9. Frequently Encountered Error Messages

A: These types of messages mostly occur at boot time or shutdown. If modprobe, insmod, or rmmod complain about not being able to find a module, add the following to the [/etc/modules.conf] or [/etc/modutils/aliases] file, whichever is present on your system.

$ alias off

And use the name of the module that appears in the error message.

[J.H.M. Dassen]

A: In early kernels the default console terminal type has changed from ``console'' to ``linux.'' You must edit [/etc/termcap] to change the line reading:

console|con80x25:

to

linux|console|con80x25:

(there may be an additional ``dumb'' in there - if so it should be removed.)

To get the editor to work you may need type:

$ TERM=console

(for bash and ksh), or

$ setenv TERM console

for csh or tcsh.

Some programs use [/usr/lib/terminfo] instead of [/etc/termcap]. For these programs you should upgrade your terminfo package, which is part of ncurses.

The same is true for X terminal displays. If your distribution sets the TERM to something strange like xterm-24-color, you can simply reset it to a generic value from the command line:

$ TERM="xterm"; export TERM

A: You are trying to use the old network configuration utilities. The new ones can be found on ftp.linux.org.uk/pub/linux/Networking/PROGRAMS/NetTools/ (source only, I'm afraid).

Note that they cannot be used just like the old-style programs. See the NET-2 HOWTO for instructions on how to set up the old-style networking programs correctly. Even better, see the NET-3 HOWTO and upgrade your networking software.

A: You have an old version of ld. Install a newer binutils package that contains an updated ld. Look on tsx-11.mit.edu in [/pub/linux/packages/GCC/] for [binutils-2.6.0.2.bin.tar.gz].

A: If the fault is repeatable (i.e., it always happens at the same place in the same file - even after rebooting and trying again, using a stable kernel) you have discovered a bug in GCC. See the GCC Info documentation (type F1-i in Emacs, and select GCC from the menu) for details on how to report the error. Make sure you have the latest version, though.

Note that this is probably not a Linux-specific problem. Unless you are compiling a program many other Linux users also compile, you should not post your bug report to any of the comp.os.linux groups.

If the problem is not repeatable, you may be experiencing memory corruption. Refer to the answer: (``Make Says, ``Error 139.'''')

A: Your compiler (GCC) dumped core. You probably have a corrupted, buggy, or old version of GCC - get the latest release or EGCS. Alternatively, you may be running out of swap space. Refer to: (``Why Does the Machine Run Very Slowly with GCC / X / ...?'')

If this doesn't fix the problem, you are probably having problems with memory or disk corruption. Check that the clock rate, wait states, and refresh timing for your SIMMS and cache are correct (hardware manuals are sometimes wrong, too). If so, you may have some marginal SIMMS, or a faulty motherboard or hard disk or controller.

Linux is a very good memory tester - much better than MS-DOS based memory test programs.

Reportedly, some clone x87 math coprocessors can cause problems. Try compiling a kernel with math emulation (``How To Upgrade/Recompile a Kernel'') no387 kernel command line flag on the LILO prompt to force the kernel to use math emulation, or it may be able to work and still use the '387, with the math emulation compiled in but mainly unused.

More information about this problem is available on the Web at http://www.bitwizard.nl/sig11/.

A: Your root directory and all the directories up to your home directory must be readable and executable by everybody. See the manual page for chmod or a book on Unix for how to fix the problem.

A: Your [/var/run/utmp] is screwed up. You should have

/var/run/utmp

A: Modern kernels use a better strategy for writing cached disk blocks. In addition to the kernel changes, this involves replacing the old update program which used to write everything every 30 seconds with a more subtle daemon (actually a pair), known as bdflush. Get [bdflush-]n.n[.tar.gz] from the same place as the kernel source code (``How To Upgrade/Recompile a Kernel'') and compile and install it. bdflush should be started before the usual boot-time file system checks. It will work fine with older kernels as well, so there's no need to keep the old update around.

