Re: Patch (repost): cramfs memory corruption fix

David L. Parsley (parsley@linuxjedi.org)
Sun, 07 Jan 2001 15:39:52 -0500


Alan Cox wrote:
> -ac has the rather extended ramfs with resource limits and stuff. That one
> also has rather more extended bugs 8). AFAIK none of those are in the vanilla
> ramfs code

Nifty stuff, too; it's nice for a ramfs mount to show up in 'df' with
useful figures. Shame I can't put anything there. ;-)

2.4.0 ramfs with the one-liner does it's job for me already; what I'd
really love to fool with is _cramfs_. ;-) In case you missed the
beginning of this thread: all my cramfs initrd's fail to mount as
/dev/ram0 with 'wrong magic'; their romfs counterparts work fine. I did
manage to pivot_root into a cramfs root, but it blew up pretty quick
with 'attempt to access beyond end of device', and killed my init
shell. Then there's the wierdness where cramfs compiled in the kernel
corrupts the romfs. Adam's one-liner (bforget -> brelse on superblock)
didn't fix this.

The cramfs docs are contradictory btw; the kernel help says 'doesn't
support hardlinks', and Documentation/filesystems/cramfs.txt says
'Hardlinks are supported, but...'. I made my cramfs with and without
hardlinks (to busybox); but that didn't affect whether it mounted. I
haven't tested whether this fixes the 'access beyond end of device'
problems.

regards,
David

-- 
David L. Parsley
Network Administrator
Roanoke College
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