panic: condition seqc_in_modify(_vp->v_seqc) not met at zfs_acl.c:1147 (zfs_acl_chown_setattr)

I've got this panic once when copying a couple of files.
The system is stable/13 as of 1996360d7338d, a custom kernel configuration, but
no local source code modifications.

Unread portion of the kernel message buffer:
VNASSERT failed: ({ seqc_t __seqc = (_vp->v_seqc); __builtin_expect((__seqc &
1), 0); }) not true at
/usr/devel/git/trant/sys/contrib/openzfs/module/os/freebsd/zfs/zfs_acl.c:1147
(zfs_acl_chown_setattr)
0xfffff8013e4e85b8: type VDIR
    usecount 1, writecount 0, refcount 1 seqc users 0 mountedhere 0
    hold count flags ()
    flags ()
    lock type zfs: EXCL by thread 0xfffffe01dd1cd560 (pid 30747, kdeinit5, tid
159911)
panic: condition seqc_in_modify(_vp->v_seqc) not met at
/usr/devel/git/trant/sys/contrib/openzfs/module/os/freebsd/zfs/zfs_acl.c:1147
(zfs_acl_chown_setattr)

Any ideas, suggestions, hints?
Thanks!

(kgdb) #0  doadump (textdump=textdump_at_entry=1)
    at /usr/devel/git/trant/sys/kern/kern_shutdown.c:399
#1  0xffffffff8083bea2 in kern_reboot (howto=260)
    at /usr/devel/git/trant/sys/kern/kern_shutdown.c:486
#2  0xffffffff8083c4f7 in vpanic (
    fmt=0xffffffff80c33e58 "condition %s not met at %s:%d (%s)",
    ap=0xfffffe029a36c2c0)
    at /usr/devel/git/trant/sys/kern/kern_shutdown.c:919
#3  0xffffffff8083c0a3 in panic (fmt=<unavailable>)
    at /usr/devel/git/trant/sys/kern/kern_shutdown.c:843
#4  0xffffffff8036fd21 in zfs_acl_chown_setattr (zp=0xfffff801ccd203b0)
    at /usr/devel/git/trant/sys/contrib/openzfs/module/os/freebsd/zfs/zfs_acl.c:1147
#5  0xffffffff8037e52d in zfs_setattr (zp=0xfffff8024b04f760,
    vap=vap_at_entry=0xfffffe029a36c870, flags=flags_at_entry=0,
    cr=<optimized out>, cr_at_entry=0xfffff8003ecedc00)
    at
/usr/devel/git/trant/sys/contrib/openzfs/module/os/freebsd/zfs/zfs_vnops_os.c:2758
#6  0xffffffff803817ee in zfs_freebsd_setattr (ap=<optimized out>)
    at
/usr/devel/git/trant/sys/contrib/openzfs/module/os/freebsd/zfs/zfs_vnops_os.c:4918
#7  0xffffffff80ba6087 in VOP_SETATTR_APV (
    vop=0xffffffff80e59280 <zfs_vnodeops>, a=a_at_entry=0xfffffe029a36ca00)
    at vnode_if.c:927
#8  0xffffffff80915a89 in VOP_SETATTR (vp=vp_at_entry=0xfffff8016524d5b8,
    vap=vap_at_entry=0xfffffe029a36ca30, cred=<unavailable>,
    cred_at_entry=0xfffff8003ecedc00) at ./vnode_if.h:485
#9  0xffffffff80915d67 in setfown (td=<optimized out>,
    cred=0xfffff8003ecedc00, vp=0xfffff8016524d5b8, uid=uid_at_entry=4294967295,
    gid=gid_at_entry=20) at /usr/devel/git/trant/sys/kern/vfs_syscalls.c:2942
#10 0xffffffff80915eb6 in kern_fchownat (td=0xfffffe01dd1cd560,
    fd=fd_at_entry=-100,
    path=0x803697858 <error: Cannot access memory at address 0x803697858>,
    pathseg=pathseg_at_entry=UIO_USERSPACE, uid=-1, gid=<unavailable>, flag=0)
    at /usr/devel/git/trant/sys/kern/vfs_syscalls.c:3002
#11 0xffffffff80915db6 in sys_chown (td=<unavailable>, uap=<optimized out>)
    at /usr/devel/git/trant/sys/kern/vfs_syscalls.c:2962
#12 0xffffffff80b25b69 in syscallenter (td=0xfffffe01dd1cd560)
    at /usr/devel/git/trant/sys/amd64/amd64/../../kern/subr_syscall.c:189
#13 0xffffffff80b25845 in amd64_syscall (td=0xfffffe01dd1cd560, traced=0)
    at /usr/devel/git/trant/sys/amd64/amd64/trap.c:1156

-- 
Andriy Gapon