I'm on a VirtualBox with Ubuntu 18.10 installed on, and I'm new using it. My code creates 100 forked child that works on a shared memory. SOMETIME I get this message
Sender(Pid = (childPID)) terminated with status 0x008B.
Searching in the web I found that could be a SIGSEGV error. Is it true?
Finally, is there any way to find WHERE the code fails in over 1000 lines? I tryed using this Guide: http://www.unknownroad.com/rtfm/gdbtut/gdbsegfault.html to find the error with gdb but my terminal says me that I have "No Stack". I'm totally new with this kind of problems, any hint will be appreciated.
Sender(Pid = (childPID)) terminated with status 0x008B.
Searching in the web I found that could be a SIGSEGV error. Is it true?
Yes, that indicates termination by signal 11 (0xB).
Finally, is there any way to find WHERE the code fails in over 1000 lines?
I'd run the program with valgrind.
Related
I had a program that was segfaulting.
When I went to investigate and ran dmesg I could see lines like this:
[955.915050] traps: foo_bar[123] general protection ip:7f5fcc2d4306 sp:7ffd9e5868b8 ...
Now the program has been fixed and I'm trying to write some analysis scripts across different systems to find similar messages and was hoping to induce a line in the dmesg log to get a baseline for what to look for and see if there's a difference between, say, a sigbus(10) and a sigill(4)
I tried to do it via kill -11 on the command line . No entry in dmesg
I tried to do it via signal(getpid(), 11) in the code. No entry in dmesg
I tried to do it via signal 11 after attaching in gdb . No entry in dmesg
I tried to do it via writing bad code and it worked for SEGV, but I can't figure out how to trigger a SIGBUS (for example)
I'm guessing that there is more than one path for handling the signal depending on how it occurs and my attempts above just aren't doing it the right way.
How can I trigger/send a signal to my program that'll get a line in dmesg? Is there some kernel or log configuration I can twiddle to get those lines?
Update:
" __builtin_trap: when to use it? " shows how to get a SIGILL but alas doesn't have a signal-agnostic solution)
I want to use p3dfft first NxNxN and in-between 2Nx2Nx2N dimensions. I have tried to implement that, it shows
P3DFFT Setup error: the problem is already initialized.
Currently multiple setups not supported.
Quit the library using p3dfft_clean before initializing another setup
or if I tried to set up p3dfft 2 times (without cleaning first one) it shows error code 139. See below,
===================================================================================
= BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES
= PID 4127 RUNNING AT localhost.localdomain
= EXIT CODE: 139
= CLEANING UP REMAINING PROCESSES
= YOU CAN IGNORE THE BELOW CLEANUP MESSAGES
===================================================================================
YOUR APPLICATION TERMINATED WITH THE EXIT STRING: Segmentation fault (signal 11)
This typically refers to a problem with your application.
Please see the FAQ page for debugging suggestions
I was trying to making header file and made one function for given dimension but still error is there when function called 2 times for 2 different dimensions.
I'm trying to figure out why an WPF-app won't exit imediately on closing it. Using Process Explorer I hade found out that WerFault.exe is started while exiting which seem to indicate that something crashes during the teardown, perhaps some destructor or dispose that fails. This started happening when I recently switched to VS2015. I am running Windows 8.
My question is: How can I find out what the real problem is? Any way of finding a crash log for WerFault.exe? I have hundreds of destructors and dispose-methods so it's a bit hard to put breakpoints in all of them. Any other way of capturing these kinds of errors in VS?
The exit code is -1073740791 which "indicate a bug in the executed software that causes stack overflow, leading to abnormal termination of the software". But where?
Some more info from the event log:
Faulting module name: ucrtbase.DLL, version: 10.0.10240.16390, time stamp: 0x55a5b718
Exception code: 0xc0000409
Fault offset: 0x0000000000065a4e
You could try enabling user mode dumps:
Create the registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Windows Error Reporting\LocalDumps
Within LocalDumps, create a key that is the name of your executable
Within the key you just created, set the values of DumpFolder, DumpCount, DumpType, and CustomDumpFlags as needed (you should definitely set DumpType to 2 for full dumps, otherwise I don't think that enough information will be captured to debug a managed dump).
Once you have done this, whenever your executable crashes a dump file will be created in the folder specified by DumpFolder (or %LOCALAPPDATA%\CrashDumps by default).
I am new in C programming and I have been trying hard to customize an opensource tool written in C according to my organizational needs.
IDE: Eclipse,
Debugger: GDB,
OS: RHEL
The tool is multi-process in nature (main process executes first time and spawns several child processes using fork() ) and they share values in run time.
While debugging in Eclipse (using GDB), I find that the process being debugged is only running while other processes are in suspended mode. Thus, the only running process is not able to do its intended job because the other processes are suspended.
I saw somewhere that using MI command in GDB as "set non-stop on" could make other processes running. I used the same command in the gdbinit file shown below:
Note: I have overridden above .gdbinit file with an another gdbinit because the .gdbinit is not letting me to debug child processes as debugger terminates after the execution of main process.
But unfortunately debugger stops responding after using this command.
Please see below commands I am using in the gdbinit file:
Commenting non-stop enables Eclipse to continue usual debugging of the current process.
Adding: You can see in below image that only one process is running while others are suspended.
Can anyone please help me to configure GDB according to my requirement?
Thanks in advance.
OK #n.m.: Actually, You were right. I should have given more time to understand the flow of the code.
The tool creates 3 processes first and then the third process creates 5 threads and keeps on wait() for any child thread to terminate.
Top 5 threads (highlighted in blue) shown in the below image are threads and they are children of Process ID: 17991
The first two processes are intended to initiate basic functionality of the tool and hence they just wait to get exit(0). You can see below.
if (0 != (pid = zbx_fork()))
exit(0);
setsid();
signal(SIGHUP, SIG_IGN);
if (0 != (pid = zbx_fork()))
exit(0);
That was the reason I was not actually able to step in these 3 processes. Whenever, I tried to do so, the whole main process terminated immediately and consequently leaded to terminate all other processes.
So, I learned that I was supposed to "step-into" threads only. And yes, actually I can now debug :)
And this could be achieved because I had to remove the MI command "set follow-fork-mode child". So, I just used the default " .gdbinit" file with enabled "Automatically debug forked process".
Thanks everyone for your input. Stackoverflow is an awesome place to learn and share. :)
if((sem_init(sem, 1, 1)) == 1) perror("error initiating sem");
If I include this line of code my program simply starts and exits. I just started learning how to use semaphores. I'm using cygwin and when this line is commented out the printf's ABOVE this print to console but when include this, nothing happens.
I did the following to get cygserver going-
CYGWIN=server
ran /bin/cygserver-config
ran /usr/sbin/cygserver
for the config it said the cygserver is already running
And for the sygserver it saids-
initailaizing complete
failed to created named pipe: is the daemon already running?
fatal error on IPC transport: closing down
Any ideas?
I figured out what was wrong. I was using data(struct) = shmat() before I was assigning any memory to data. That for some reason was stopping my 'printf' from working.