Category Archives: How to Fix

Waitpid call return error prompt: no child processes problem

The problem
An error occurred in a function today with a probabilistic waitpid call. The error is No child processes. The prompt does not have this child process, the PID number can also be wrong, so add the print, when the duplicate found that the PID number can correspond to, no problem.
online, found “No child” the processes of error code corresponding ECHILD, waitpid there is in man’s document, if the process set the SIGCHLD signal processing to SIG_IGN, then the call will return ECHILD waitpid.
to see the code, the parent process does have to capture the SIGCHLD signal inside, for processing way

rc = waitpid(-1, &status, WNOHANG);

Wait for any child process to exit so that it can be recovered. I suspect that calling WaitPid again when the parent process has already collected its body will be an error. And that explains the probabilistic problem. So write the following code to verify it.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>

void sig_handle(int sig)
{
    waitpid(-1, NULL, 0);
    printf("llm->%s(%d)\n", __FUNCTION__, __LINE__);
}

int main(int argc, char *argv[])
{
    int rtn = 0;
    int pid = 0;
    char *arg[] = {"date", NULL};
    signal(SIGCHLD, sig_handle);
    //signal(SIGCHLD, SIG_IGN);

    while(1)
    {
        pid = fork();
        if(!pid)
        {
            execvp("date", arg);
            exit(1);
        }
        usleep(10*1000);
        rtn = waitpid(pid, NULL, 0);

        if(rtn < 0)
            perror("waitpid");
        //usleep(10*1000);
    }
    return 0;
}

If you add sleep before waitpid, the problem will be 100% duplicated. If you remove sleep, there will be no problem.
The solution
Given the current code logic, there is a problem with either Waitpid being removed, so the best course of action is to determine whether it is true or false. If Waitpid returns ECHILD, then ignore the error.
The system calls
This is not a problem with the system call. This is not a problem with the implementation of waitpid after fork. The implementation handles the signal accordingly. The SIGCHLD signal processing action is restored before fork, as follows:

int __libc_system(char *command)
{
	int wait_val, pid;
	__sighandler_t save_quit, save_int, save_chld;

	if (command == 0)
		return 1;

	save_quit = signal(SIGQUIT, SIG_IGN);
	save_int = signal(SIGINT, SIG_IGN);
	save_chld = signal(SIGCHLD, SIG_DFL);

	if ((pid = vfork()) < 0) {
		signal(SIGQUIT, save_quit);
		signal(SIGINT, save_int);
		signal(SIGCHLD, save_chld);
		return -1;
	}
	if (pid == 0) {
		signal(SIGQUIT, SIG_DFL);
		signal(SIGINT, SIG_DFL);
		signal(SIGCHLD, SIG_DFL);

		execl("/bin/sh", "sh", "-c", command, (char *) 0);
		_exit(127);
	}
	/* Signals are not absolutly guarenteed with vfork */
	signal(SIGQUIT, SIG_IGN);
	signal(SIGINT, SIG_IGN);

#if 0
	printf("Waiting for child %d\n", pid);
#endif

	if (wait4(pid, &wait_val, 0, 0) == -1)
		wait_val = -1;

	signal(SIGQUIT, save_quit);
	signal(SIGINT, save_int);
	signal(SIGCHLD, save_chld);
	return wait_val;
}
weak_alias(__libc_system, system)

Git bash display error can not be used, how to solve

Solution:
It seems that the 64-bit version will have problems, but 32-bit Git can also be installed on 64-bit systems.
Once you have unloaded your 64-bit Git installation, download a 32-bit Git installation and you will be able to use it normally.
Of course, your 32-bit error, unloaded after the same process, install 64-bit, this will not be a problem, but 32-bit more stable.

Reproduced in: https://www.cnblogs.com/flxy-1028/p/6922987.html

Resolve – bash: fork: Retail: resource temporarily unavailable error

1. If -bash: fork: retry: Resource error is unavailable, then you have no further questions. If the maximum number of Linux processes is exceeded, then change the maximum number of Linux processes.

