About unexpected restarts
Facing kernel panic on accessing 'Offline' attribute of SMB protocol in our custom kext. How to debug these kernel panics on MAC OS Catalina. The debugging kernel extension steps are not supported for Catalina because of Read-only file system. Also kext with IOKit.framework does not load on MAC OS 10.14.x with error. Apr 06, 2020 Other users on macOS 10.15.4 have experienced crashes after waking their Mac from sleep, with affected systems suffering a kernel panic and rebooting to the Apple logo, according to comments shared. Under Mac OS X 10.6, panic logs are saved in the Macintosh HD Library DiagnosticReports folder. The kernel panic screen will vary depending on which version of Mac OS X or macOS you're using. Mac OS X 7 (Lion) and higher will display a message that starts with, 'Your computer shut down because of a problem.' Mac OS X 6 (Snow Leopard) and earlier will display a message that starts with, 'You need to restart your computer.' Founded as a Mac software company in 1997, our joy at Panic comes from building things that feel truly, well, Mac-like. Long ago, we created Coda, an all-in-one Mac web editor that broke new ground. But when we started work on Nova, we looked at where the web was today, and where we needed to be. It was time for a fresh start.
Rarely, your Mac might experience a software or hardware issue that requires it to restart. When it starts up again, you might see a message that your computer was restarted because of a problem.
Unexpected restarts are usually caused by software installed on your Mac, or by devices connected to your Mac. If the issue causes your Mac to restart every time it attempts to start up, your Mac might eventually shut down. Use the steps below to check the software and hardware on your Mac.
Check your software
If the issue is caused by software on your Mac, one of these steps might help:
- Install all available software updates.
- If your Mac suspects that a particular app caused the restart, it might ask whether you would like to move the app to the Trash. Click Move to Trash, then contact the software developer to see if a software update is available.
- Use safe mode to try to isolate the cause of the issue.
- Reinstall macOS. If the issue continues after reinstalling macOS, check your hardware.
Check your hardware
Learn how to check your connected devices and other hardware.
Check peripheral devices first
If you don't have any devices attached to your Mac, skip to the next section.
- Shut down your Mac.
- Disconnect all peripheral devices, such as hard drives or printers. If you have a desktop Mac, make sure that only a display, keyboard, and mouse or trackpad are connected.
- Turn on your Mac.
- Use your Mac for the amount of time that it would usually take for an unexpected restart to occur.
- If an unexpected restart occurs, follow the steps to check the internal RAM and third-party hardware.
- If an unexpected restart doesn't occur, turn off the Mac and connect one peripheral device at a time until an unexpected restart occurs.
Check RAM and third-party hardware
Certain models of Mac computers have removable memory (RAM). If you recently installed memory or a hard disk (or SSD), make sure that it's compatible and installed correctly. If possible, remove it and test with the original memory or disk.
Learn more
- If you continue to experience unexpected restarts, contact Apple Support.
- If your Mac is frequently restarting unexpectedly, it's important to determine the exact steps that lead up to the issue. The next time that your Mac restarts unexpectedly, record the date and time it occurs. These questions might help you diagnose the problem:
- Was the computer starting up, shutting down, or performing a particular task when the unexpected restart happened?
- Is the computer restart random, or does it happen every time you do a certain task?
- Does the restart happen when a specific external device is connected to your Mac or to a specific port?
- Learn what to do if your Mac doesn't turn on or start up.
- Learn about the screens you see when your Mac starts up.
