] | title = Exploiting null-dereferences in the Linux kernel | date = 19 January 2023 | last = Jenkins | first = Seth }}</ref>

The official Linux kernel documentation regarding oops messages resides in the file {{Mono|Documentation/admin-guide/bug-hunting.rst}}<ref>{{cite web |url=https://www.kernel.org/doc/Documentation/admin-guide/bug-hunting.rst |title=bug-hunting |website=kernel.org}}</ref> of the kernel sources. Some logger configurations may affect the ability to collect oops messages.<ref>{{cite web |url=http://madwifi-project.org/wiki/DevDocs/KernelOops |title=DevDocs/KernelOops |website=madwifi-project.org |access-date=2010-08-21 |archive-date=2020-08-03 |archive-url=https://web.archive.org/web/20200803071136/http://madwifi-project.org/wiki/DevDocs/KernelOops |url-status=dead }}</ref> The <code>kerneloops</code> software can collect and submit kernel oopses to a repository such as the www.kerneloops.org website,<ref>{{cite web |url=https://linux.die.net/man/8/kerneloops|title=kerneloops(8) - Linux man page|access-date=31 January 2023}}</ref> which provides statistics and public access to reported oopses.

A simplified crash screen was introduced in Linux 6.10, similar to the [[Blue Screen of Death]] on Windows.<ref>{{Cite web|url=https://www.phoronix.com/news/Linux-6.10-DRM-Panic-Handler|title=Linux 6.10 Preps A Kernel Panic Screen - Sort Of A "Blue Screen of Death" - Phoronix|last=Larabel|first=Michael|date=19 April 2024|website=Phoronix}}</ref>

== See also ==
* [[kdump (Linux)]]{{snd}} Linux kernel's crash dump mechanism, which internally uses [[kexec]]
* [[System.map]]{{snd}} contains mappings between symbol names and their addresses in memory, used to interpret oopses

== References ==
{{Reflist}}

== Further reading ==
* [https://lwn.net/images/pdf/LDD3/ch04.pdf ''Linux Device Drivers'', 3rd edition, Chapter 4.]
* {{cite mailing list
|title = Re: what's an OOPS
|author = John Bradford
|date = 2003-03-08
|mailing-list = [[Linux kernel mailing list|LKML]]
|url = http://www.ussg.iu.edu/hypermail/linux/kernel/0303.1/0009.html
|access-date = 2006-05-22
|url-status = dead
|archive-url = https://web.archive.org/web/20070310214850/http://www.ussg.iu.edu/hypermail/linux/kernel/0303.1/0009.html
|archive-date = 2007-03-10
}}
* {{cite mailing list
|title = Re: what's an OOPS
|author = Szakacsits Szabolcs
|date = 2003-03-08
|mailing-list = LKML
|url = http://www.ussg.iu.edu/hypermail/linux/kernel/0303.1/0027.html
|access-date = 2006-05-22
|url-status = dead
|archive-url = https://web.archive.org/web/20070313235208/http://www.ussg.iu.edu/hypermail/linux/kernel/0303.1/0027.html
|archive-date = 2007-03-13
}}
* {{cite mailing list
| title = OOPS report analysis
| author = Al Viro
| date = 2008-01-14
| mailing-list = LKML
| url = http://article.gmane.org/gmane.linux.kernel/624292
| access-date = 2008-01-14
| archive-url = https://web.archive.org/web/20080421030623/http://article.gmane.org/gmane.linux.kernel/624292
| archive-date = 2008-04-21
| url-status = dead
}}
* [http://madwifi-project.org/wiki/DevDocs/KernelOops Kernel Oops Howto (the madwifi project)] {{Webarchive|url=https://web.archive.org/web/20200803071136/http://madwifi-project.org/wiki/DevDocs/KernelOops |date=2020-08-03 }} Useful information on configuration files and tools to help display oops messages. Also many other links.

{{Linux kernel}}
{{Linux}}
{{Error messages}}

[[Category:Computer errors]]
[[Category:Linux kernel]]
[[Category:Screens of death]]

Linux kernel oops - Revision history

imported>LucasPayne: Fix date of reference