gvisor proc mount

https://github.com/google/gvisor/issues/1397

 

#include <sys/socket.h>
#include <sys/un.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#define MY_SOCK_PATH "/tmp/hello"
#define LISTEN_BACKLOG 50

#define handle_error(msg) \
    do { perror(msg); /*exit(EXIT_FAILURE);*/ } while (0)

int
main(int argc, char *argv[])
{
    unsigned char buff[32];
    int sfd, cfd, idx;
    struct sockaddr_un my_addr, peer_addr;
    socklen_t peer_addr_size;

    for (idx=0;idx<60000;idx++) {
        sfd = socket(AF_UNIX, SOCK_STREAM, 0);
        if (sfd == -1)
            handle_error("socket");

        memset(buff,0,32);
        sprintf(buff,"%s%d",MY_SOCK_PATH,idx);
        memset(&my_addr, 0, sizeof(struct sockaddr_un));
                            /* Clear structure */
        my_addr.sun_family = AF_UNIX;
        strncpy(my_addr.sun_path, buff,
                sizeof(my_addr.sun_path) - 1);

        if (bind(sfd, (struct sockaddr *) &my_addr,
                sizeof(struct sockaddr_un)) == -1)
            handle_error("bind");

        close(sfd);
        unlink(buff);
    }
}

 

$cat /home/script/taskmnts.sh
 #!/bin/sh

 while true
 do
     cat /proc/self/mounts  > /dev/null
 done

 

 

root@cloud:~# docker run -it --runtime=runsc-kvm  --rm  debian /bin/bash
root@f2b9fb2551cd:/# ls
bin  boot  dev  etc  gov  home  lib  media  mnt  opt  proc  root  run  sbin  srv  sys  tmp  usr  var
root@f2b9fb2551cd:/# ./gov
root@f2b9fb2551cd:/# ./gov
root@f2b9fb2551cd:/# while true
>  do
>  cat /proc/self/mounts  > /dev/null
>  done

 

root@cloud:~# dlv attach 942458
Type 'help' for list of commands.
(dlv) b pkg/sentry/fs/mounts.go:418
Breakpoint 1 set at 0x32e8f0 for gvisor.dev/gvisor/pkg/sentry/fs.(*MountNamespace).findMountLocked() pkg/sentry/fs/mounts.go:418
(dlv) c
> gvisor.dev/gvisor/pkg/sentry/fs.(*MountNamespace).findMountLocked() pkg/sentry/fs/mounts.go:418 (hits goroutine(278):1 total:1) (PC: 0x32e8f0)
Warning: debugging optimized function
(dlv) bt
 0  0x000000000032e8f0 in gvisor.dev/gvisor/pkg/sentry/fs.(*MountNamespace).findMountLocked
    at pkg/sentry/fs/mounts.go:418
 1  0x000000000032e874 in gvisor.dev/gvisor/pkg/sentry/fs.(*MountNamespace).FindMount
    at pkg/sentry/fs/mounts.go:415
 2  0x00000000007c326c in gvisor.dev/gvisor/pkg/sentry/fs/proc.forEachMount
    at pkg/sentry/fs/proc/mounts.go:52
 3  0x00000000007c38dc in gvisor.dev/gvisor/pkg/sentry/fs/proc.(*mountsFile).ReadSeqFileData
    at pkg/sentry/fs/proc/mounts.go:204
 4  0x00000000003c792c in gvisor.dev/gvisor/pkg/sentry/fs/proc/seqfile.(*SeqFile).updateSourceLocked
    at pkg/sentry/fs/proc/seqfile/seqfile.go:180
 5  0x00000000003c82f4 in gvisor.dev/gvisor/pkg/sentry/fs/proc/seqfile.(*seqFileOperations).Read
    at pkg/sentry/fs/proc/seqfile/seqfile.go:229
 6  0x000000000031f234 in gvisor.dev/gvisor/pkg/sentry/fs.(*File).Readv
    at pkg/sentry/fs/file.go:245
 7  0x00000000005813a8 in gvisor.dev/gvisor/pkg/sentry/syscalls/linux.readv
    at pkg/sentry/syscalls/linux/sys_read.go:292
 8  0x000000000057fae0 in gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Read
    at pkg/sentry/syscalls/linux/sys_read.go:72
 9  0x0000000000522ea4 in gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall
    at pkg/sentry/kernel/task_syscall.go:104
10  0x0000000000523c5c in gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke
    at pkg/sentry/kernel/task_syscall.go:239
11  0x00000000005238dc in gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter
    at pkg/sentry/kernel/task_syscall.go:199
12  0x00000000005233e0 in gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall
    at pkg/sentry/kernel/task_syscall.go:174
13  0x0000000000518e00 in gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute
    at pkg/sentry/kernel/task_run.go:282
14  0x0000000000517d9c in gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run
    at pkg/sentry/kernel/task_run.go:97
15  0x0000000000077c84 in runtime.goexit
    at src/runtime/asm_arm64.s:1136
(dlv) clearall
Breakpoint 1 cleared at 0x32e8f0 for gvisor.dev/gvisor/pkg/sentry/fs.(*MountNamespace).findMountLocked() pkg/sentry/fs/mounts.go:418
(dlv) quit
Would you like to kill the process? [Y/n] n
root@cloud:~#