Dmesg Segfault Error Code
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Dmesg Segfault Error 4
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Segfault On Malloc
a community of 4.7 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up Interpreting segfault messages up vote 23 down vote favorite 18 What is the segfault before main correct interpretation of the following segfault messages? segfault at 10 ip 00007f9bebcca90d sp 00007fffb62705f0 error 4 in libQtWebKit.so.4.5.2[7f9beb83a000+f6f000] segfault at 10 ip 00007fa44d78890d sp 00007fff43f6b720 error 4 in libQtWebKit.so.4.5.2[7fa44d2f8000+f6f000] segfault at 11 ip 00007f2b0022acee sp 00007fff368ea610 error 4 in libQtWebKit.so.4.5.2[7f2aff9f7000+f6f000] segfault at 11 ip 00007f24b21adcee sp 00007fff7379ded0 error 4 in libQtWebKit.so.4.5.2[7f24b197a000+f6f000] linux qt webkit kernel segmentation-fault share|improve this question asked Mar 30 '10 at 22:40 knorv 16.1k61172269 possible segfault python duplicate of stackoverflow.com/questions/2179403/… –Charles Duffy Mar 31 '10 at 0:21 add a comment| 3 Answers 3 active oldest votes up vote 43 down vote accepted Hmm. 4 is EINTR (interrupted system call). It may be that libQtWebKit is habitually mishandling that error, or it may be that there's something else that's going on. If this were a program, not a shared library Run addr2line -e yourSegfaultingProgram 00007f9bebcca90d (and repeat for the other instruction pointer values given) to see where the error is happening. Better, get a debug-instrumented build, and reproduce the problem under a debugger such as gdb. Since it's a shared library You're hosed, unfortunately; it's not possible to know where the libraries were placed in memory by the dynamic linker after-the-fact. Reproduce the problem under gdb. What the error means Here's the breakdown of the fields: address (after the at) - the location in memory the code is trying to access (it's likely that 10 and 11 are offsets from a pointer we expect to be set to a valid value but which is instead pointing to 0) ip - instruction pointer, ie. where the code which is trying to do this lives sp - stack pointer error - An error code for page faults; se
segfault) occurs. This can help you debug and understand the bug behind an application crash. Javascript is
Segfault 11
required, please enable it. Error code: Disclaimer: rocket science was linux segfault error 6 not required in the development of this tool. It is based on the error codes
Kernel Segfault Error 4
enum from the linux kernel's arch/x86/mm/fault.c source code file. Email ThisBlogThis!Share to TwitterShare to FacebookShare to Pinterest 1 comment: LittleAncientForestKami24 May 2015 at 03:25No rocket science, http://stackoverflow.com/questions/2549214/interpreting-segfault-messages I agree, yet still a nice idea and realization. Thank you, I just used your tool. Found it via StackOverflow question, if you're curious. ReplyDeleteAdd commentLoad more... Home Subscribe to: Posts (Atom) Popular Posts Explaining segmentation fault errors Editing Debian online with sources.debian.net Debian squeeze LTS Edit Debian, with iceweasel Blog Archive https://rgeissert.blogspot.com/p/segmentation-fault-error.html ▼ 2015 (7) ▼ August (2) Updates to the sources.debian.net editor Call for release goal: package reconsideration ► June (1) ► May (1) ► April (2) ► January (1) ► 2014 (3) ► December (1) ► April (1) ► March (1) ► 2013 (37) ► November (1) ► October (3) ► September (4) ► August (3) ► July (2) ► June (2) ► May (4) ► April (1) ► March (5) ► February (5) ► January (7) ► 2012 (26) ► December (6) ► November (1) ► October (3) ► September (1) ► July (2) ► June (4) ► May (3) ► April (3) ► March (3) Subscribe Posts Atom Posts All Comments Atom All Comments Follow by Email Translate Disclaimer Thoughts and opinions expressed in this blog are my own and not that of my employer or any related party. Copyright 2012, 2013, 2014, 2015 Raphael Geissert. Ethereal template. Powered by Blogger.
