Looking into PR kern/104406 it seems, that this describes exactly what I
am experiencing on three of my systems over the last weeks. They are
running FreeBSD 8.0-CURRENT (known as 7.0-CURRENT not long ago ;-) ).
On these machines I often observe hangings, sometimes only a few
seconds, on other times 20-30 seconds before input/output is back. This
seems to happen when more extensive disk usage is needed (portupgrade,
buildworld, browsing complicated websites etc.). During the hang even
xterm is not responding any more, other (diskless) applications like
xclock keep to continue. I have no panics, only UFS (and MSDOSFS) are
mounted, no NTFS. About two months ago none of my systems showed these
hangings.
I know that this 'hanging' behaviour has been described several times in
the near past on STABLE and CURRENT lists. But mostly the context was
different. In discussions beared on these hangings it seems people are
looking for misbehaviour of the scheduler (namely ULE), linux emulation,
java runtime environment or firefox. At my point of view it has more
likely to do with UFS-locking under high cpu load or something around it.
I have barely skills with programming and debuging, but if there are any
activities on this topic in the background, what can we do to help?
Sincerely,
Rainer Hurling
Oleg Derevenetz schrieb:
Can anyone take a look on PR kern/104406 ? I got repeatable hang
situation,
but I can't obtain a kernel dump to get result of all show commands
from
here:
http://www.freebsd.org/doc/en_US.ISO8859-1/books/developers-handbook/kerneldebug-deadlocks.html
After my break to debugger using Ctrl+Alt+Esc sequence and entering a
"panic" command kernel does not wrote a kernel dump but seems to hang.
Can
anyone describe how to obtain a kernel dump in this situation, or at
least
say - which output of show commands need in first place to debug this
?
Output of all suggested commands is huge and I afraid of making
mistake
when carrying this output from screen to list of paper and back :-)
This very easy to reproduce [ufs] uninterruptable deadlock
for both of RELENG_6 and RELENG_7. Look at this PR:
http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/107439
The PR is closed but the problem is still here with 7.0-PRERELEASE
and, perhaps, CURRENT.
This is probably another bug because:
1. I built kernel with INVARIANTS as described in on "Debugging Deadlocks"
page of FreeBSD Developers' Handbook and got no panic, but only deadlock;
2. I have no NTFS filesystem at all and just do a copy of file(s) from FTP
to local UFS using mc. In this PR panic occured when NTFS mounted r/w (and
NOT occured when the same NTFS mounted r/o).
--
Oleg Derevenetz <[EMAIL PROTECTED]> OOD3-RIPE
Phone: +7 4732 539880
Fax: +7 4732 531415 http://www.vsi.ru
CenterTelecom Voronezh ISP http://isp.vsi.ru
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