[dm-devel] Possible bug in multipathd (getting a segfault)

[S. J. van Harmelen]

On Tue, 2007-11-20 at 12:15 +0100, Tore Anderson wrote:
> * S. J. van Harmelen
> 
> > I guess I don't have to do that as I compiled the multipath-tools 
> > myself?
> 
> Then you should have the debugging symbols in place, yes.
> 
> > I did compile them when running the 2.6.22.2 kernel though. Should I 
> > recompile them when running the 2.6.23.1 kernel, or doesn't that
> > matter?
> 
> Doesn't matter.
> 
> > Oke, the segfault happens right at the start (and only at the start),
> > so that shouldn't be a problem. But I have to stop the running
> > mulipathd and that seems like a problem. This machine is running in
> > production :)
> > 
> > So that will have to wait until I get a maintance window I guess...
> 
> Stopping multipathd isn't problematic.  It is only responsible for
> periodically testing paths to pre-emptively fail non-active paths or
> re-instate paths that has been failed by the kernel's dm-multipath layer.
> 
> If everything is running stable with all paths alive and well,
> restarting multipathd is nothing to worry about.

I tried it, but it doesn't give me a core dump. It only shows one line
in syslog for each time that I start multipathd. Multipathd keeps
running with no noticeable errors though.

I'm running the system with a 2.6.23.8 kernel and it shows this error
one time per start of multipathd:

kernel: multipathd[2303]: segfault at 000000000000000a rip
00002baa8765f94f rsp 00007fff23b8e370 error 4
kernel: multipathd[3742]: segfault at 000000000000000a rip
00002b09ff82394f rsp 00007fffab9ca130 error 4
kernel: multipathd[4103]: segfault at 000000000000000a rip
00002adefdbe894f rsp 00007fffad604d90 error 4

Also I noticed that I get the "DELL     ,Universal Xpor" in my multipath
-ll output. Didn't get that before. Is that something to look at?

root at storage:~# multipath -ll
360019b9000d7e1100000000000000000dm-5 DELL    ,Universal Xpor
[size=20M][features=0][hwhandler=0]
\_ round-robin 0 [prio=1][enabled]
 \_ 1:0:0:31 sdf 8:80  [active][ready]
backup (360019b9000d7e1100000444b46be82c4) dm-2 DELL    ,MD3000        
[size=200G][features=0][hwhandler=1 rdac]
\_ round-robin 0 [prio=3][active]
 \_ 1:0:1:2  sdi 8:128 [active][ready]
\_ round-robin 0 [prio=0][enabled]
 \_ 1:0:0:2  sdd 8:48  [active][ghost]
xen (360019b9000d7e11000004485473faa94) dm-1 DELL    ,MD3000        
[size=200G][features=0][hwhandler=1 rdac]
\_ round-robin 0 [prio=3][enabled]
 \_ 1:0:0:3  sde 8:64  [active][ready]
\_ round-robin 0 [prio=0][enabled]
 \_ 1:0:1:3  sdj 8:144 [active][ghost]
360019b9000d7ddab0000000000000000dm-0 DELL    ,Universal Xpor
[size=20M][features=0][hwhandler=0]
\_ round-robin 0 [prio=1][enabled]
 \_ 1:0:1:31 sdk 8:160 [active][ready]
vmware (360019b9000d7e1100000444846be81b6) dm-4 DELL    ,MD3000        
[size=200G][features=0][hwhandler=1 rdac]
\_ round-robin 0 [prio=3][enabled]
 \_ 1:0:0:0  sdb 8:16  [active][ready]
\_ round-robin 0 [prio=0][enabled]
 \_ 1:0:1:0  sdg 8:96  [active][ghost]
data (360019b9000d7ddab0000493846be81e5) dm-3 DELL    ,MD3000        
[size=200G][features=0][hwhandler=1 rdac]
\_ round-robin 0 [prio=3][active]
 \_ 1:0:1:1  sdh 8:112 [active][ready]
\_ round-robin 0 [prio=0][enabled]
 \_ 1:0:0:1  sdc 8:32  [active][ghost]

Regards,

Sander