Re: df stuck in tstile

[christos%zoulas.com@localhost (Christos Zoulas)]

On Jan 30,  4:14pm, steve%prd.co.uk@localhost (Steve Blinkhorn) wrote:
-- Subject: Re: df stuck in tstile

| I think I'm probably out of my depth on this one.  I used to get this
| kind of problem on the machines these replace, and became convinced
| that that was a bad block issue (which got aired on one lof the other
| lists - they were x86 macnines).  Once there was one process stuck in
| tstile, the problem began to accumulate, and the only solution was a
| periodic reboot.  IIRC the problem started with a df.
| 
| Unfortunately, the version of crash(8) that came with 8.0_RC1 won't work.
| They were clean istallations onto brand-new machines, but I get a
| "versioins differ" error message when I run crash.

It should work anyway (they are close and it is a warning),
versions does not matter much.

| But I don't really have a handle on what might be going on - I can
| only guess at what tstile might be, and suppose it is some kind of
| queuing mechanism in the kernel.   Is there any way of killing a
| process that gets stuck in this way?  kill -9 does nothing, and
| killing the parent process just means that the stuck process is
| parented directly by process 1.
| 
| These servers are providing services to customers around the clock
| (the live service is not actually impacted), and live in a data
| centre, so I need to understand the nature of the problem before I
| start makiang changes that would lead to down time.

Crash will not affect anything (it is perfectly safe unless you
try to modify things). You can just 

[1:06pm] 145#ps -ax | tail -1
  581 ttyE3  Is+     0:00.00 /usr/libexec/getty Pc ttyE3 
[1:06pm] 146#crash
Crash version 7.99.59, image version 7.99.59.
Output from a running system is unreliable.
crash> t/t 0t581
trace: pid 581 lid 1 at 0xfffffe8158cb3b40
sleepq_block() at sleepq_block+0xa0
cv_timedwait_sig() at cv_timedwait_sig+0x107
ttysleep() at ttysleep+0x7c
ttread() at ttread+0x296
cdev_read() at cdev_read+0x70
spec_read() at spec_read+0xc3
VOP_READ() at VOP_READ+0x37
vn_read() at vn_read+0x94
dofileread() at dofileread+0x8f
sys_read() at sys_read+0x5f
syscall() at syscall+0x1d2
--- syscall (number 3) ---
7746cfe3deda:
crash> q
[1:06pm] 147#

christos