A kernel panic displayed on an iMac
. This is the most common form of an operating system failure in Unix-like systems.
Most crashes are the result of executing invalid machine instructions
. Typical causes include incorrect address
values in the program counter
, buffer overflow
, overwriting a portion of the affected program code due to an earlier bug
, accessing invalid memory addresses, using an illegal opcode
or triggering an unhandled exception
. The original software bug that started this chain of events is typically considered to be the cause of the crash, which is discovered through the process of debugging
. The original bug can be far removed from the code
that actually crashed.
In early personal computers, attempting to write data to hardware addresses outside the system's main memory could cause hardware damage. Some crashes are exploitable
and let a malicious program or hacker
execute arbitrary code
allowing the replication of viruses
or the acquisition of data which would normally be inaccessible.
typically crashes when it performs an operation that is not allowed by the operating system. The operating system then triggers an exception
in the application. Unix applications traditionally responded to the signal by dumping core
. Most Windows and Unix GUI
applications respond by displaying a dialogue box (such as the one shown to the right) with the option to attach a debugger
if one is installed. Some applications attempt to recover from the error and continue running instead of exiting
An application can also contain code to crash[a]
after detecting a severe error.
Typical errors that result in application crashes include:
- attempting to read or write memory that is not allocated for reading or writing by that application (segmentation fault) or x86 specific (general protection fault)
- attempting to execute privileged or invalid instructions
- attempting to perform I/O operations on hardware devices to which it does not have permission to access
- passing invalid arguments to system calls
- attempting to access other system resources to which the application does not have permission to access
- attempting to execute machine instructions with bad arguments (depending on CPU architecture): divide by zero, operations on denormal number or NaN (not a number) values, memory access to unaligned addresses, etc.
Crash to desktop
A "crash to desktop" is said to occur when a program
(commonly a video game
) unexpectedly quits, abruptly taking the user back to the desktop
. Usually, the term is applied only to crashes where no error is displayed, hence all the user sees as a result of the crash is the desktop. Many times there is no apparent action that causes a crash to desktop. During normal function, the program may freeze
for a shorter period of time, and then close by itself. Also during normal function, the program may become a black screen
and repeatedly play the last few seconds of sound
(depending on the size of the data buffer
) that was being played before it crashes to desktop. Other times it may appear to be triggered
by a certain action, such as loading an area.
Crash to desktop bugs are considered particularly problematic for users. Since they frequently display no error message, it can be very difficult to track down the source of the problem, especially if the times they occur and the actions taking place right before the crash do not appear to have any pattern or common ground. One way to track down the source of the problem for games is to run them in windowed-mode. Windows Vista
has a feature that can help track down the cause of a CTD problem when it occurs on any program.[clarification needed]
Windows XP included a similar feature as well.[clarification needed]
Some computer programs, such as StepMania
and BBC's Bamzooki
, also crash to desktop if in full-screen, but display the error in a separate window when the user has returned to the desktop.
Web server crashes
The software running the web server
behind a website may crash, rendering it inaccessible entirely or providing only an error message instead of normal content.
For example: if a site is using an SQL database (such as MySQL
) for a script (such as PHP
) and that SQL database server crashes, then PHP
will display a connection error.
Operating system crashes
A kernel panic as displayed in OS X Mountain Lion
An operating system crash commonly occurs when a hardware exception
occurs that cannot be handled
. Operating system crashes can also occur when internal sanity-checking
logic within the operating system detects that the operating system has lost its internal self-consistency.
Modern multi-tasking operating systems, such as Linux
, and macOS
, usually remain unharmed when an application program crashes.
Some operating systems, e.g., z/OS
, have facilities for Reliability, availability and serviceability
(RAS) and the OS can recover from the crash of a critical component, whether due to hardware failure, e.g., uncorrectable ECC error, or to software failure, e.g., a reference to an unassigned page.
Security and privacy implications of crashes
Depending on the application, the crash may contain the user's sensitive and private information.
Moreover, many software bugs which cause crashes are also exploitable
for arbitrary code execution
and other types of privilege escalation
For example, a stack buffer overflow
can overwrite the return address of a subroutine with an invalid value, which will cause, e.g., a segmentation fault
, when the subroutine returns. However, if an exploit overwrites the return address with a valid value, the code in that address will be executed.
When crashes are collected in the field using a crash reporter
, the next step for developers is to be able to reproduce them locally. For this, several techniques exist: STAR uses symbolic execution,
MuCrash mutates the test code of the application that has crashed,
and EvoCrash performs evolutionary search.
- ^ Satvat, Kiavash; Saxena, Nitesh (2018). "Crashing Privacy: An Autopsy of a Web Browser's Leaked Crash Reports". arXiv:1808.01718. Bibcode:2018arXiv180801718S.
- ^ "Analyze Crashes to Find Security Vulnerabilities in Your Apps". Msdn.microsoft.com. 26 April 2007. Retrieved 26 June 2014.
- ^ "Jesse Ruderman » Memory safety bugs in C++ code". Squarefree.com. 1 November 2006. Retrieved 26 June 2014.
- ^ Chen, Ning; Kim, Sunghun (2015). "STAR: Stack Trace Based Automatic Crash Reproduction via Symbolic Execution". IEEE Transactions on Software Engineering. 41 (2): 198–220. doi:10.1109/TSE.2014.2363469. ISSN 0098-5589. S2CID 6299263.
- ^ Xuan, Jifeng; Xie, Xiaoyuan; Monperrus, Martin (2015). "Crash reproduction via test case mutation: let existing test cases help". Proceedings of the 2015 10th Joint Meeting on Foundations of Software Engineering - ESEC/FSE 2015 (PDF). pp. 910–913. doi:10.1145/2786805.2803206. ISBN 9781450336758. S2CID 10358523.
- ^ Soltani, Mozhan; Panichella, Annibale; van Deursen, Arie (2017). "A Guided Genetic Algorithm for Automated Crash Reproduction". 2017 IEEE/ACM 39th International Conference on Software Engineering (ICSE). pp. 209–220. doi:10.1109/ICSE.2017.27. ISBN 978-1-5386-3868-2.
Last edited on 19 April 2021, at 00:56
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