Re: Ufs dead-locks on freebsd 6.2

On Thu, May 17, 2007 at 01:03:37PM -0400, Andrew Edwards wrote:
Here it is.

db> show vnode 0xccd47984
vnode 0xccd47984: tag ufs, type VDIR
usecount 5135, writecount 0, refcount 5137 mountedhere 0
flags (VV_ROOT)
v_object 0xcd02518c ref 0 pages 1
#0 0xc0593f0d at lockmgr+0x4ed
#1 0xc06b8e0e at ffs_lock+0x76
#2 0xc0739787 at VOP_LOCK_APV+0x87
#3 0xc0601c28 at vn_lock+0xac
#4 0xc05ee832 at lookup+0xde
#5 0xc05ee4b2 at namei+0x39a
#6 0xc05e2ab0 at unp_connect+0xf0
#7 0xc05e1a6a at uipc_connect+0x66
#8 0xc05d9992 at soconnect+0x4e
#9 0xc05dec60 at kern_connect+0x74
#10 0xc05debdf at connect+0x2f
#11 0xc0723e2b at syscall+0x25b
#12 0xc070ee0f at Xint0x80_syscall+0x1f

ino 2, on dev amrd0s1a
It seems to be the sort of things that cannot happen. VOP_LOCK()
returned 0, but vnode was not really locked.

Although claiming that kernel code cannot have such bug is too optimistic,
I would first make sure that:
1. You checked the memory of the machine.
2. Your kernel is built from pristine sources.


-----Original Message-----
From: Kostik Belousov [mailto:kostikbel@xxxxxxxxx]
Sent: Thursday, May 17, 2007 1:01 PM
To: Andrew Edwards
Cc: freebsd-performance@xxxxxxxxxxx; freebsd-fs@xxxxxxxxxxx
Subject: Re: Ufs dead-locks on freebsd 6.2

On Thu, May 17, 2007 at 11:44:15AM -0400, Andrew Edwards wrote:
I've upgraded to 6-stable, added the kernel options as per
the kernel
handbook. After about 5 hours of they system in a deadlock
it panic'd.
Here's the backtrace, and show pcpu, show allpcpu, show locks, show
alllocks, show lockedvnods and alltrace.

I will have the system down for approx another 15-20mins if there's
anything else someone would like while I'm in the debugger.


db> bt
Tracing pid 46784 tid 105112 td 0xd44a8000
kdb_enter(c0785f13) at kdb_enter+0x2b
vfs_badlock(c0785f2c,c0786051,ccd47984) at vfs_badlock+0x47
assert_vop_locked(ccd47984,c0786051) at assert_vop_locked+0x4a
vop_lock_post(f9f709dc,0,1002,ccd47984,f9f709f8,...) at
vop_lock_post+0x2a
VOP_LOCK_APV(c07dc2e0,f9f709dc) at VOP_LOCK_APV+0xa0
vn_lock(ccd47984,1002,d44a8000) at vn_lock+0xac
lookup(f9f70c08) at lookup+0xde
namei(f9f70c08) at namei+0x39a
unp_connect(d44b2de8,d44dc380,d44a8000,d44b2de8,25,...) at
unp_connect+0xf0
uipc_connect(d44b2de8,d44dc380,d44a8000) at uipc_connect+0x66
soconnect(d44b2de8,d44dc380,d44a8000) at soconnect+0x4e
kern_connect(d44a8000,7,d44dc380,d44dc380,0,...) at
kern_connect+0x74
connect(d44a8000,f9f70d04) at connect+0x2f
syscall(3b,805003b,bfbf003b,bfbfd920,bfbfd922,...) at syscall+0x25b
Xint0x80_syscall() at Xint0x80_syscall+0x1f

Could you, please, do the "show vnode 0xccd47984" from ddb
prompt or "p/x *(struct vnode *)0xccd47984" from kgdb using
dump for this panic ?

Side note: it seems that on HEAD, vnode_if.awk does not
generate call to vop_lock_{pre,post} due to mismatch in the
name of vop and pre/post names.



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