[uml-devel] How to reproduce my race condition.

[Rob L. <ro...@la...>]

Here's what I do:

Grab the binaries tarball from http://www.landley.net/code/firmware/broken.tbz 
(this is about 650k compressed, and 1.3 megs uncompressed).

Extract it, and remember where it is.

Build UML, as follows:

tar xvjf linux-2.6.13.2.tar.bz2
cd linux-2.6.13.2
make ARCH=um allnoconfig
cat >> .config << EOF
CONFIG_MODE_SKAS=y
CONFIG_BINFMT_ELF=y
CONFIG_HOSTFS=y
CONFIG_STDERR_CONSOLE=y
CONFIG_UNIX98_PTYS=y
CONFIG_BLK_DEV_LOOP=y
CONFIG_LBD=y
CONFIG_PROC_FS=y
EOF
yes "" | make ARCH=um oldconfig
make ARCH=um

Run this UML via:

./linux rootfstype=hostfs  rw init=/bin/sh LD_ASSUME_KERNEL=2.4.1

And now run the test:

chroot /path/to/broken /test.sh

An example run on my laptop:

chroot /home/landley/newbuild/firmware-build-0.8.1/broken /test.sh
/busybox install -c test.sh /sub/1
/busybox install -c test.sh /sub/2
/busybox install -c test.sh /sub/3
/busybox install -c test.sh /sub/4
/busybox install -c test.sh /sub/5
/busybox install -c test.sh /sub/6
/busybox install -c test.sh /sub/7
/busybox install -c test.sh /sub/8
/busybox install -c test.sh /sub/9
/busybox install -c test.sh /sub/10
/busybox install -c test.sh /sub/11
/busybox install -c test.sh /sub/12
/busybox install -c test.sh /sub/13
install: unable to open `/sub/13/test.sh': No such file or directory
install: cannot change permissions of /sub/13/test.sh: No such file or 
directory
install: cannot change ownership of /sub/13/test.sh: No such file or directory
sh-3.00#                       


It's possible that busybox or uClibc is doing something wrong, but this is 
_rock_solid_ on a normal kernel, and on 2.6.11-um (under -tt mode, anyway).  
On 2.6.13, this happens in both -tt mode and -skas0 mode.

Help?

Rob