Bug: sync's hangup forever in call_rwsem_down_read_failed
Date: Tue Nov 23 2010 - 10:49:30 EST
on 2.6.37-rc2 I was doing some speed tests. I had just unmounted various
arrays, recreated them differently with mdadm assume-clean, and then I
was formatting all of them:
# for i in /dev/md10* ; do echo $i ; time mkfs.ext4 -m0 $i ; time sync ;
mke2fs 1.41.9 (22-Aug-2009)
/dev/md101 is apparently in use by the system; will not make a
Here I was pretty sure the error message was wrong: md101 was not in use
by the system anyhow, and was not mounted. I had just created it.
Anyway the subsequent sync hanged!
# cat /proc/7686/stack
After a while I tried to launch another sync, from another shell; that
/proc# grep call_rwsem */stack
(this shows only the two syncs)
Then I tried to shut it down with poweroff -f (which does sync) and that
/proc# grep rwsem */stack
so I shut it down with poweroff -n -f ; that worked.
It seems to me some process did not reset the semaphore after having
finished (= resource leak)
Sorry for not being able to help you much more than this as I have reset
the computer now, but this is another guy reporting apparently the same
problem on Ubuntu 10.10 kernel (I was on vanilla 2.6.37-rc2)
My dmesg never notified about the problem, in something like 5minutes, btw.
If you reply, please reply also to me as I am not subsribed to
Thanks for your work
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