Connect to the server using the CRT connection tool

[support@localhost ~]$ ulimit -a
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 127405
max locked memory       (kbytes, -l) 64
max memory size         (kbytes, -m) unlimited
open files                      (-n) 1024
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 10240
cpu time               (seconds, -t) unlimited
max user processes              (-u) 1024
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited
[support@localhost ~]$

You can’t switch root after logging in, even if you type the clear command, you will get an error.
online said it could open too many processes, the system allows you to create the maximum number of processes Max user the processes the parameters.
> Max user processes can use ulimit-u 4096, but only in the session of the current terminal. The default values will be used once you log in again. So it can’t be used.
the right way to change is to modify the/etc/security/limits. D/90 – nproc. The values in the conf file. CD/etc/securit/lims.d/
: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 

# Default limit for number of user's processes to prevent
# accidental fork bombs.
# See rhbz #432903 for reasoning.

*          soft    nproc     4096
root       soft    nproc     unlimited

You can change the value, but note that root is used for the change, and no other user has permission by default.
because they have no root, he found a can be resource-intensive process, users can connect.
On the Internet to see the number of connections command
ps – the eLf | grep username, check the progress of the target user.
Reference links: http://www.nginx.cn/3002.html
https://zhidao.baidu.com/question/1640745287732090500.html

Git bash run error, GIT 32 bit

Environment:
Win10 64-bit
Error: Could not fork child process: Resource Error is unavailable (-1).
l rebasing may be required; See ‘rebaseAll/rebase — help’.
: failed to fork child process no such file or directory, DLL rebasing may be required
Solutions:
1. Go to the Git installation directory and run git-cmd.exe;
>
>
>
>
> rebase-b 0x76000000…
rebase-b 0x76000000… /msys-2.0.dll
/msys-2.0.dll
/msys-2.0.dll
/msys-2.0.dll
/msys-2.0.dll
/msys-2.0.dll
/msys-2.0.dll
/msys-2.0.dll. Copy msys-2.0.dll back to /bin current directory (.. Represents the current directory)
Rerun git-bash.exe, problem solved!

Git bash error, version 2.16.2-64-bit

Environment: Win7 64-bit
Error: Could not fork child process: Resource temporarily unavailable (-1).
DLL rebasing may be required; See ‘rebaseAll/rebase — help’.
 
Failed to fork child process no such file or directory, DLL rebasing may be required
 
Solutions:
1. Go to the Git installation directory and run git-cmd.exe;
2, Execution command: CD usr/bin, enter /bin directory;
3, Execute command: CP MSYS-2.0. DLL.. /, copy msys-2.0.dll to the directory above;
Rebase-b 0x76000000… rebase-b 0x76000000…/msys – 2.0. DLL
Rebase-b 0x30000000… rebase-b 0x30000000…/msys – 2.0. DLL
6, Execute command: cp.. /msys-2.0.dll. Copy msys-2.0.dll back to /bin current directory (.. Represents the current directory)
 
Rerun git-bash.exe, problem solved!
 
If the problem persists, try modifying the registry:
1. Open Run and type regedit to open the registry
[HKEY_CLASSES_ROOT \ DIRECTORY \ BACKGROUND \ SHELL \ GIT_SHELL \ COMMAND] :\Program Files\Git\git-bash.exe
3, Replace it with C: Program Files\Git\bin\sh.exe
 
 
 

Error:could not fork child process: There are no available terminals (-1).

