System hangs when /var partition full (vnode_pager_putpages errors)
Maks Verver
m.verver at student.utwente.nl
Thu Apr 3 20:41:28 UTC 2008
Hi,
I recently encountered an error, where executing the ImageMagick "convert"
tool as an unpriviliged user caused the system to hang.
The error is similar to one reported in 2004:
http://lists.freebsd.org/mailman/htdig/freebsd-stable/2004-March/006493.html
There is also an open bug report:
http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/67919
I'll give some more details on my situation, although it's really very similar
to the one described on the mailing list. I use ImageMagick to resample a
300kb 1024x768 resolution JPEG file to 800x600, which causes ImageMagick to
create a temporary file (not sure how large, sorry) in /var/tmp.
The /var paritition does not have enough space apparently, and the system
hangs, while printing repeatedly:
kernel: vnode_pager_putpages: I/O error 28
kernel: vnode_pager_putpages: residual I/O 65536 at 74284
kernel: pid 42 (syncer), uid 0 inumber 70779 on /var: filesystem full
At this point, the system still responds to ping, but anything else
(presumable anything involving disk I/O) is impossible, including logging in
locally. (In the previous discussion it was suggested that the hang-up was
actually caused by the amount of messages being printed, but this is not the
case, as in FreeSD 7 these messages are printed only once each second.)
The bug report is from 2004 (last modified in 2005); is there any chance this
will be resolved in the future? I can work around it temporarily by ensuring
there is enough space on /var (and using ulimit when I invoke convert) but it
still means that any malevolent user can crash the system. That's the kind of
shenanigans I'd expect on a Linux system ;-) not on FreeBSD which is usually
very stable.
To summarize: are people aware this problem still exists, is it recognized as
an important issue, and are there plans to fix it?
Kind regards,
Maks Verver.
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