A: This is nothing to worry about. The message means that your version route is a little out of date, compared to the kernel. You can make the message go away by getting a new version of route from the same place as the kernel source code. (``How To Upgrade/Recompile a Kernel'')

A: You need to run e2fsck (or fsck -t ext2 if you have the fsck front end program) with the -a option to get it to clear the ``dirty'' flag, and then cleanly unmount the partition during each shutdown.

The easiest way to do this is to get the latest fsck, umount, and shutdown commands, available in Rik Faith's [util-linux] package (``'') You have to make sure that your [/etc/rc*/] scripts use them correctly.

NB: Don't try to check a file system that's mounted read/write. This includes the root partition if you don't see

VFS: mounted root ... read-only

at boot time. You must arrange to mount the root file system read/only to start with, check it if necessary, and then remount it read/write. Almost all distributions do this. If your's doesn't, read the documentation that comes with [util-linux] to find out how to do this.

Note that you need to specify the -n option to mount so it won't try to update [/etc/mtab], since the root file system is still read-only, and this will otherwise cause it to fail.

A: This message is issued by the kernel when it mounts a file system that's marked as clean, but whose "number of mounts since check" counter has reached the predefined value. The solution is to get the latest version of the ext2fs utilities ([e2fsprogs-0.5b.tar.gz] at the time of writing) from the usual sites. (``'')

The maximal number of mounts value can be examined and changed using the tune2fs program from this package.

A: Kernels from 1.0 onwards support checking a file system based on the elapsed time since the last check as well as by the number of mounts. Get the latest version of the ext2fs utilities. (``EXT2-fs warning: maximal count reached'')

A: There is probably something wrong with your [/etc/mtab] or [/etc/fstab] files. If you have a reasonably new version of mount, [/etc/mtab] should be emptied or deleted at boot time (in

 $ rm -f /etc/mtab*

A: A If the partition number (X, above) is 1, this is the same problem as in fdisk: Partition 1 does not start on cylinder boundary.

If the partition begins or ends on a cylinder numbered greater than 1024, this is because the standard DOS disk geometry information format in the partition table can't cope with cylinder numbers with more than 10 bits. You should see (``How Can I Get Linux to Work With My Disk?'')

A: The version of fdisk that comes with many Linux systems creates partitions that fail its own validity checking. Unfortunately, if you've already installed your system, there's not much you can do about this, apart from copying the data off the partition, deleting and remaking it, and copying the data back.

You can avoid the problem by getting the latest version of fdisk, from Rik Faith's util-linux package (available on all the usual FTP sites). Alternatively, if you are creating a new partition 1 that starts in the first cylinder, you can do the following to get a partition that fdisk likes.

• Create partition 1 in the normal way. A `p' listing will produce the mismatch complaint.

• Type u to set sector mode and do p again. Copy down the number from the End column.

• Delete partition 1.

• While still in sector mode, re-create partition 1. Set the first sector to match the number of sectors per track. This is the sector number in the first line of the p output. Set the last sector to the value you wrote down in the step above.

• Type u to reset cylinder mode and continue with other partitions.

  Ignore the message about unallocated sectors. They refer to the sectors on the first track apart from the Master Boot Record, and they are not used if you start the first partition in track 2.

A: The PC disk partitioning scheme works in 512-byte sectors, but Linux uses 1K blocks. If you have a partition with an odd number of sectors, the last sector is wasted. Ignore the message.

A: This means that mtools is having trouble accessing the drive. This can be due to several things.

Often this is due to the permissions on floppy drive devices ([/dev/fd0*] and [/dev/fd1*]) being incorrect. The user running mtools must have the appropriate access. See the manual page for chmod for details.

Most versions of mtools distributed with Linux systems (not the standard GNU version) use the contents of a file [/etc/mtools] to determine which devices and densities to use, in place of having this information compiled into the binary. Mistakes in this file often cause problems. There is often no documentation about this.

For the easiest way to access your MS-DOS files (especially those on a hard disk partition) see How do I access files on my DOS partition or floppy? Noteyou should never use mtools to access files on an msdosfs mounted partition or disk!

