Re: kern/55611: sn_opencount wrong

[Martin Husemann <martin%duskware.de@localhost>]

The following reply was made to PR kern/55611; it has been noted by GNATS.

From: Martin Husemann <martin%duskware.de@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: kern/55611: sn_opencount wrong
Date: Sat, 17 Jul 2021 18:34:49 +0200

 I modified the KASSERT to show the vnode and opencount and got this:
 
 [ 274.3503751] panic: kernel diagnostic assertion "sn->sn_opencnt == 0" failed: file "../../../../miscfs/specfs/spec_vnops.c", line 415 vnode 0x10af4c00 sn_opencnt 4294967295
 
 [ 274.3503751] cpu0: Begin traceback...
 [ 274.3503751] 0x1072eb40: at vpanic+0x12c
 [ 274.3503751] 0x1072eb70: at kern_assert+0x60
 [ 274.3503751] 0x1072ebb0: at spec_node_revoke+0x10c
 [ 274.3503751] 0x1072ebd0: at vcache_reclaim+0x6a4
 [ 274.3503751] 0x1072ec60: at vgone+0x114
 [ 274.3503751] 0x1072ec80: at vrevoke+0x114
 [ 274.3503751] 0x1072ecb0: at genfs_revoke+0x1c
 [ 274.3503751] 0x1072ecc0: at VOP_REVOKE+0x48
 [ 274.3503751] 0x1072ece0: at exit1+0x794
 [ 274.3503751] 0x1072ed90: at sigexit+0x1f4
 [ 274.3503751] 0x1072edc0: at postsig+0x288
 [ 274.3503751] 0x1072ee70: at lwp_userret+0x204
 [ 274.3503751] 0x1072eeb0: at syscall+0x528
 [ 274.3503751] 0x1072ef20: user SC trap #449 by 0xfdc208d4: srr1=0x200d032
 [ 274.3503751]             r1=0xffffe450 cr=0x42082222 xer=0x20000000 ctr=0xfdc208d0
 [ 274.3503751] cpu0: End traceback...
 Stopped in pid 895.895 (login) at       netbsd:vpanic+0x130:    or      r3, r26,
  r26
 db{0}> show vnode 0x10af4c00
 OBJECT 0x10af4c00: locked=0, pgops=0xb7d2fc, npages=0, refs=1
 
 vnode 0x10af4c00 flags 0x8014<ISTTY,MPSAFE>
 tag VT_NON(0) type VCHR(4) mount 0x5fb0f000 typedata 0x1037b240
 usecount 1 writecount 0 holdcount 0
 size 0 writesize 0 numoutput 0
 data 0x0 lock 0x10af4d40
 state RECLAIMING key(0x5fb0f000 0)
 lrulisthd 0xc0fa08
 
 
 I can still reproduce it "often" on this particular machine.
 
 Martin