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-rw-r--r--Documentation/uml/UserModeLinux-HOWTO.txt66
1 files changed, 8 insertions, 58 deletions
diff --git a/Documentation/uml/UserModeLinux-HOWTO.txt b/Documentation/uml/UserModeLinux-HOWTO.txt
index 544430e39980..b60590eca18f 100644
--- a/Documentation/uml/UserModeLinux-HOWTO.txt
+++ b/Documentation/uml/UserModeLinux-HOWTO.txt
@@ -157,7 +157,7 @@
157 13. What to do when UML doesn't work 157 13. What to do when UML doesn't work
158 158
159 13.1 Strange compilation errors when you build from source 159 13.1 Strange compilation errors when you build from source
160 13.2 UML hangs on boot after mounting devfs 160 13.2 (obsolete)
161 13.3 A variety of panics and hangs with /tmp on a reiserfs filesystem 161 13.3 A variety of panics and hangs with /tmp on a reiserfs filesystem
162 13.4 The compile fails with errors about conflicting types for 'open', 'dup', and 'waitpid' 162 13.4 The compile fails with errors about conflicting types for 'open', 'dup', and 'waitpid'
163 13.5 UML doesn't work when /tmp is an NFS filesystem 163 13.5 UML doesn't work when /tmp is an NFS filesystem
@@ -379,31 +379,6 @@
379 bug fixes and enhancements that have gone into subsequent releases. 379 bug fixes and enhancements that have gone into subsequent releases.
380 380
381 381
382 If you build your own kernel, and want to boot it from one of the
383 filesystems distributed from this site, then, in nearly all cases,
384 devfs must be compiled into the kernel and mounted at boot time. The
385 exception is the SuSE filesystem. For this, devfs must either not be
386 in the kernel at all, or "devfs=nomount" must be on the kernel command
387 line. Any disagreement between the kernel and the filesystem being
388 booted about whether devfs is being used will result in the boot
389 getting no further than single-user mode.
390
391
392 If you don't want to use devfs, you can remove the need for it from a
393 filesystem by copying /dev from someplace, making a bunch of /dev/ubd
394 devices:
395
396
397 UML# for i in 0 1 2 3 4 5 6 7; do mknod ubd$i b 98 $i; done
398
399
400
401
402 and changing /etc/fstab and /etc/inittab to refer to the non-devfs
403 devices.
404
405
406
407 22..22.. CCoommppiilliinngg aanndd iinnssttaalllliinngg kkeerrnneell mmoodduulleess 382 22..22.. CCoommppiilliinngg aanndd iinnssttaalllliinngg kkeerrnneell mmoodduulleess
408 383
409 UML modules are built in the same way as the native kernel (with the 384 UML modules are built in the same way as the native kernel (with the
@@ -839,9 +814,7 @@
839 +o None - device=none 814 +o None - device=none
840 815
841 816
842 This causes the device to disappear. If you are using devfs, the 817 This causes the device to disappear.
843 device will not appear in /dev. If not, then attempts to open it
844 will return -ENODEV.
845 818
846 819
847 820
@@ -1047,7 +1020,7 @@
1047 1020
1048 Note that the IP address you assign to the host end of the tap device 1021 Note that the IP address you assign to the host end of the tap device
1049 must be different than the IP you assign to the eth device inside UML. 1022 must be different than the IP you assign to the eth device inside UML.
1050 If you are short on IPs and don't want to comsume two per UML, then 1023 If you are short on IPs and don't want to consume two per UML, then
1051 you can reuse the host's eth IP address for the host ends of the tap 1024 you can reuse the host's eth IP address for the host ends of the tap
1052 devices. Internally, the UMLs must still get unique IPs for their eth 1025 devices. Internally, the UMLs must still get unique IPs for their eth
1053 devices. You can also give the UMLs non-routable IPs (192.168.x.x or 1026 devices. You can also give the UMLs non-routable IPs (192.168.x.x or
@@ -2058,7 +2031,7 @@
2058 there are multiple COWs associated with a backing file, a -d merge of 2031 there are multiple COWs associated with a backing file, a -d merge of
2059 one of them will invalidate all of the others. However, it is 2032 one of them will invalidate all of the others. However, it is
2060 convenient if you're short of disk space, and it should also be 2033 convenient if you're short of disk space, and it should also be
2061 noticably faster than a non-destructive merge. 2034 noticeably faster than a non-destructive merge.
