Strange FreeBSD lock (related to iSCSI initiator connected to NetBSD istgt ?)

	Hello,

	On my network, all workstations are diskless (Linux, FreeBSD, NetBSD,
even OpenVMS). Main server runs NetBSD 10.0 and acts as:
- boot server
- nfs server (/ and /home)
- iSCSI (for swap)

	Pythagore runs FreeBSD 14.0 and is a diskless workstation.
	Legendre runs NetBSD 10.0 and is network's main server.

	FreeBSD workstation randomly hangs. On server side, I can see in this
workstation's logfile:

Jul 15 15:54:16 pythagore kernel: WARNING: 192.168.10.128
(iqn.2020-02.fr.systella.legendre.istgt:pythagore): no ping reply
(NOP-In) after 5 seconds; reconnecting
Jul 15 15:54:31 pythagore kernel: swap_pager: indefinite wait buffer:
bufobj: 0, blkno: 3242023, size: 32768
Jul 15 15:54:32 pythagore kernel: swap_pager: indefinite wait buffer:
bufobj: 0, blkno: 3295147, size: 8192
Jul 15 15:54:32 pythagore kernel: swap_pager: indefinite wait buffer:
bufobj: 0, blkno: 3294054, size: 24576
Jul 15 15:54:32 pythagore kernel: swap_pager: indefinite wait buffer:
bufobj: 0, blkno: 2691989, size: 4096
Jul 15 15:54:33 pythagore kernel: swap_pager: indefinite wait buffer:
bufobj: 0, blkno: 3185488, size: 4096
Jul 15 15:54:33 pythagore kernel: swap_pager: indefinite wait buffer:
bufobj: 0, blkno: 3244176, size: 4096
Jul 15 15:54:33 pythagore kernel: swap_pager: indefinite wait buffer:
bufobj: 0, blkno: 1477832, size: 12288
...
Jul 15 15:55:17 pythagore kernel: WARNING: 192.168.10.128
(iqn.2020-02.fr.systella.legendre.istgt:pythagore): login timed out
after 61 seconds; reconnecting
...

	OK. I understand. iSCSI FreeBSD client was disconnected and, as FreeBSD
tries to do some operation on swap, kernel hangs.

	On server side, I have :

Jul 15 15:54:17 legendre istgt[26125]: istgt_iscsi.c:
765:istgt_iscsi_read_pdu: ***ERROR*** readv() failed
(-1,errno=54,iqn.1994-09.org.freebsd:pythagore,time=0)
Jul 15 15:54:17 legendre istgt[26125]: istgt_iscsi.c:5685:worker:
***ERROR*** conn->state = 1
Jul 15 15:54:17 legendre istgt[26125]: istgt_iscsi.c:5702:worker:
***ERROR*** iscsi_read_pdu() failed
Jul 15 15:54:17 legendre istgt[26125]:
istgt_iscsi.c:1260:istgt_iscsi_write_pdu_internal: ***ERROR*** writev()
failed (errno=32,iqn.1994-09.org.freebsd:pythagore,time=0)
Jul 15 15:54:17 legendre istgt[26125]:
istgt_iscsi.c:3484:istgt_iscsi_transfer_in_internal: ***ERROR***
iscsi_write_pdu() failed
Jul 15 15:54:17 legendre istgt[26125]:
istgt_iscsi.c:3853:istgt_iscsi_task_response: ***ERROR***
iscsi_transfer_in() failed
Jul 15 15:54:17 legendre istgt[26125]: istgt_iscsi.c:5389:sender:
***ERROR*** iscsi_task_response() CmdSN=552123 failed on
iqn.2020-02.fr.systella.legendre.istgt:pythagore,t,0x0001(iqn.1994-09.org.freebsd:pythagore,i,0x80f5c96f41e6)

	All others workstations (mainly Linux and NetBSD) run without trouble.
Only FreeBSD triggers this issue. I suppose this bug is relative to
FreeBSD, but I'm not sure.

	Help to fix it will be welcome.

	Best regards,

	JB