Bus Error Bad Memory Access
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Bus Error In Linux
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How To Debug Bus Error
Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up Debugging SIGBUS on x86 Linux up vote 9 down vote bus error (core dumped) c favorite 2 What can cause SIGBUS (bus error) on a generic x86 userland application in Linux? All of the discussion I've been able to find online is regarding memory alignment errors, which from what I understand doesn't really apply to x86. (My code is running on a Geode, in case there are any relevant processor-specific quirks there.) linux debugging bus-error sigbus share|improve this question asked Jan 18 '10 at how to solve bus error in linux 20:58 Josh Kelley 34.3k1273147 add a comment| 6 Answers 6 active oldest votes up vote 12 down vote accepted You can get a SIGBUS from an unaligned access if you turn on the unaligned access trap, but normally that's off on an x86. You can also get it from accessing a memory mapped device if there's an error of some kind. Your best bet is using a debugger to identify the faulting instruction (SIGBUS is synchronous), and trying to see what it was trying to do. share|improve this answer answered Jan 18 '10 at 21:10 Chris Dodd 2,274710 1 The debugger showed that the SIGBUS occurred immediately upon entering the function. Maybe I have some memory corruption, or maybe one of the function parameters is bad? I'll have to check the disassembly in the debugger for more details if the error occurs again. –Josh Kelley Jan 18 '10 at 22:13 1 @Josh -- check to see what the actual failing instruction is -- if its a push or pop, then your stack pointer is corrupted. If its something else, then the address in the instruction is the issue. –Chris Dodd Jan 19 '10 at 19:04 add a comment| up vote 1
challenged and removed. (July 2015) (Learn how and when to remove this template message) In computing, a bus error is a fault raised by hardware, notifying an operating system (OS) that a process is trying to access memory
Sigbus Error Linux
that the CPU cannot physically address: an invalid address for the address bus, bus error core dumped c++ hence the name. In modern use on most architectures these are much rarer than segmentation faults, which occur primarily due to
Bus Error (core Dumped) Ubuntu
memory access violations: problems in the logical address or permissions. On POSIX-compliant platforms, bus errors usually result in the SIGBUS signal being sent to the process that caused the error. SIGBUS can also be caused http://stackoverflow.com/questions/2089167/debugging-sigbus-on-x86-linux by any general device fault that the computer detects, though a bus error rarely means that the computer hardware is physically broken—it is normally caused by a bug in a program's source code.[citation needed] Bus errors may also be raised for certain other paging errors; see below. Contents 1 Causes 1.1 Non-existent address 1.2 Unaligned access 1.3 Paging errors 2 Example 3 References Causes[edit] There are at least three main https://en.wikipedia.org/wiki/Bus_error causes of bus errors: Non-existent address[edit] Software instructs the CPU to read or write a specific physical memory address. Accordingly, the CPU sets this physical address on its address bus and requests all other hardware connected to the CPU to respond with the results, if they answer for this specific address. If no other hardware responds, the CPU raises an exception, stating that the requested physical address is unrecognized by the whole computer system. Note that this only covers physical memory addresses. Trying to access an undefined virtual memory address is generally considered to be a segmentation fault rather than a bus error, though if the MMU is separate, the processor can't tell the difference. Unaligned access[edit] Most CPUs are byte-addressable, where each unique memory address refers to an 8-bit byte. Most CPUs can access individual bytes from each memory address, but they generally cannot access larger units (16 bits, 32 bits, 64 bits and so on) without these units being "aligned" to a specific boundary (the x86 platform being a notable exception). For example, if multi-byte accesses must be 16 bit-aligned, addresses (given in bytes) at 0, 2, 4, 6, and so on would be considered aligned and therefore accessible, while addresses 1, 3, 5, an
& 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 Forums http://www.unix.com/unix-for-dummies-questions-and-answers/3109-bus-error.html Show Threads Show Posts Tag Search Advanced Search Unanswered Threads Find All Thanked Posts Go to Page... linux operating commands and unix operating commands Bus Error UNIX for Dummies Questions & Answers 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: bus error 1,626 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 (core 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__ #def