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Yang Xiaopeng writes:

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>I'm sure that no user process use old root now,  but when run "umount
>/old_root", it says:
>   umount: /old_root: Device or resource busy
>
>I have tried to remount /proc within the new root *after* chroot, but
>get the same result.
>
>
I found the problem, I said that no user process use old root when run
my scripts, but
I'm wrong, actually there is a '3' fd open the file
"/old_root/dev/console". By adding
debug message in init/init.c, I found the problem: when init restart(in
exec_signal()),
before open the new terminal device, there is still a file opened(I
don't know which file it is), so the
terminal device(stdin) get fd '1', and the first dup(0)(stdout) return
'2', the second(stderr) return '3'.

I attach a simple patch to solve this problem.
This commit is contained in:
Eric Andersen 2003-07-29 06:33:12 +00:00
parent 930c59675a
commit 9cdef5d928
1 changed files with 5 additions and 0 deletions
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5
init/init.c
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@ -735,6 +735,11 @@ static void exec_signal(int sig)
sigaddset(&unblock_signals, SIGTSTP); sigaddset(&unblock_signals, SIGTSTP);
sigprocmask(SIG_UNBLOCK, &unblock_signals, NULL); sigprocmask(SIG_UNBLOCK, &unblock_signals, NULL);
/* Close whatever files are open. */
close(0);
close(1);
close(2);
/* Open the new terminal device */ /* Open the new terminal device */
if ((device_open(a->terminal, O_RDWR)) < 0) { if ((device_open(a->terminal, O_RDWR)) < 0) {
if (stat(a->terminal, &sb) != 0) { if (stat(a->terminal, &sb) != 0) {