Jan Engelhardt wrote: > On Feb 22 2007 14:30, Michael Tokarev wrote: >> Deepak Saxena wrote: >>> We attempted an experiment in cleaning up some modprobe messages during >>> initramfs bootup when the modules directory is missing by moving modprobe >>> to modprobe-bin and replacing modprobe with the following simple shell >>> script: >>> >>> #!/bin/sh >>> # Clean up bootup when modules are not present >>> >>> if [ -e "/lib/modules/'uname -r'/modules.dep" ] ; then >>> /sbin/modprobe-bin $* > > The nitpick guide says: `uname -r` and "$@" instead of $* ;-)
Here, it's possible to workaround the pipefs issue... with another kernel bugfix. uname -r is available in /proc/sys/kernel/version, but the problem is that reading almost any file in /proc with shell, which does read by a single byte, returns only first byte of of the file being read. The bug has been addressed by Andrew recently, but I don't remember if the fix is in 2.6.20 or 2.6.19.x yet. I discovered it exactly because of this very issue - hit pipefs bug and tried to work around it by replacing the above construct with read version < /proc/sys/kernel/version ... /lib/modules/$version/modules.dep ... wich results in $version being set to.. "2" (from "2.6...." :) But sure, the usage is wrong, albiet ok for some minimal debugging. >>> BUG: unable to handle kernel NULL pointer dereference at virtual address >>> 00000014 >>> Trace; c0107737 <sys_pipe+17/60> >> This is the same issue I reported much earlier with /sbin/hotplug being a >> script >> in initrfamfs. The problem is because pipefs isn't initialized yet at the >> time >> the script gets called, and causes a NULL-pointer deref. Obviously you're >> using >> pipe above. > > Btw, has this pipefs issue been adressed (by moving pipefs before initramfs > stage), or something? Not as I know of. It has been discussed, but seems to be of low priority. At least, reading /proc file is fixed... somewhere... :) So it's now possible to work around it, at least in some places (because sometimes pipe is really useful anyway and difficult to substitute with something ;) /mjt - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
