kern/106030: panic while rebooting with a dead disk

[Robert Watson]

The following reply was made to PR kern/106030; it has been noted by GNATS.

From: Robert Watson <rwatson at FreeBSD.org>
To: bug-followup at FreeBSD.org
Cc:  
Subject: Re: kern/106030: panic while rebooting with a dead disk
Date: Wed, 29 Nov 2006 21:51:32 +0000 (GMT)

 On Wed, 29 Nov 2006, Charlie & wrote:
 
 >> Description:
 >
 > I had a mounted ufs disk that went away. I rebooted so as to avoid a panic. 
 > Too bad. Geom paniced on me anyway:
 >
 > Syncing disks, vnodes remaining...2 (da8:isp1:0:6:2): Invalidating pack
 > g_vfs_done():da8a[WRITE(offset=81920, length=4096)]error = 6
 > panic: bundirty: buffer 0xc6d76f70 still on queue 1
 > cpuid = 0
 > KDB: enter: panic
 > [thread pid 3 tid 100000 ]
 > Stopped at      kdb_enter+0x2b: nop
 > db> bt
 > Tracing pid 3 tid 100000 td 0xc1e98000
 > kdb_enter(c0936604) at kdb_enter+0x2b
 > panic(c093f33c,c6d76f70,1,c6d76f70,cba0ec48,...) at panic+0x127
 > bundirty(c6d76f70) at bundirty+0x35
 > brelse(c6d76f70) at brelse+0x82f
 > bufdone_finish(c6d76f70) at bufdone_finish+0x34c
 > bufdone(c6d76f70) at bufdone+0xaa
 > ffs_backgroundwritedone(c6d76f70) at ffs_backgroundwritedone+0xca
 > bufdone(c6d76f70) at bufdone+0x8f
 > g_vfs_done(c21475ac) at g_vfs_done+0x8a
 > biodone(c21475ac) at biodone+0x58
 > g_io_schedule_up(c1e98000) at g_io_schedule_up+0xe6
 > g_up_procbody(0,cba0ed38) at g_up_procbody+0x5a
 > fork_exit(c067d58c,0,cba0ed38) at fork_exit+0xac
 > fork_trampoline() at fork_trampoline+0x8
 > --- trap 0x1, eip = 0, esp = 0xcba0ed6c, ebp = 0 ---
 >
 > It's unclear to me where this should be fixed. Since device invalidation is 
 > an inherently asynchronous process that could happen at any time, it seems 
 > to me that GEOM should be a bit more tolerant here.
 
 That looks a lot like a UFS/buffer cache panic, not a GEOM panic?
 
 Robert N M Watson
 Computer Laboratory
 University of Cambridge