Ok, one more thing to try. Still in serial_core.c, let's also add a BUG_ON(info->tty==NULL) in the middle of uart_write_wakeup(). I don't expect this bug to trigger. My current guess is that the tty is closed between scheduling and running the tasklet. How about adding a printk after each time where info->tty is set: near line 1224 in uart_close(), line 1320 in uart_hangup(), and line 1538 in uart_open(). If my guess is right, we will see a uart_close just before the BUG from the tasklet.
Sounds quite possible, this reminds me that when the machine starts up, minicom changes serial stgatus from "Offline" to "Online" and it remains Online during bootup but is Offiline during normal work. It seems to work though - when I do shutdown, I see all the messages scrolling by.
With these printk's and the additional BUG check, the new BUG trigges very early on boot, during init startup:
VFS: Mounted root (ext3 filesystem) readonly.
Freeing unused kernel memory: 104k freed
uart_open setting info->tty = f0846000
uart_open setting info->tty = f0846000
uart_close setting info->tty = NULL
uart_open setting info->tty = f0846000
uart_close setting info->tty = NULL
kernel BUG at drivers/serial/serial_core.c:73!
\|/ ____ \|/
"@'/ ,. \`@"
/_| \__/ |_\
\__U_/
init(1): Kernel bad trap [#1]
PSR: 40400fc4 PC: f00f49a8 NPC: f00f49ac Y: 00000000 Not tainted
PC: <uart_write_wakeup+0x54/0x60>
%G: 00000049 f0195c00 f0195fc4 40400fe2 f002f084 f0195c00 f0862000 00000000
%O: 00000032 f017eaa8 00000049 500a4880 500197c8 00000314 f0863db0 f00f49a0
RPC: <uart_write_wakeup+0x4c/0x60>
%L: 40800fc5 f0011530 f0011534 00000020 0000000c 6d610000 f0862000 50171e9c
%I: f01d1f20 00049000 00000004 80808080 00000001 00000050 f0863e18 f00f900c
Caller[f00f900c]: sunzilog_transmit_chars+0xf8/0x180
Caller[f00f91c8]: sunzilog_interrupt+0x134/0x174
Caller[f0012f58]: handler_irq+0x78/0xa4
Caller[f0010758]: patch_handler_irq+0x0/0x24
Caller[500097e0]: 0x500097e0
Instruction DUMP: 92102049 7ffc7846 901222a8 <91d02005> 81c7e008 81e80000 9
Kernel panic - not syncing: Aiee, killing interrupt handler!-- Meelis Roos ([EMAIL PROTECTED]) - To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
