Bus Error Vs Segmentation Fault
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Segmentation Fault Error In Linux
for the second time it may give a bus error and exit ? c share|improve this question edited May 2 '12 at 12:04 casperOne 58k10126202 asked May 8 '09 at 6:56 Thunderboltz 6253915 add a comment| 6 Answers 6 active oldest votes up vote 34 down vote accepted On most architectures I've used, the distinction is that: a SEGV is caused when you access memory you're not meant to (e.g., outside of your address space). a SIGBUS is caused due to alignment segmentation fault error 139 issues with the CPU (e.g., trying to read a long from an address which isn't a multiple of 4). share|improve this answer answered May 8 '09 at 7:06 paxdiablo 488k1179691416 10 Memory mapped files can also generate SIGBUS. –bk1e May 8 '09 at 16:06 on arm SIGBUS can occur if you read a float from an address that is not 4 byte aligned –shoosh Mar 30 at 7:29 shoosh, I'm pretty certain that's covered by my second bullet point. –paxdiablo Mar 30 at 13:28 add a comment| up vote 11 down vote SIGBUS will also be raised if you mmap() a file and attempt to access part of the mapped buffer that extends past the end of the file, as well as for error conditions such as out of space. If you register a signal handler using sigaction() and you set SA_SIGINFO, it may be possible to have your program examine the faulting memory address and handle only memory mapped file errors. share|improve this answer answered May 8 '09 at 16:04 bk1e 17.9k43760 add a comment| up vote 5 down vote For instance, a bus error might be caused when your program tries to do something that the hardware bus doesn't support. On SPARCs, for instance, trying to read a multi-byte value (such as an int, 32-bits) from an odd address generated a bus error. Segmentation faults happen for instance when you do an access that violate the segmenta
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Bus Error C++
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Bus Error Linux
Answers Thread Tools Search this Thread Display Modes #1 03-28-2008 lakeat Registered User Join Date: Sep 2007 Last Activity: 16 May 2008, 11:01 PM EDT Location: Shanghai Posts: 12 Thanks: 0 http://stackoverflow.com/questions/838540/bus-error-vs-segmentation-fault Thanked 0 Times in 0 Posts What's the difference between Segmentation fault and Bus error and Illegal...? What's the difference between Segmentation fault and Bus error and Illegal instruction? Sometimes I got the one, and sometimes i got another, what are their differences? Segmentation fault (core dump)? Bus error (core dump)? Illegal instruction (core dump) Thanks Daniel Remove advertisements Sponsored Links lakeat View Public Profile Find all posts by lakeat #2 03-28-2008 ajitabhpandey http://www.unix.com/unix-for-dummies-questions-and-answers/58727-whats-difference-between-segmentation-fault-bus-error-illegal.html Registered User Join Date: Mar 2008 Last Activity: 23 October 2012, 11:42 PM EDT Location: Bangalore Posts: 15 Thanks: 0 Thanked 0 Times in 0 Posts Segmentation Fault (also known as SIGSEGV and is usually signal 11) - You can get this message when the program tries to write/read outside the memory allocated for it or when writing memory which can only be read Bus Error (also known as SIGBUS and is usually signal 10) - You can encounter this signal error when an invalid pointer is dereferenced i.e when you try to dereference an uninitialised pointer. It is similar to SIGSEGV but the difference is that SIGSEGV indicates an invalid access to valid memory, while SIGBUS indicates an access to an invalid address. Illegal Instructions (also known as SIGILL and is usually signal 4) - This usually means that your program is trying to execute garbage or a privileged instruction. You might encounter this - (a.) when you try to execute data (b.) when you try to execute a corrupted executed file. (c.) stack overflows (d.) when the system has trouble running the handler for a signal HTH Remove advertisements Sponsored Links ajitabhpandey View Public Profile Visit ajitabhpandey's homepage! Find all posts by ajitabhpandey #3 03-28-2008 lakeat Registered User Join Date: Sep 2007 Last Activity: 16 M
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, https://en.wikipedia.org/wiki/Bus_error notifying an operating system (OS) that a process is trying to access memory that the CPU cannot physically address: an invalid address for the address bus, hence the name. In modern use on most architectures these are much rarer than segmentation faults, which occur primarily due to memory access violations: problems in the logical address or permissions. segmentation fault 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 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 segmentation fault error 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 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 C