[uml-user] No devpts mount in chroot causes hang

[Adrian P. <a.p...@dn...>]

Using UML: 2.4.18-15 and a variant of Nick Craig-Woods perl script
(Thanks !) for running UML in chroot :-

pcedb85:~# mount 
/dev/sda1 on / type ext2 (rw,errors=remount-ro)
proc on /proc type proc (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
/dev/rootvg/usrlv on /usr type reiserfs (rw)
/dev/rootvg/varlv on /var type reiserfs (rw)
/dev/rootvg/tmplv on /tmp type reiserfs (rw)
/dev/rootvg/homelv on /home type reiserfs (rw)
/dev/rootvg/umllv on /uml type reiserfs (rw)
tmpfs on /uml/vb/tmp type tmpfs (rw,size=128M,mode=0750,gid=11100)

pcedb85:~# run_uml vb
About to run '/bin/linux root=/dev/ubd0 con=pts con0=fd:0,fd:1 ubd0=/dev/rootvg/vblv uml_dir=/tmp eth0=tuntap,tap0 mem=128M devfs=nomount umid=vb'
tracing thread pid = 4171
Linux version 2.4.18-15um (cfengine@dawn) (gcc version 2.95.4 20011006 (Debian prerelease)) #1 Tue Apr 9 08:55:32 GMT 2002
On node 0 totalpages: 32768
zone(0): 0 pages.
zone(1): 32768 pages.
zone(2): 0 pages.
Kernel command line: root=/dev/ubd0 con=pts con0=fd:0,fd:1 ubd0=/dev/rootvg/vblv uml_dir=/tmp eth0=tuntap,tap0 mem=128M devfs=nomount umid=vb
Calibrating delay loop... 674.84 BogoMIPS
Memory: 129008k available
Dentry-cache hash table entries: 16384 (order: 5, 131072 bytes)
Inode-cache hash table entries: 8192 (order: 4, 65536 bytes)
Mount-cache hash table entries: 2048 (order: 2, 16384 bytes)
Buffer-cache hash table entries: 8192 (order: 3, 32768 bytes)
Page-cache hash table entries: 32768 (order: 5, 131072 bytes)
Checking for host processor cmov support...Couldn't open /proc/cpuinfo, errno = 2
Checking for host processor xmm support...Couldn't open /proc/cpuinfo, errno = 2
Checking that ptrace can change system call numbers...OK
Checking that host ptys support output SIGIO...

This hangs (at least for several minutes after which I killed the
UML).

pcedb85:~# mount devpts /uml/vb/dev/pts -t devpts

makes sure that UML doesn't hang (although I haven't got a login
prompt yet, still working on that) :-

pcedb85:~# run_uml vb
About to run '/bin/linux root=/dev/ubd0 con=pts con0=fd:0,fd:1 ubd0=/dev/rootvg/vblv uml_dir=/tmp eth0=tuntap,tap0 mem=128M devfs=nomount umid=vb'
tracing thread pid = 4181
Linux version 2.4.18-15um (cfengine@dawn) (gcc version 2.95.4 20011006 (Debian prerelease)) #1 Tue Apr 9 08:55:32 GMT 2002
On node 0 totalpages: 32768
zone(0): 0 pages.
zone(1): 32768 pages.
zone(2): 0 pages.
Kernel command line: root=/dev/ubd0 con=pts con0=fd:0,fd:1 ubd0=/dev/rootvg/vblv uml_dir=/tmp eth0=tuntap,tap0 mem=128M devfs=nomount umid=vb
Calibrating delay loop... 674.84 BogoMIPS
Memory: 129008k available
Dentry-cache hash table entries: 16384 (order: 5, 131072 bytes)
Inode-cache hash table entries: 8192 (order: 4, 65536 bytes)
Mount-cache hash table entries: 2048 (order: 2, 16384 bytes)
Buffer-cache hash table entries: 8192 (order: 3, 32768 bytes)
Page-cache hash table entries: 32768 (order: 5, 131072 bytes)
Checking for host processor cmov support...Couldn't open /proc/cpuinfo, errno = 2
Checking for host processor xmm support...Couldn't open /proc/cpuinfo, errno = 2
Checking that ptrace can change system call numbers...OK
Checking that host ptys support output SIGIO...No, enabling workaround
POSIX conformance testing by UNIFIX
Linux NET4.0 for Linux 2.4
Based upon Swansea University Computer Society NET3.039
Initializing RT netlink socket

(I don't know whether not having /proc mounted in the chroot could
causes problems),

Sincerely,

Adrian Phillips

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