A kernel panic message from a Linux system
Kernel panic in Ubuntu 13.04 (Linux 3.8) in Oracle VM VirtualBox
A kernel panic (sometimes abbreviated as KP[1]) is a safety measure taken by an operating system's kernel upon detecting an internal fatal error in which either it is unable to safely recover or continuing to run the system would have a higher risk of major data loss. The term is largely specific to Unix and Unix-like systems. For Microsoft Windows operating systems the equivalent term is 'Stop error', resulting in a bug check[2] screen that presents the bug check code on a blue background in early versions of Windows (colloquially known as a 'Blue Screen of Death' or BSoD), or on a green background on the Xbox One platform as well as in Windows 10 preview builds.[3]
The kernel routines that handle panics, known as
panic()
in AT&T-derived and BSD Unix source code, are generally designed to output an error message to the console, dump an image of kernel memory to disk for post-mortem debugging, and then either wait for the system to be manually rebooted, or initiate an automatic reboot.[4] The information provided is of a highly technical nature and aims to assist a system administrator or software developer in diagnosing the problem. Kernel panics can also be caused by errors originating outside kernel space. For example, many Unix operating systems panic if the init process, which runs in user space, terminates.[5][6]History[edit]
The Unix kernel maintains internal consistency and runtime correctness with assertions as the fault detection mechanism. The basic assumption is that the hardware and the software should perform correctly and a failure of an assertion results in a panic, i.e. a voluntary halt to all system activity.[7] The kernel panic was introduced in an early version of Unix and demonstrated a major difference between the design philosophies of Unix and its predecessor Multics. Multics developer Tom van Vleck recalls a discussion of this change with Unix developer Dennis Ritchie:
I remarked to Dennis that easily half the code I was writing in Multics was error recovery code. He said, 'We left all that stuff out. If there's an error, we have this routine called panic, and when it is called, the machine crashes, and you holler down the hall, 'Hey, reboot it.'[8]
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The original
panic()
function was essentially unchanged from Fifth Edition UNIX to the VAX-based UNIX 32V and output only an error message with no other information, then dropped the system into an endless idle loop.Source code of
panic()
function in V6 UNIX:[9]As the Unix codebase was enhanced, the
panic()
function was also enhanced to dump various forms of debugging information to the console.Causes[edit]
A panic may occur as a result of a hardware failure or a software bug in the operating system. In many cases, the operating system is capable of continued operation after an error has occurred. However, the system is in an unstable state and rather than risking security breaches and data corruption, the operating system stops to prevent further damage and facilitate diagnosis of the error and, in usual cases, restart.[10]
After recompiling a kernel binary image from source code, a kernel panic while booting the resulting kernel is a common problem if the kernel was not correctly configured, compiled or installed.[11] Add-on hardware or malfunctioning RAM could also be sources of fatal kernel errors during start up, due to incompatibility with the OS or a missing device driver.[12] A kernel may also go into
panic()
if it is unable to locate a root file system.[13] During the final stages of kernel userspace initialization, a panic is typically triggered if the spawning of init fails. A panic might also be triggered if the init process terminates, as the system would then be unusable.[14]The following is an implementation of the Linux kernel final initialization in
kernel_init()
:[15]Operating system specifics[edit]
Linux[edit]
Kernel panic as seen on an iKVM console
Kernel panics appear in Linux like in other Unix-like systems, but they can also generate another kind of error condition, known as a kernel oops.[16] In this case, the kernel normally continues to run after killing the offending process. As an oops could cause some subsystems or resources to become unavailable, they can later lead to a full kernel panic.
On Linux, a kernel panic causes keyboard LEDs to blink as a visual indication of a critical condition.[17]
macOS[edit]
When a kernel panic occurs in Mac OS X 10.2 through 10.7, the computer displays a multilingual message informing the user that they need to reboot the system.[18] Prior to 10.2, a more traditional Unix-style panic message was displayed; in 10.8 and later, the computer automatically reboots and displays a message after the restart. The format of the message varies from version to version:[19]
- 10.0–10.1: The system displays text on the screen, giving details about the error, and becomes unresponsive.
- 10.2: Rolls down a black transparent curtain then displays a message on a white background informing the user that they should restart the computer. The message is shown in English, French, German and Japanese.
- 10.3–10.5: The kernel panic is almost the same as version 10.2 but the background of the error screen is black.
- 10.6–10.7-10.8: The text has been revised and now includes a Spanish translation.
