Linux Signal Bus Error
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Linux Bus Error Core Dumped
it only takes a minute: Sign up What is a bus error? up vote 156 down vote favorite 49 What does the "bus error" message mean, and how does it differ from a segfault? c unix segmentation-fault bus-error share|improve this
How To Solve Bus Error In Linux
question edited Oct 18 '15 at 10:44 Cool Guy 15.7k51952 asked Oct 17 '08 at 14:48 raldi 7,272216178 add a comment| 15 Answers 15 active oldest votes up vote 151 down vote accepted Bus errors are rare nowadays on x86 and occur when your processor cannot even attempt the memory access requested, typically: using a processor instruction with an address that does not satisfy its alignment requirements. Segmentation faults occur when accessing memory which does not belong to your how to debug bus error process, they are very common and are typically the result of: using a pointer to something that was deallocated. using an uninitialized hence bogus pointer. using a null pointer. overflowing a buffer. PS: To be more precise this is not manipulating the pointer itself that will cause issues, it's accessing the memory it points to (dereferencing). share|improve this answer edited Oct 17 '08 at 15:18 answered Oct 17 '08 at 15:12 bltxd 5,72322336 52 They aren't rare; I'm just at Exercise 9 from How to Learn C the Hard Way and already encountered one... –11684 Mar 26 '13 at 20:12 5 Another cause of bus errors (on Linux anyway) is when the operating system can't back a virtual page with physical memory (e.g. low-memory conditions or out of huge pages when using huge page memory.) Typically mmap (and malloc) just reserve the virtual address space, and the kernel assigns the physical memory on demand (so called soft page faults.) Make a large enough malloc, and then write to enough of it and you'll get a bus error. –Eloff Jul 14 '15 at 0:09 add a comment| up vote 58 down vote A segfault is accessing memory that you're not allowed to access. It's read-only, you don't have permission, etc... A bus error is trying to access memory that can't possibly be there. You've used an address that's meaningless to the system, or the wrong kin
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Bus Error Vs Segmentation Fault
Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is sigbus error linux a community of 6.2 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up How to get a “bus bus error ubuntu error”? up vote 12 down vote favorite 1 I am trying very hard to get a bus error. One way is misaligned access and I have tried the examples given here and here, but no error for me - the programs execute just http://stackoverflow.com/questions/212466/what-is-a-bus-error fine. Is there some situation which is sure to produce a bus error? c++ bus-error share|improve this question edited Jan 15 '10 at 9:50 asked Jan 15 '10 at 4:06 Lazer 25.1k66212310 2 What platform and hardware architecture are you using? –R Samuel Klatchko Jan 15 '10 at 5:32 it should be noted that by default x86 will not have a bus error, instead it will work but the memory access will be not as performant as an aligned read. on the other hand SPARC http://stackoverflow.com/questions/2069450/how-to-get-a-bus-error arches do have a bus error. –Evan Teran Jan 15 '10 at 6:50 1 No, see Michael Burr's comments and my answer. Even on x86, you can get a bus error by attempting to access memory which does not exist (as opposed to a segmentation fault, which comes from a violation of access policy). –ephemient Jan 16 '10 at 16:29 add a comment| 11 Answers 11 active oldest votes up vote 11 down vote accepted Bus errors can only be invoked on hardware platforms that: Require aligned access, and Don't compensate for an unaligned access by performing two aligned accesses and combining the results. You probably do not have access to such a system. share|improve this answer answered Jan 15 '10 at 4:09 Ignacio Vazquez-Abrams 446k64798955 is there some way to be sure of that? –Lazer Jan 15 '10 at 4:11 @eSKay: If you're using an Intel CPU, which means basically any personal computer nowadays, you will never get a bus error from misaligned access. If you're using PowerPC, SPARC, etc., then you can cause a bus error that way. –Chris Jester-Young Jan 15 '10 at 4:13 2 Do you have any SPARC or MIPS equipment? –Ignacio Vazquez-Abrams Jan 15 '10 at 4:13 yes, I am using Intel P4. Any idea why no error on Intels? –Lazer Jan 15 '10 at 4:14 3 There are typically other ways a bus error can occur than just unaligned memory access. It's very platform specific as to what causes a bus error (or
& Answers This forum is closed for new posts. Please post beginner questions to learn unix and learn linux in this forum UNIX for Beginners Questions & Answers Search http://www.unix.com/unix-for-dummies-questions-and-answers/3109-bus-error.html Forums Show Threads Show Posts Tag Search Advanced Search Unanswered Threads Find All Thanked Posts Go to Page... learn unix and linux commands Bus Error UNIX for Dummies Questions & Answers http://www.gnu.org/s/libc/manual/html_node/Program-Error-Signals.html Thread Tools Search this Thread Display Modes #1 11-09-2001 LivinFree Goober Extraordinaire Join Date: Jul 2001 Last Activity: 16 June 2011, 4:50 PM EDT Location: Portland, OR, USA Posts: 1,626 bus error Thanks: 2 Thanked 15 Times in 13 Posts Bus Error This may belong in the C Programming forum, but here goes anyway... What would cause a bus error? I searched google for a cause, but came up with some conflicting reports... Could it be caused by [lack of] disk space? A lot of the pages I found mentioned linking with the incorrect versions of the library. But in that bus error linux case, would it compile correctly? Basically, I am curious as to why we had a job dump core on a bus error. It ran nearly to normal completion time, then simply poo-pood. In the case that it may make a difference, it's a job that interfaces with an Oracle database on HP-UX 11. The things that had changed were that the process was recompiled, AND we were at 96% (df -k) on that disk... Not too important for me to know right now, but I am curious, and who wants to wait for developers to tell me what happened? Remove advertisements Sponsored Links LivinFree View Public Profile Find all posts by LivinFree #2 11-09-2001 Perderabo Unix Daemon (Administrator Emeritus) Join Date: Aug 2001 Last Activity: 26 February 2016, 12:31 PM EST Location: Ashburn, Virginia Posts: 9,931 Thanks: 64 Thanked 462 Times in 267 Posts The bus in question is the address buss and it contains an illegal value. This is almost always the result of dereferencing a pointer that contains an illegal value. Here is a program that, I think, will compile with every C or C++ compiler, but should cause a bus error when the second printf is attempted... Code: #ifdef __STDC
of these signals are indications that your program is seriously broken in some way, and there’s usually no way to continue the computation which encountered the error. Some programs handle program error signals in order to tidy up before terminating; for example, programs that turn off echoing of terminal input should handle program error signals in order to turn echoing back on. The handler should end by specifying the default action for the signal that happened and then reraising it; this will cause the program to terminate with that signal, as if it had not had a handler. (See Termination in Handler.) Termination is the sensible ultimate outcome from a program error in most programs. However, programming systems such as Lisp that can load compiled user programs might need to keep executing even if a user program incurs an error. These programs have handlers which use longjmp to return control to the command level. The default action for all of these signals is to cause the process to terminate. If you block or ignore these signals or establish handlers for them that return normally, your program will probably break horribly when such signals happen, unless they are generated by raise or kill instead of a real error. When one of these program error signals terminates a process, it also writes a core dump file which records the state of the process at the time of termination. The core dump file is named core and is written in whichever directory is current in the process at the time. (On GNU/Hurd systems, you can specify the file name for core dumps with the environment variable COREFILE.) The purpose of core dump files is so that you can examine them with a debugger to investigate what caused the error. Macro: int SIGFPE The SIGFPE signal reports a fatal arithmetic error. Although the name is derived from “floating-point exception”, this signal actually covers all arithmetic errors, including division by zero and overflow. If a program stores int