[OpenAFS-devel] deadlock on linux-2.4

[Neulinger, Nathan]

I am able to confirm this - but only on a UP machine, does not occur for
me on an SMP system.

srvtst02: 1-CPU, SMP-2.4.18 kernel
	locks up as N=3D3
srvtst07: 2-CPI, SMP-2.4.18 kernel
	never locks up for me, at least not into N=3D2000+

(Yes, the UP box is running an SMP kernel. We do that so we can have a
common kernel for all installs when possible.)

I'm running the protos branch of cvs.=20

-- Nathan

------------------------------------------------------------
Nathan Neulinger                       EMail:  nneul@umr.edu
University of Missouri - Rolla         Phone: (573) 341-4841
Computing Services                       Fax: (573) 341-4216


> -----Original Message-----
> From: Pavel Semerad [mailto:semerad@ss1000.ms.mff.cuni.cz]=20
> Sent: Monday, June 03, 2002 12:25 PM
> To: openafs-devel@openafs.org
> Subject: [OpenAFS-devel] deadlock on linux-2.4
>=20
>=20
>=20
> Hi,
> there is a deadlock situation in openafs for linux-2.4 (at least in
> vanilla kernel 2.4.18 and CVS openafs version). linux-2.2, Solaris 8
> and Irix 6.5 seems to be OK.
> Alias mc from RedHat 7.3 sometimes caused it when exiting mc. And this
> command causes it:
>=20
> N=3D0; while true; do N=3D$(($N+1)); echo $N; (cp /etc/profile=20
> aaa &); cat aaa >/dev/null; done
>=20
> Here is a cmdebug output:
> ---
> ** Cache entry @ 0xc49a57d8 for 1.536877573.514.10221
> locks: (writer_waiting, upgrade_locked(pid:1334 at:121), 1=20
> read_locks(pid:1395), 2 waiters)
> 1003 bytes  DV 4329 refcnt 2
> callback c36c9100   expires 1023138509
> 2 opens     1 writers
> normal file
> states (0x21), stat'd
> ---
> pid 1334 is afsd, 1395 is cat
>=20
> afsd is holding shared lock on vcache->lock and is trying to=20
> obtain write lock
> in afs/afs_segments.c line 542 .
> cat called afs_UFSRead, there obtains read lock and called=20
> afs_GetDCache and
> then somewhere locks. I don't know where. Can it be linux-2.4=20
> VM issue, or
> somebody has any ideas ?
>=20
> Pavel Semerad
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>=20