2062 2035
2063 2036
2064 2037
@@ -3898,29 +3871,6 @@
3898 3871
3899 3872
3900 3873
3901 1133..22.. UUMMLL hhaannggss oonn bboooott aafftteerr mmoouunnttiinngg ddeevvffss
3902
3903 The boot looks like this:
3904
3905
3906 VFS: Mounted root (ext2 filesystem) readonly.
3907 Mounted devfs on /dev
3908
3909
3910
3911
3912 You're probably running a recent distribution on an old machine. I
3913 saw this with the RH7.1 filesystem running on a Pentium. The shared
3914 library loader, ld.so, was executing an instruction (cmove) which the
3915 Pentium didn't support. That instruction was apparently added later.
3916 If you run UML under the debugger, you'll see the hang caused by one
3917 instruction causing an infinite SIGILL stream.
3918
3919
3920 The fix is to boot UML on an older filesystem.
3921
3922
3923
3924 1133..33.. AA vvaarriieettyy ooff ppaanniiccss aanndd hhaannggss wwiitthh //ttmmpp oonn aa rreeiisseerrffss ffiilleessyyss-- 3874 1133..33.. AA vvaarriieettyy ooff ppaanniiccss aanndd hhaannggss wwiitthh //ttmmpp oonn aa rreeiisseerrffss ffiilleessyyss--
3925 tteemm 3875 tteemm
3926 3876
@@ -3953,9 +3903,9 @@
3953 3903
3954 1133..55.. UUMMLL ddooeessnn''tt wwoorrkk wwhheenn //ttmmpp iiss aann NNFFSS ffiilleessyysstteemm 3904 1133..55.. UUMMLL ddooeessnn''tt wwoorrkk wwhheenn //ttmmpp iiss aann NNFFSS ffiilleessyysstteemm
3955 3905
3956 This seems to be a similar situation with the resierfs problem above. 3906 This seems to be a similar situation with the ReiserFS problem above.
3957 Some versions of NFS seems not to handle mmap correctly, which UML 3907 Some versions of NFS seems not to handle mmap correctly, which UML
3958 depends on. The workaround is have /tmp be non-NFS directory. 3908 depends on. The workaround is have /tmp be a non-NFS directory.
3959 3909
3960 3910
3961 1133..66.. UUMMLL hhaannggss oonn bboooott wwhheenn ccoommppiilleedd wwiitthh ggpprrooff ssuuppppoorrtt 3911 1133..66.. UUMMLL hhaannggss oonn bboooott wwhheenn ccoommppiilleedd wwiitthh ggpprrooff ssuuppppoorrtt
@@ -4022,7 +3972,7 @@
4022 nneett 3972 nneett
4023 3973
4024 If you can connect to the host, and the host can connect to UML, but 3974 If you can connect to the host, and the host can connect to UML, but
4025 you can not connect to any other machines, then you may need to enable 3975 you cannot connect to any other machines, then you may need to enable
4026 IP Masquerading on the host. Usually this is only experienced when 3976 IP Masquerading on the host. Usually this is only experienced when
4027 using private IP addresses (192.168.x.x or 10.x.x.x) for host/UML 3977 using private IP addresses (192.168.x.x or 10.x.x.x) for host/UML
4028 networking, rather than the public address space that your host is 3978 networking, rather than the public address space that your host is
@@ -4671,7 +4621,7 @@
4671 Chris Reahard built a specialized root filesystem for running a DNS 4621 Chris Reahard built a specialized root filesystem for running a DNS
4672 server jailed inside UML. It's available from the download 4622 server jailed inside UML. It's available from the download
4673 <http://user-mode-linux.sourceforge.net/dl-sf.html> page in the Jail 4623 <http://user-mode-linux.sourceforge.net/dl-sf.html> page in the Jail
4674 Filesysems section. 4624 Filesystems section.
4675 4625
4676 4626
4677 4627