From: Jeremie Courreges-Anglas <jca@wxcvbn.org>
Subject: Re: sys/ffs: reclaim vnode before dropping last ref
To: tech@openbsd.org
Date: Wed, 24 Jun 2026 11:53:53 +0200

On Wed, Jun 24, 2026 at 03:35:08AM -0600, Theo de Raadt wrote:
> This vrele/vgone error is safe if we want to keep everything biglock.....

For people not in the hackroom, right now a kernel with kirill's diff
breaks:

root on sd0a (6cd23ae55f48f660.a) swap on sd0b dump on sd0b
uvm_fault(0xffffef843fa328a0, 0x18, 0, 1) -> e
kernel: page fault trap, code=0
Stopped at      spec_close+0x35:        movl    0x18(%rax),%eax
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
*362332  18108      0         0x3          0    0K swapctl
spec_close(ffff8000e608aa98) at spec_close+0x35
VOP_CLOSE(ffffef83cbf32e60,4,ffffffffffffffff,ffff8000e604d238) at VOP_CLOSE+0x
59
vclean(ffffef83cbf32e60,8,ffff8000e604d238) at vclean+0x1c1
vgonel(ffffef83cbf32e60,ffff8000e604d238) at vgonel+0x63
ffs_vinit(ffff8000002f2800,ffff8000e608ac00) at ffs_vinit+0xc6
ffs_vget(ffff8000002f2800,1309a,ffff8000e608acc8) at ffs_vget+0x31f
ufs_lookup() at ufs_lookup+0xafd
VOP_LOOKUP(ffffef811f0a1510,ffff8000e608b2d0,ffff8000e608b300) at VOP_LOOKUP+0x
3f
vfs_lookup(ffff8000e608b2a0) at vfs_lookup+0x39b
namei(ffff8000e608b2a0) at namei+0x475
sys_swapctl(ffff8000e604d238,ffff8000e608b470,ffff8000e608b3f0) at sys_swapctl+
0x1db
syscall(ffff8000e608b470) at syscall+0x5d5
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x75f3ac954920, count: 2
https://www.openbsd.org/ddb.html describes the minimum info required in bug
reports.  Insufficient info makes it difficult to find and fix bugs.
ddb{0}> bo re
rebooting...

-- 
jca