boot hang at mounting proc filesystem, was Re: [uml-devel] null stdin/stdout strangeness - but getting there!

[William S. <wst...@po...>]

Good afternoon, Jeff,

On Wed, 8 Nov 2000, Jeff Dike wrote:

> If you really can't get the console to respond, gdb the tracing thread and
> 'printf "%s", log_buf'.  This will dump the contents of the kernel log.  Maybe
> there's something strange there.
>
> Also put 'debug' on the kernel command line, and when it hangs, ^C the gdb and
> 'bt' to see what it thinks is up.

	I compiled my own test10 and left in the symbols.  Added "debug"
to the command line and left off "</dev/null" for the moment.  It's now
hanging at mounting proc filesystem.  When that happens, I hit ctrl-c and
do a backtrace:

600000e
att 1
b start_kernel
c
GNU gdb 5.0
[snip]
This GDB was configured as "i386-redhat-linux"...
(gdb) att 1
Attaching to program: /home/wstearns/uml/rh6.2/linux, Pid 1
0x100b4701 in __kill ()
(gdb) b start_kernel
Breakpoint 1 at 0x100fcc5f: file init/main.c, line 514.
(gdb) c
Continuing.

Breakpoint 1, start_kernel () at init/main.c:514
514             printk(linux_banner);
(gdb) c
Continuing.

Program received signal SIGINT, Interrupt.
0x100ae7bd in set_user_thread (t=0x0, on=0, restore_state=0)
    at process_kern.c:72
72      {
(gdb) bt
#0  0x100ae7bd in set_user_thread (t=0x0, on=0, restore_state=0)
    at process_kern.c:72
#1  0x100ad779 in segv_handler (sig=11) at trap_user.c:263
#2  <signal handler called>
#3  0x10025722 in copy_mount_options (data=0x8058378, where=0x52d3fc80)
    at
/usr/src/uml-linux/linux-2.4.0-test10.uml/include/asm/arch/string.h:202
#4  0x10025a70 in sys_mount (dev_name=0x8058358 "/proc",
    dir_name=0x8058368 "/proc", type=0x8058378 "proc", flags=3236757504,
    data=0x0) at super.c:1430
#5  0x100ab7e2 in execute_syscall (syscall=21, args=0x52d3fce4)
    at syscall_kern.c:340
#6  0x100abc19 in syscall_handler (unused=0) at syscall_user.c:113
#7  <signal handler called>
#8  0x100b4701 in __kill ()
(gdb) printf "%s", log_buf
<4>tracing thread pid = 2617
<4>Linux version 2.4.0-test10-1um (ro...@sp...) (gcc version
2.96
20000731 (Red Hat Linux 7.0)) #1 Sat Nov 11 13:39:17 EST 2000
<4>On node 0 totalpages: 12288
<4>zone(0): 0 pages.
<4>zone(1): 12288 pages.
<4>zone(2): 0 pages.
<4>Kernel command line: mem=48M debug root=/dev/ubd0
<4>Calibrating delay loop... 710.41 BogoMIPS
<4>Memory: 48324k available
<4>Dentry-cache hash table entries: 8192 (order: 4, 65536 bytes)
<4>Buffer-cache hash table entries: 1024 (order: 0, 4096 bytes)
<4>Page-cache hash table entries: 16384 (order: 4, 65536 bytes)
<4>Inode-cache hash table entries: 4096 (order: 3, 32768 bytes)
<5>VFS: Diskquotas version dquot_6.4.0 initialized
<4>POSIX conformance testing by UNIFIX
<6>Linux NET4.0 for Linux 2.4
<6>Based upon Swansea University Computer Society NET3.039
<4>Starting kswapd v1.8
<4>pty: 256 Unix98 ptys configured
<4>RAMDISK driver initialized: 16 RAM disks of 4096K size 1024 blocksize
<6>loop: enabling 8 loop devices
<4>User-mode Linux network interface 0.005 (eth0)
---Type <return> to continue, or q <return> to quit---
<4>User-mode Linux network interface 0.005 (eth1)
<4>User-mode Linux network interface 0.005 (eth2)
<4>User-mode Linux network interface 0.005 (eth3)
<6>NET4: Linux TCP/IP 1.0 for NET4.0
<6>IP Protocols: ICMP, UDP, TCP
<4>IP: routing cache hash table of 512 buckets, 4Kbytes
<4>TCP: Hash tables configured (established 4096 bind 4096)
<4>ip_conntrack (384 buckets, 3072 max)
<4>ip_tables: (c)2000 Netfilter core team
<6>NET4: Unix domain sockets 1.0/SMP for Linux NET4.0.
<4>Initializing stdio console driver
<6>Initializing software serial port version 0
<4>serial line 0 assigned pty /dev/ptyp3
<4>ssl receive thread is pid 2627
<4>devfs: v0.102 (20000622) Richard Gooch (rg...@at...)
<4>devfs: devfs_debug: 0x0
<4>devfs: boot_options: 0x0
<4>VFS: Mounted root (ext2 filesystem) readonly.
<4>Mounted devfs on /dev
(gdb)

	For reference, the console shows the following lines after the
above devfs:

INIT: version 2.78 booting
Started device management daemon for /dev
                        Welcome to Red Hat Linux
                Press 'I' to enter interactive startup.
Mounting proc filesystem

	This appears to be a different problem than the "Hey, what
happened to fd0?" as I'm not using "</dev/null".
	Cheers,
	- Bill

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William Stearns (wst...@po...).  Mason, Buildkernel, named2hosts,
and ipfwadm2ipchains are at:                http://www.pobox.com/~wstearns
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