- 10.9 and later: The computer becomes unresponsive before it immediately reboots. When the computer starts back up, it shows a warning message for a few seconds about the computer restarting because of a kernel panic, and then the computer restarts back up. The message now includes a Chinese translation.
Sometimes when there are five or more kernel panics within three minutes of the first one, the Mac will display a prohibitory sign for 30 seconds, and then shut down (this is known as a 'recurring kernel panic').
In all versions above 10.2, the text is superimposed on a standby symbol and is not full screen. Debugging information is saved in NVRAM and written to a log file on reboot. In 10.7 there is a feature to automatically restart after a kernel panic. In some cases, on 10.2 and later, white text detailing the error may appear in addition to the standby symbol.
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- Mac OS X 10.0–10.1 kernel panic
- Mac OS X 10.2 kernel panic
- Mac OS X 10.3–10.5 kernel panic
- Mac OS X 10.6 and 10.7 kernel panic
- Message shown after the computer restarts because of a kernel panic in OS X 10.8 and later versions
Mac Os Catalina
See also[edit]
Wikimedia Commons has media related to Kernel panic. |
References[edit]
Mac Os Download
- ^'KP - Kernel Panic (Linux) | AcronymFinder'. www.acronymfinder.com. Retrieved January 6, 2016.
- ^'Bug Checks (Blue Screens)'. Hardware Dev Center - Microsoft.
- ^Hoffman, Chris. 'Did You Know Windows 10 Has a Green Screen of Death?'. How-To Geek. Retrieved June 4, 2020.
- ^'FreeBSD 11.0 - man page for panic (freebsd section 9) - Unix & Linux Commands'. www.unix.com.
- ^'boot failure-init died - Unix Linux Forums - HP-UX'. www.unix.com.
- ^Randolph J. Herber (September 1, 1999). 'Re: PANIC: init died'. Newsgroup: comp.sys.sgi.admin.
- ^Daniel P. Siewiorek; Robert S. Swarz (1998). Reliable computer systems: design and evaluation. A K Peters, Ltd. p. 622. ISBN978-1-56881-092-8. Retrieved May 6, 2011.
- ^'Unix and Multics'. www.multicians.org.
- ^Source code /usr/sys/ken/prf.c from V6 UNIX
- ^Steven M. Hancock (November 22, 2002). Tru64 UNIX troubleshooting: diagnosing and correcting system problemsHP Technologies SeriesITPro collection. Digital Press. pp. 119–126. ISBN978-1-55558-274-6. Retrieved May 3, 2011.
- ^Michael Jang (2006). Linux annoyances for geeks. O'Reilly Media, Inc. pp. 267–274. ISBN978-0-596-00801-7. Retrieved April 29, 2011.
- ^David Pogue (December 17, 2009). Switching to the Mac: The Missing Manual, Snow Leopard Edition. O'Reilly Media, Inc. p. 589. ISBN978-0-596-80425-1. Retrieved May 4, 2011.
- ^Greg Kroah-Hartman (2007). Linux kernel in a nutshell. O'Reilly Media, Inc. p. 59. ISBN978-0-596-10079-7. Retrieved May 3, 2011.
- ^Wolfgang Mauerer (September 26, 2008). Professional Linux Kernel Architecture. John Wiley and Sons. pp. 1238–1239. ISBN978-0-470-34343-2. Retrieved May 3, 2011.
- ^linux/init/main.c, LXR Cross Referencer
- ^'Linux Device Drivers, Chapter 4'(PDF).
- ^James Kirkland; David Carmichael; Christopher L. Tinker; Gregory L. Tinker (May 2006). Linux Troubleshooting for System Administrators and Power Users. Prentice Hall. p. 62. ISBN9780132797399. Retrieved February 5, 2016.
- ^'OS X: About kernel panics - Apple Support'. support.apple.com.
- ^'A New Screen of Death for Mac OS X'. OSXBook.com.
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