Git Bash terminal cannot be opened

1, in the CMD command input tasklist check git – bash. Exe process, find the corresponding process pid
no. 2, tasklist | findstr searches process, pid # find process, the corresponding process
no. 3, taskkill/pid process pid – t – f # is corresponding process termination command, after the termination, can open the git bash terminal
If that still doesn’t work, restart your computer
 
 
 
 
 
 
 
 

Git bash here running error: failed to fork child process

The following error occurs when you run Git Bash Here…

Git bash here Failed to fork child process: No such file or directory

The Git version is 2.9.3, and reinstalling different versions of Git does not solve this problem

Solution:
Step 1: Find the Git installation directory on your computer
Step 2: Enter the directory –>; user –> Bin, locate the msys-2.0.dll file
Step 3: Copy msys-2.0.dll to a directory
Step 3: Open the CMD command in the bin file (Shift + mouse right-click –>; Open the command window here), and run the command
Rebase – 0 x76000000 b… \ msys – 2.0. DLL
Rebase – 0 x30000000 b… \ msys – 2.0. DLL
Step 4: Replace the DLL under the bin file with the MSYS-2.0.dll copied in the third step

glassfish:Resource temporarily unavailable in tsStartJavaThread

Today the test server (using glassfish3.1.1) suddenly reported the following exception while deploying the application. -bash: fork: retry: Resource permanently unavailable. If you have no further questions, then you have no further questions.

[ERROR] [ERROR][thread ] Could not start thread Keep-Alive-Timer. Resource temporarily unavailable
[ERROR] Exception in thread "Main Thread" java.lang.OutOfMemoryError: Resource temporarily unavailable in tsStartJavaThread (lifecycle.c:1096).
[ERROR] Java heap 3G reserved, 64M committed
[ERROR] Paged memory=18014398505034060K/18389412K.
[ERROR] Your Java heap size might be set too high.
[ERROR] Try to reduce the Java heap size using -Xmx:<size> (e.g. "
[ERROR]         at java.lang.Thread.start0(Native Method)
[ERROR]         at java.lang.Thread.start(Thread.java:597)
[ERROR]         at sun.net.www.http.KeepAliveCache$1.run(KeepAliveCache.java:89)
[ERROR]         at sun.net.www.http.KeepAliveCache.put(KeepAliveCache.java:75)
[ERROR]         at sun.net.www.http.HttpClient.putInKeepAliveCache(HttpClient.java:370)
[ERROR]         at sun.net.www.http.HttpClient.finished(HttpClient.java:358)
[ERROR]         at sun.net.www.http.ChunkedInputStream.closeUnderlying(ChunkedInputStream.java:196)
[ERROR]         at sun.net.www.http.ChunkedInputStream.processRaw(ChunkedInputStream.java:428)
[ERROR]         at sun.net.www.http.ChunkedInputStream.readAheadNonBlocking(ChunkedInputStream.java:493)
[ERROR]         at sun.net.www.http.ChunkedInputStream.readAhead(ChunkedInputStream.java:584)
[ERROR]         at sun.net.www.http.ChunkedInputStream.available(ChunkedInputStream.java:698)
[ERROR]         at java.io.FilterInputStream.available(FilterInputStream.java:142)
[ERROR]         at java.nio.channels.Channels$ReadableByteChannelImpl.read(Channels.java:196)
[ERROR]         at com.sun.enterprise.util.io.FileUtils.copy(FileUtils.java:915)
[ERROR]         at com.sun.enterprise.admin.remote.RemoteResponseManager.<init>(RemoteResponseManager.java:79)
[ERROR]         at com.sun.enterprise.admin.remote.RemoteAdminCommand.handleResponse(RemoteAdminCommand.java:1056)
[ERROR]         at com.sun.enterprise.admin.remote.RemoteAdminCommand.handleResponse(RemoteAdminCommand.java:1045)
[ERROR]         at com.sun.enterprise.admin.remote.RemoteAdminCommand.access$600(RemoteAdminCommand.java:101)
[ERROR]         at com.sun.enterprise.admin.remote.RemoteAdminCommand$1$1.handleReport(RemoteAdminCommand.java:526)
[ERROR]         at org.glassfish.admin.payload.PayloadFilesManager.processReport(PayloadFilesManager.java:473)
[ERROR]         at org.glassfish.admin.payload.PayloadFilesManager.access$900(PayloadFilesManager.java:93)
[ERROR]         at org.glassfish.admin.payload.PayloadFilesManager$DataRequestType$4.processPart(PayloadFilesManager.java:776)
[ERROR]         at org.glassfish.admin.payload.PayloadFilesManager.processPartsExtended(PayloadFilesManager.java:624)
[ERROR]         at org.glassfish.admin.payload.PayloadFilesManager.processParts(PayloadFilesManager.java:643)
[ERROR]         at com.sun.enterprise.admin.remote.RemoteAdminCommand$1.useConnection(RemoteAdminCommand.java:531)
[ERROR]         at com.sun.enterprise.admin.remote.RemoteAdminCommand.doHttpCommand(RemoteAdminCommand.java:700)
[ERROR]         at com.sun.enterprise.admin.remote.RemoteAdminCommand.doHttpCommand(RemoteAdminCommand.java:543)
[ERROR]         at com.sun.enterprise.admin.remote.RemoteAdminCommand.executeRemoteCommand(RemoteAdminCommand.java:482)
[ERROR]         at com.sun.enterprise.admin.remote.RemoteAdminCommand.executeCommand(RemoteAdminCommand.java:419)
[ERROR]         at com.sun.enterprise.admin.cli.remote.RemoteCommand.executeCommand(RemoteCommand.java:335)
[ERROR]         at com.sun.enterprise.admin.cli.CLICommand.execute(CLICommand.java:264)
[ERROR]         at com.sun.enterprise.admin.cli.AsadminMain.executeCommand(AsadminMain.java:306)
[ERROR]         at com.sun.enterprise.admin.cli.AsadminMain.main(AsadminMain.java:238)
[ERROR] [ERROR][thread ] Could not start thread Thread-0. Resource temporarily unavailable
[ERROR] Deployment of /home/javadev/codes/*****************.war failed.
[ERROR] For more detail on what might be causing the problem try running maven with the --debug option 
[ERROR] or setting the maven-glassfish-plugin "echo" property to "true".

