10. Frequently Encountered Error Messages
10.1. Modprobe Can't Locate Module, XXX, and Similar Messages.
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 <module-name> off |
And use the name of the module that appears in the error message.
[J.H.M. Dassen]
10.2. Unknown Terminal Type ``linux'' and Similar.
In early kernels the default console terminal type has changed from ``console'' to ``linux.'' You must edit /etc/termcap to change the line reading:
to
(there may be an additional ``dumb'' in there—if so it should be removed.)
To get the editor to work you may need type:
(for bash and ksh), or
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 |
10.4. ld: unrecognized option '-m486'
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.
10.5. GCC Says, ``Internal compiler error.''
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.'''')
10.6. Make Says, ``Error 139.''
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: (``The Machine Runs 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/.
10.9. Warning--bdflush Not Running.
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.
10.11. EXT2-fs: warning: mounting unchecked file system.
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 (``Where Are the Linux FTP Archives?'') 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.
10.12. EXT2-fs warning: maximal count reached.
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. (``Where Are the Linux FTP Archives?'')
The maximal number of mounts value can be examined and changed using the tune2fs program from this package.
10.14. df Says, ``Cannot read table of mounted file systems.''
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 /etc/rc.local or /etc/rc.d/*), using something like
Some old Linux distributions have an entry for the root partition in /etc/mtab made in /etc/rc* by using rdev. That is incorrect—the newer versions of mount do this automatically.
Some old distributions also have a line in /etc/fstab that looks like:
/dev/sdb1 /root ext2 defaults |
The entry for /root should read simply /.
10.16. fdisk: Partition 1 does not start on cylinder boundary.
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.
10.18. A Mtools Utility Says It Cannot Initialize Drive XYZ.
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? Note—you should
never use mtools to access files on an msdosfs
mounted partition or disk!
10.19. At the Start of Booting: Memory tight
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.'')
10.20. The System Log says, ``end_request: I/O error, ....''
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]
10.21. ``You don't exist. Go away.''
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).
10.22. ``Operation not permitted.''
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]
10.23. programname: error in loading shared libraries: lib xxx..so. x: cannot open shared object file: No such file or directory.
A message like this, when the program that you're trying to run uses
shared libraries, usually means one of two
things: the program was either compiled on
a machine that had a different set of libraries
or library paths than yours; or you've upgraded
your libraries but not the program.
Executable programs that are linked with dynamic libraries, expect the full pathname
of each of the library files it requires.
So do the shared libraries, if they rely on
other libraries. This is so the shared object
dependencies remain as unambiguous as possible,
and also as a security measure.
Short of recompiling the executable file for the libraries on the system—probably
the most desirable alternative in the long
run—you can try to determine which libraries
the executable file needs with the command:
``ldd programname.'' The output will be a list of the shared libraries on the system that the
program needs to run, as well as the missing
libraries. You can then add the library packages,
or if the libraries already exist in a different
directory, you can create a symbolic link
so the program can find it. For example, if
the program requires /usr/lib/libncurses.so.2,
and your machine has /lib/libncurses.so.2,
you can create a link where the program expects
to find the library; e.g.:
# cd /usr/lib && ln -s /lib/libncurses.so.2 . |
You should note, however, that creating library links like these should be considered
a security risk, and the additional links
you create will not be compatible with future
upgrades. It's simply a quick fix for backward
compatibility.
Also, it may take some guesswork to determine in exactly which of the system
library directories the program expects to
find a shared library file, because ldd will not list the paths of libraries it can't find. A program most likely will
tell the run-time linker, /lib/ld.so, to look for shared libraries in /lib, /usr/lib, /usr/local/lib, or /usr/X11R6/lib, if it's an X client. But that doesn't mean that libraries can't be installed
elsewhere. It helps to have some idea of the
original library configuration before proceeding.
Also be sure to run ldconfig after creating the symbolic link, so that ld.so has an updated view of the system's libraries. You should also make certain
that all of the library directories are listed
in /etc/ld.so.conf, and perhaps in the LD_LIBRARY_PATH environment variable.
10.24. ``init: Id "x" respawning too fast: disabled for 5 minutes.''
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]
10.25. FTP server says: ``421 service not available, remote server has closed
connection.''
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 distriubtions
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 theftpd/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.
