A shutdown is impossible in 2.4.18-27.

A shutdown is impossible in 2.4.18-27.

[Tomita, Haruo]

Hi All,

The problem whose shutdown is impossible in 2.4.18-27 has occurred.
2.4.18-27 is  Kernel upgrade of Red Hat 8.0.
The ttyS1 is used as the serial console in my environment.
If a shutdown is performed, it will stop at mgetty.
The stack trace extracted by sysrq is as follows.

mgetty        S 00000003     0 25524      1               20598 (L-TLB)
Call Trace: [<c0123c9d>] schedule_timeout [kernel] 0xad (0xc2415e28))
[<e0800ef5>] journal_get_write_access_R2b76932b [jbd] 0x55 (0xc2415e48))
[<c017b4de>] tty_wait_until_sent [kernel] 0x9e (0xc2415e60))
[<e08151f5>] ext3_reserve_inode_write [ext3] 0x75 (0xc2415e68))
[<c018d012>] rs_close [kernel] 0x152 (0xc2415e9c))
[<c01771ef>] release_dev [kernel] 0x57f (0xc2415ebc))
[<c012c9d0>] zap_pte_range [kernel] 0xf0 (0xc2415ee4))
[<c012ad8b>] do_zap_page_range [kernel] 0x8b (0xc2415f0c))
[<c017762f>] tty_release [kernel] 0xf (0xc2415f30))
[<c014121c>] fput [kernel] 0xfc (0xc2415f38))
[<c013f84d>] filp_close [kernel] 0x4d (0xc2415f54))
[<c011e8ec>] close_files [kernel] 0x7c (0xc2415f6c))
[<c011da78>] put_files_struct [kernel] 0x28 (0xc2415f8c))
[<c011e0e5>] do_exit [kernel] 0xc5 (0xc2415f9c))
[<c012ddda>] sys_munmap [kernel] 0x4a (0xc2415fa4))
[<c011e2a3>] sys_exit [kernel] 0x13 (0xc2415fb8))
[<c0109147>] system_call [kernel] 0x33 (0xc2415fc0))

When tty_wait_until_sent() is investigated,
I think that it does not escape from the following loops.

       do {
#ifdef TTY_DEBUG_WAIT_UNTIL_SENT
                printk(KERN_DEBUG "waiting %s...(%d)\n", tty_name(tty, buf),
                       tty->driver.chars_in_buffer(tty));
#endif
                set_current_state(TASK_INTERRUPTIBLE);
                if (signal_pending(current))
                        goto stop_waiting;
                if (!tty->driver.chars_in_buffer(tty))
                        break;
                timeout = schedule_timeout(timeout);
        } while (timeout);

I want to hear everybody's opinion. Please let me know your idea.

Regards,
Haruo