to determine from an unprivileged process whether an address residing within the kernel address space is mapped or unmapped. http://vulnfactory.org/blog/2013/02/06/a-linux-memory-trick/ The top-level page fault handler on x86 is do_page_fault(), found in arch/x86/mm/fault.c. When the CPU fires a page fault exception, it pushes an error code onto the stack, https://ubuntuforums.org/showthread.php?t=2010223 which is accessible as an argument to the page fault handler. When a userland process attempts to access unmapped memory or memory whose page permissions do not allow the segfault error desired type of access, the following code path is invoked:
do_page_fault()
__do_page_fault()
bad_area_nosemaphore()
__bad_area_nosemaphore()
show_signal_msg()
This last function prints a message to the kernel syslog with information about the uncaught SIGSEGV that is thrown as a result of the invalid memory access: static inline void show_signal_msg(struct pt_regs *regs, unsigned long error_code, dmesg segfault error unsigned long address, struct task_struct *tsk) { if (!unhandled_signal(tsk, SIGSEGV)) return; if (!printk_ratelimit()) return; printk("%s%s[%d]: segfault at %lx ip %p sp %p error %lx", task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG, tsk->comm, task_pid_nr(tsk), address, (void *)regs->ip, (void *)regs->sp, error_code); print_vma_addr(KERN_CONT " in ", regs->ip); printk(KERN_CONT "\n"); } Note that the error_code printed to the syslog has been passed down all the way from the top-level page fault handler. It's worth taking a look at what the bits of this error code correspond to. Most importantly, bit 0 is the Present flag, indicating whether or not the page the process was trying to access is present at all. Bit 1 is the Read/Write flag, indicating whether this was a read or write fault, and bit 2 is the User/Supervisor flag, which is 0 when the fault was caused by a supervisory process, and 1 if the fault was caused by a user process. In other words, regardless of whether the attempted access resides in user or kernel space, the error code logg
Get Kubuntu Get Xubuntu Get Lubuntu Get UbuntuStudio Get Mythbuntu Get Edubuntu Get Ubuntu-GNOME Get UbuntuKylin Ubuntu Code of Conduct Ubuntu Wiki Community Wiki Other Support Launchpad Answers Ubuntu IRC Support AskUbuntu Official Documentation User Documentation Social Media Facebook Twitter Useful Links Distrowatch Bugs: Ubuntu PPAs: Ubuntu Web Upd8: Ubuntu OMG! Ubuntu Ubuntu Insights Planet Ubuntu Activity Page Please read before SSO login Advanced Search Forum The Ubuntu Forum Community Ubuntu Official Flavours Support General Help [SOLVED] segfaults in some applications, leaving a libc error in dmesg Having an Issue With Posting ? Do you want to help us debug the posting issues ? < is the place to report it, thanks ! Results 1 to 5 of 5 Thread: segfaults in some applications, leaving a libc error in dmesg Thread Tools Show Printable Version Subscribe to this Thread… Display Linear Mode Switch to Hybrid Mode Switch to Threaded Mode June 25th, 2012 #1 hkzlab View Profile View Forum Posts Private Message First Cup of Ubuntu Join Date Jun 2012 Beans 4 segfaults in some applications, leaving a libc error in dmesg Hello everyone, I'm a bit lost on this one, never got something like this in my years of linux experience. Yesterday evening I updated all the packages on my desktop pc (Ubuntu 12.04, amd64, core 2 duo processor) as it was behind a few weeks. Apparently everything went well, the PC powered down fine after I finished. But when I turned it on today I got a nasty surprise: a lot of applications die with a segfault, leaving an error like this in dmesg: Code: [ 185.594356] gimp[3167]: segfault at 7f7c6bc59bf0 ip 00007f7b98eb8fd8 sp 00007fff43d601e8 error 4 in libc-2.15.so[7f7b98d7d000+1b3000] That one is gimp, but I get similar errors with compiz and evolution (the common thing is error 4, libc-2.15.so and the memory offset of 7f7b98d7d000+1b3000). Here is what i tried: Thinking that libc-2.15.so might have gotten corrupt, I reinstalled the libc6 and libc-bin packages directly from the deb files, that didn't helpsuspecting a filesystem corruption, I forced a fsck on boot (/forcefsck). That didn't find anything.suspecting a RAM problem, I ran memtest86 for a few hours. No memory problems at allTo check that my processor was still wo