[9fans] ramfs, lib9p

[Martin Wyser <martin.wyser@inf.ethz.ch>]

Boys, and of course Girls too:

I noticed that there are two ramfs implementations:
/sys/src/cmd/ramfs.c    seems old, because does not use lib9p
/sys/src/lib9p/ramfs.c  seems newer, because does use lib9p

Unfortunately, both have bad bugs.  I would suggest dumping the old one, 
  and in that spirit started looking at the problems with the newer.

I did
cd /tmp
mkdir ramfs
8c /sys/src/lib9p/ramfs.c
8l -o ramfs ramfs.8
./ramfs -s ramfs
mount -c /srv/ramfs /tmp/ramfs
unmount /tmp/ramfs
mount -c /srv/ramfs /tmp/ramfs   #again
ls /tmp/ramfs   #crashes nicely

So I started looking through it, and it looks like the problems are in 
lib9p.  Where to send my findings?  Discuss them here?
(I checked with sources and found that I am up-to-date).

kind regards, Martin

With some -D and acid, I got the following information:
-----
<-5- Tversion tag 65535 msize 8216 version '9P2000'
-5-> Rversion tag 65535 msize 8216 version '9P2000'
<-5- Tauth tag 3 afid 211 uname mwyser aname
-5-> Rerror tag 3 ename ./ramfs: authentication not required
<-5- Tattach tag 3 fid 211 afid -1 uname mwyser aname
-5-> Rattach tag 3 qid (0000000000000000 0 d)
<-5- Tclunk tag 3 fid 211
-5-> Rclunk tag 3
<-5- Tauth tag 3 afid 208 uname mwyser aname
-5-> Rerror tag 3 ename ./ramfs: authentication not required
<-5- Tattach tag 3 fid 208 afid -1 uname mwyser aname
-5-> Rattach tag 3 qid (0000000000000000 0 d)
<-5- Twalk tag 3 fid 208 newfid 212 nwname 0
-5-> Rwalk tag 3 nwqid 0
<-5- Tstat tag 3 fid 212
-5-> Rstat tag 3  stat 'mwyser' '\x03' 'mwyser' 'mwyser' q 
(0000000000000000 0 d) m 020000000777 at 1083085032 mt 1083085032 l 0 t 
0 d 0
<-5- Tclunk tag 3 fid 212
-5-> Rclunk tag 3
panic: D2B called on non-block 18394 (double-free?) (magic 00000000)
ramfs 122: suicide: sys: trap: fault read addr=0x0 pc=0x00004b63

acid: stk()
abort()+0x0 /sys/src/libc/9sys/abort.c:6
ppanic(p=0x17d5c,fmt=0x17914)+0x152 /sys/src/libc/port/malloc.c:158
D2B(v=0x18394,p=0x17d5c)+0x38 /sys/src/libc/port/pool.c:944
poolfreel(v=0x18394,p=0x17d5c)+0x20 /sys/src/libc/port/pool.c:1065
poolfree(p=0x17d5c,v=0x18394)+0x41 /sys/src/libc/port/pool.c:1175
free(v=0x1839c)+0x23 /sys/src/libc/port/malloc.c:228
fsdestroyfile(f=0x18330)+0x29 /usr/mwyser/ramfs/ramfs.c:111
closefile(f=0x18330)+0x23 /sys/src/lib9p/file.c:75
closefid(f=0x1d808)+0x5f /sys/src/lib9p/fid.c:71
closereq(r=0x1d428)+0x77 /sys/src/lib9p/req.c:79
respond(error=0x0,r=0x1d428)+0x31f /sys/src/lib9p/srv.c:803
sclunk(srv=0x1306c,r=0x1d428)+0x51 /sys/src/lib9p/srv.c:548
srv(srv=0x1306c)+0x1be /sys/src/lib9p/srv.c:702
_post2(v=0x1306c)+0x4f /sys/src/lib9p/_post.c:41
postmountsrv(s=0x1306c,name=0x7fffeff6,mtpt=0x0,flag=0x4)+0x5e 
/sys/src/lib9p/post.c:19
main(argv=0x7fffefe0,argc=0x0)+0x105 /usr/mwyser/ramfs/ramfs.c:162
_main+0x31 /sys/src/libc/386/main9.s:16
acid:
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