kern/151941: FreeBSD RELENG_6 server freezes during create of a snapshot on a disk with mpt

[Remko Lodder]

The following reply was made to PR kern/151941; it has been noted by GNATS.

From: Remko Lodder <remko at elvandar.org>
To: Andreas Longwitz <longwitz at incore.de>
Cc: freebsd-gnats-submit at FreeBSD.org
Subject: Re: kern/151941: FreeBSD RELENG_6 server freezes during create of a snapshot on a disk with mpt
Date: Thu, 4 Nov 2010 17:20:18 +0100

 Hello Andreas,
 
 Can you please confirm that this also occurs on later versions? 6 is =
 near end of life, and given the timeframe I doubt it would be feasible =
 to look at this
 just for 6.x. BUT if this also occurs on later versions, then it has =
 more weight in the scale and is viable for investigation.
 
 Thanks
 Remko
 
 On Nov 4, 2010, at 4:56 PM, Andreas Longwitz wrote:
 
 >=20
 >> Number:         151941
 >> Category:       kern
 >> Synopsis:       FreeBSD RELENG_6 server freezes during create of a =
 snapshot on a disk with mpt
 >> Confidential:   no
 >> Severity:       critical
 >> Priority:       medium
 >> Responsible:    freebsd-bugs
 >> State:          open
 >> Quarter:       =20
 >> Keywords:      =20
 >> Date-Required:
 >> Class:          sw-bug
 >> Submitter-Id:   current-users
 >> Arrival-Date:   Thu Nov 04 16:00:19 UTC 2010
 >> Closed-Date:
 >> Last-Modified:
 >> Originator:     Andreas Longwitz
 >> Release:        RELENG_6
 >> Organization:
 > Data Service Stockelsdorf
 >> Environment:
 > FreeBSD dssbkp1.incore 6.4-STABLE FreeBSD 6.4-STABLE #2: Wed Nov  3 =
 18:18:31 CET 2010     =
 root at dssbkp1.incore:/usr/src/sys/i386/compile/SERVER  i386
 >> Description:
 > An actual FreeBSD RELENG_6 system stops working on the command
 >      mount -u -o snapshot /prod/.snap/fscktest prod
 > where prod is a 1 TB partition on a scsi disk /dev/da0p1 connected
 > to mpt. The machine is semi-dead: All user processes are sleeping,
 > all cpus idle, only ping and ddb is possible. Giant is the only lock
 > shown by ps in ddb. The trace of the mount process causing the problem
 > looks like this:
 >=20
 > Tracing command mount pid 7871 tid 100190 td 0xd1070480
 > sched_switch(d1070480,0,1) at sched_switch+0x14b
 > mi_switch(1,0,d1070480,f3408348,c03e6d10,...) at mi_switch+0x1ba
 > sleepq_switch(c0631cc4) at sleepq_switch+0x87
 > sleepq_wait(c0631cc4,0,d1070480,4,0,...) at sleepq_wait+0x5c
 > msleep(c0631cc4,c0631ce0,50,c05b02c2,0) at msleep+0x269
 > getnewbuf(0,0,4000,4000) at getnewbuf+0x6ce
 > getblk(d08de440,4cb7f440,0,4000,0,...) at getblk+0x360
 > breadn(d08de440,4cb7f440,0,4000,0,...) at breadn+0x31
 > bread(d08de440,4cb7f440,0,4000,0,f34084a8) at bread+0x20
 > ffs_alloccg(d134cad4,d5c,132dfce8,0,4000) at ffs_alloccg+0x13d
 > ffs_hashalloc(d134cad4,d5c,132dfce8,0,4000,...) at ffs_hashalloc+0x28
 > =
 ffs_alloc(d134cad4,281ec6f,0,132dfce8,0,4000,d051d400,f34085e8,d134cad4,28=
 1ec6f,0,463,e8cae000)  =20
 > at ffs_alloc+0x20d
 > ffs_balloc_ufs2(d12dd880,7b1bc000,a0,4000,d051d400,0,f34087d8) at =
 ffs_balloc_ufs2+0x16fc
 > ffs_snapshot(d099a2bc,d130e8a0,d130e8a0,d0982600,d08de440,...) at =
 ffs_snapshot+0x89b
 > ffs_mount(d099a2bc,d1070480,10201000,0,d0520a80,...) at =
 ffs_mount+0x991
 > vfs_domount(d1070480,d1125750,d0f8a250,11010000,d1125330) at =
 vfs_domount+0x728
 > vfs_donmount(d1070480,11010000,f3408c04) at vfs_donmount+0x415
 > kernel_mount(d06599c0,11010000,804e040,0,fffffffe,...) at =
 kernel_mount+0x38
 > ffs_cmount(d06599c0,bf7fdec0,11010000,d1070480,c05f84e0,...) at =
 ffs_cmount+0x5d
 > mount(d1070480,f3408d04) at mount+0x18e
 > syscall(3b,3b,3b,804af21,bf7fe974,...) at syscall+0x2bf
 > Xint0x80_syscall() at Xint0x80_syscall+0x1f
 > --- syscall (21, FreeBSD ELF32, mount), eip =3D 0x880bfbcb, esp =3D =
 0xbf7fde9c, ebp =3D 0xbf7fdf38 ---
 >=20
 > The problem arises both on i386 and amd64 server. Creating snapshots =
 an 300 GB disks connected to amr controller work without any problems.
 >> How-To-Repeat:
 > see above
 >> Fix:
 > The reason for the problem is the update from 1.50.2.2 to 1.50.2.3 of =
 the source ffs_balloc.c (SVN rev 196973 on 2009-09-08 14:19:14; MFC =
 r180758).
 > If I revert this change from the kernel the problem disappears.
 >=20
 >> Release-Note:
 >> Audit-Trail:
 >> Unformatted:
 > _______________________________________________
 > freebsd-bugs at freebsd.org mailing list
 > http://lists.freebsd.org/mailman/listinfo/freebsd-bugs
 > To unsubscribe, send any mail to =
 "freebsd-bugs-unsubscribe at freebsd.org"
 >=20
 
 --=20
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