We first analyzed the abnormal, see “Paged memory = 18014398505034060 k/18389412 k.” immediately startled, thought who is boring and the change of configuration information. Looking at the configuration parameters for the GlassFish startup JVM in the GlassFish console, I found nothing unusual and nothing changed compared to the other configurations. The same configuration worked well on the other test servers, initially eliminating GlassFish and JVM parameter configuration issues.
= “-bash: fork: retry: Resource permanently” (check the number of processes :

 [javadev@snaqi-test3 ~]$ ps -ef|wc -l
 1025

But in the/etc/security/limits the conf javadev user configuration

    javadev             soft    nproc   1024
    javadev             hard    nproc   16384
    javadev             soft    nofile  2048
    javadev             hard    nofile  65536

Obviously the number of user processes has reached the limit of the limit. Change line 1 from 1024 to 2048. Problem solved. In addition, the third line 2048 can be enlarged to prevent the “too many file litres” of the program.

Su prompt when switching users: resource temporarily unavailable

I failed to connect the FTP server authentication with WinSCP today. I felt really strange. Nothing has been moved and everything was normal before.
If I su to FTP user, I keep saying “-bash:fork:Resource permanently unavailable”. If I have no further questions, I have no further questions. If I su to FTP user, I have no further questions.
[root@cls vsftpd]# su bupdate
bash: fork: retry: Resource temporarily unavailable
bash: fork: retry: Resource temporarily unavailable
bash: fork: retry: Resource temporarily unavailable
bash: fork: retry: Resource temporarily unavailable
^C
1, first check the disk, memory are OK
[bupdate@cls vsftpd]$ top
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
32141 bupdate 20 0 16296 2548 1004 R 2.3 0.1 0:00.61 top
root 20 0 19272 1576 1312 S 0.0 0.0 0:06. 43 init
2 root 20 0 0 0 0 S 0.0 0.0 0:00. 00 kthreadd
root RT 3 0 0 0 0 S 0.0 0.0 0:01.45 migration/0
4 root 20 00 0 S 0.0 0.0 0:00.12 ksoftirqd/0
root RT 00 0 S 0.0 0.0 0:00.00 migration/0
6 root RT 0 0 0 0 S 0.0 0.0 0:00. 00 watchdog/0
7 root RT 0 0 0 0 S 0.0 0.0 0:02. 26 migration/1
root RT 8 0 00 0 0 0 S 0.0 0.0 0:00. The migration/1
9 root 20 0 0 0 0 S 0.0 0.0 0:00. 25 ksoftirqd/1
10 root RT 0 0 0 0 S 0.0 0.0 0:27. 92 watchdog/1
11 root RT 0 0 0 0 S 0.0 0.0 0:00. 92 migration/2
12 root RT 0 0 0 0 S 0.0 0.0 0:00. 00 migration/2
13 root 20 0 0 0 0 S 0.0 0.0 0:00. 01 ksoftirqd/2

