From 9cdef5d9286839a0b787c25f41633508f8623765 Mon Sep 17 00:00:00 2001 From: Eric Andersen Date: Tue, 29 Jul 2003 06:33:12 +0000 Subject: Yang Xiaopeng writes: >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. --- init/init.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'init') diff --git a/init/init.c b/init/init.c index 7e24eacdd..1ecc43e16 100644 --- a/init/init.c +++ b/init/init.c @@ -735,6 +735,11 @@ static void exec_signal(int sig) sigaddset(&unblock_signals, SIGTSTP); sigprocmask(SIG_UNBLOCK, &unblock_signals, NULL); + /* Close whatever files are open. */ + close(0); + close(1); + close(2); + /* Open the new terminal device */ if ((device_open(a->terminal, O_RDWR)) < 0) { if (stat(a->terminal, &sb) != 0) { -- cgit v1.2.3