Thank you for looking after my problem.

As Ori asked, here is a stack trace from the probably hanging thread.

/proc/504/text:amd64 plan 9 executable
/sys/lib/acid/port
/sys/lib/acid/amd64
acid: lstk()
pread(a0=0x4)+0xe /sys/src/libc/9syscall/pread.s:6
read(buf=0x44f158,n=0x4)+0x27 /sys/src/libc/9sys/read.c:7
readn(n=0x4,f=0x4,av=0x44f158)+0x42 /sys/src/libc/port/readn.c:13
a=0x44f158
t=0x0
read9pmsg(abuf=0x44f158,fd=0x4,n=0xfefefefe00004018)+0x25 /sys/src/libc/9sys/read9pmsg.c:14
buf=0x44f158
len=0x44eeb8
msgRead(v=0x436c40)+0x71 /sys/src/cmd/fossil/9proc.c:364
con=0x436c40
fd=0x4
eof=0x436c4000000000
m=0x44eeb8
n=0x4fefefefe
launcheramd64(arg=0x436c40,f=0x2063dd)+0x10 /sys/src/libthread/amd64.c:11
0xfefefefefefefefe ?file?:0

The n parameter in read9pmsg() looks weird.

FYI, I also add the fossil conf :

fsys main config
fsys main open
fsys main
venti 192.168.44.16
srv -p fscons
srv fossil
listen tcp!*!9fs
srv -AWP fossilAWP