You may experience so called deadlocks, the situation where
a system stops doing useful work. To provide a helpful bug report
in this situation, use ddb(4) as described above.
Include the output of ps
and
trace
for suspected processes in the
report.
If possible, consider doing further investigation. The receipt below is especially useful if you suspect that a deadlock occurs in the VFS layer. Add the following options
to the kernel configuration file. When a deadlock occurs, in addition to the
output of the ps
command, provide information
from the show pcpu
, show allpcpu
,
show locks
, show alllocks
,
show lockedvnods
and alltrace
.
To obtain meaningful backtraces for threaded processes, use
thread thread-id
to switch to the thread
stack, and do a backtrace with where
.
This, and other documents, can be downloaded from http://ftp.FreeBSD.org/pub/FreeBSD/doc/
For questions about FreeBSD, read the
documentation before
contacting <questions@FreeBSD.org>.
For questions about this documentation, e-mail <doc@FreeBSD.org>.