Re: PROBLEM: FUSE unmount breaks serial terminal line

From: Miklos Szeredi
Date: Sun Aug 20 2006 - 16:55:38 EST


> something in FUSE breaks serial devices. I found this issue
> using gphotofs, don't know if any other FUSE impementation has similar
> effects. The problem is: from the moment the FUSE filesystem is unmounted,
> a process that read()s on a serial device /dev/ttyS? gets an EOF
> returncode.
>
> Here is the tail of the output from "strace -tt cat /dev/ttyS0" when the
> FUSE fs was unmounted:
>
> 19:41:46.513143 open("/dev/ttyS0", O_RDONLY|O_LARGEFILE) = 3
> 19:41:46.513373 fstat64(3, {st_mode=S_IFCHR|0660, st_rdev=makedev(4, 64), ...}) = 0
> 19:41:46.513552 read(3, "", 4096) = 0
> 19:42:49.854367 close(3) = 0
> 19:42:49.860663 close(1) = 0
> 19:42:49.860793 exit_group(0) = ?
>
> Found this on x86 with kernels 2.6.16 and 2.6.17.
>
> Any ideas?

Likely a userspace issue. Can you please attach a strace (strace -f
-p `pidof gphotofs`) to the gphotofs process just before doing the
unmount?

Thanks,
Miklos
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