2. Use ulimit-a to get the result

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    the core file size (data blocks, -c) 0 seg size (kbytes, -d) unlimited Max nice (-e) 0, the file size (blocks, -f) is unlimited Pending signals (-i) 71679 Max locked memory (in kbytes, -l) 32 Max memory size (kbytes, -m) unlimited open files (-n) 1024 Pipe size (512 bytes, the -p) 8 POSIX message the queues (bytes, – q) 819200 Max rt priority (-r) 0 stack size (10240 kbytes, -s) CPU time (seconds, -t) unlimited Max user the processes (-u) 2047 virtual memory (in kbytes, -v) unlimited file locks (-x) unlimited

     
    3, modify the/etc/security/limits. Conf

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    The

      * soft nproc 2047 * hard nproc 16384

      limits. Conf format:

      username | @ groupname type resource limit
      The username | @ groupname: Settings need to be restricted user name, add @ in front of the group name and user name. You can also limit all users with a wildcard *.
      Type: soft, hard and -, soft refers to the current system in effect. Hard indicates the maximum value that can be set in the system. The maximum value of soft cannot exceed the value of hard. Using – indicates that both soft and hard values are set.
      The resource:
      the core – limit the size of the kernel file
      the date – the largest data size
      fsize – maximum file size
      memlock – largest lock memory address space
      nofiles – the maximum number of open file
      RSS – maximum persistent set size
      stack – stack size
      maximum CPU – units of minutes up CPU time
      noproc – process the maximum number of
      the as – Address space limit
      maxlogins – the maximum number of logins allowed by this user
      For the lims.conf file configuration to take effect, you must ensure that the pam_lims.so file is added to the startup file.
      session required /lib/security/pam_limits. So.
      session required /lib/security/pam_limits
       
      4. Or modify the /etc/profile file
      Ulimit [- acdfHlmnpsStvw] [size]
      Parameter details:

      -a>
      size: Sets the maximum value of the core file.
      -c size: Sets the maximum value of the core file. Blocks
      -d Size: Sets the maximum number of blocks in the data segment.
      -f size: Set the maximum value of the file to create. Blocks
      -l Size: Sets the maximum number of processes locked in memory.
      -m Size: Sets the maximum amount of resident memory that can be used. Kbytes
      -n Size: Sets the maximum number of file descriptors that the kernel can open at the same time. N
      -p Size: Sets the maximum value of the pipeline buffer.
      -s size: Sets the maximum value of the stack.
      -t size: Set the maximum CPU usage time. Seconds
      -v size: Sets the maximum value of virtual memory. Unit: kbytes
      Add something like ulimit -f 1000 to the end of /etc/profile so that each session will take effect when logged in.

      Ps:

      Permanent change

      remove
      Limits on maximum number of processes and maximum number of files open for Linux systems:

      Vi/etc/security/limits. Conf

      # Add the following line

      * Soft noproc 11000 # soft connection

      * Hard noproc 11000 # hard connection

      * soft nofiles 4100

      * hard nofiles 4100

      Note: * represents for all users, noproc represents the maximum number of processes, nofile represents the maximum number of open files

      Refer to the address: http://blog.csdn.net/jlds123/article/details/9146865