A: This means that you have an extra-large kernel, which means that Linux has to do some special memory-management magic to be able to boot itself from the BIOS. It isn't related to the amount of physical memory in your machine. Ignore the message, or compile a kernel containing only the drivers and features you need. (``How To Upgrade/Recompile a Kernel'')

A: This error message, and messages like it, almost always indicate a hardware error with a hard drive.

This commonly indicates a hard drive defect. The only way to avoid further data loss is to completely shut own the system. You must also make sure that whatever data is on the drive is backed up, and restore it to a non-defective hard drive.

This error message may also indicate a bad connection to the drive, especially with home brew systems. If you install an IDE drive, always use new ribbon cables. It's probably is a good idea with SCSI drives, too.

In one instance, this error also seemed to coincide with a bad ground between the system board and the chassis. Be sure that all electrical connections are clean and tight before placing the blame on the hard drive itself.

[Peter Moulder, Theodore Ts'o]

A: This is not a viral infection. It comes from programs like write, talk, and wall, if your invoking UID doesn't correspond to a valid user (probably due to [/etc/passwd] being corrupted), or if the session (pseudoterminal, specifically) you're using isn't properly registered in the [utmp] file (probably because you invoked it in a funny way).

A: One or more of the file's or directory's attribute bits are set incorrectly. If the ``I'' bit is set, for example, you won't be able to change file permissions with chmod.

The solution is to use lsattr to display file and directory attributes, and chattr to set and unset them. The programs' documentation is contained in their manual pages.

[Paul Campbell]

A: x: cannot open shared object file: No such file or directory.

A: In most distributions this means that the system is booting by default into runlevel 5, which is supposed to respawn (re-start again after it's been exited) a graphical login via xdm, kdm, gdm, or whatever, and the system can't locate the program.

However, ``Id'' can also indicate the absence or misconfiguration of another program, like mingetty, if init tries to respawn itself more than 10 times in 2 minutes.

Id ``x'' is the number in the leftmost column of the [/etc/inittab] file:

# Run gettys in standard runlevels 1:2345:respawn:/sbin/mingetty tty1 2:2345:respawn:/sbin/mingetty tty2 3:2345:respawn:/sbin/mingetty tty3 4:2345:respawn:/sbin/mingetty tty4 5:2345:respawn:/sbin/mingetty tty5 6:2345:respawn:/sbin/mingetty tty6

Commenting the offending line out and then fixing the errant program and testing on the command line will allow you to see any error messages that go to standard error output (console) if the errors are not going to the system log file. Uncomment the line and restart init with ``kill -SIGHUP 1'' or ``telinit q'' to cause init to reinitialize and reread the [/etc/inittab] file.

Some systems, however, rewrite [/etc/inittab] when booting. In that case, refer to the init man page, and/or the settings in [/etc/sysconfig/init].

Refer to the init and [/etc/inittab] man pages for detailed information.

[Carl King]

A: If an FTP server won't allow logins, it is probably configured correctly, but the problem is probably with authorizing users at login. FTP servers in current distributions often authorize users with the Pluggable Authentication Modules library, in which case there should be an authorization file [/etc/pam.d/ftp]. A generic authorization file looks like this. (The line break on the first ``auth'' line is for readability. The entry is actually a single, long line).

#%PAM-1.0 auth required /lib/security/pam_listfile.so item=user sense=deny file=/etc/ftpusers onerr=succeed auth required /lib/security/pam_pwdb.so shadow nullok auth required /lib/security/pam_shells.so account required /lib/security/pam_pwdb.so session required /lib/security/pam_pwdb.so

Also, make sure the [/etc/ftpusers] file, or whatever users file is named in the first ``auth'' line, is configured correctly.

Btw, the sample [ftp] file above is actually the [ftpd/ftp.pam.sample] file from the [ftpd-BSD-0.3.1.tar.gz] package. Many thanks to David A. Madore for this much needed port.