port-xen/60448: xl suspend: panic: kernel diagnostic assertion "incnt == __arraycount(sc->sc_ indirect)" failed

["campbell+netbsd%mumble.net@localhost via gnats" <gnats-admin%NetBSD.org@localhost>]

>Number:         60448
>Category:       port-xen
>Synopsis:       xl suspend: panic: kernel diagnostic assertion "incnt == __arraycount(sc->sc_ indirect)" failed
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-xen-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Jul 15 15:35:00 +0000 2026
>Originator:     Taylor R Campbell
>Release:        current, 11, 10, ...
>Organization:
Xen IndirectBSD Suspension, Inc.
>Environment:
>Description:
Xen guest panics on attempt to suspend:

[  66.6800723] panic: kernel diagnostic assertion "incnt == __arraycount(sc->sc_indirect)" failed: file "/home/riastradh/netbsd/current/src/sys/arch/xen/xen/xbd_xenbus.c", line 510 incnt=0 __arraycount(sc->sc_indirect)=32
[  66.6800723] cpu0: Begin traceback...
[  66.6800723] vpanic() at netbsd:vpanic+0x164
[  66.6800723] kern_assert() at netbsd:kern_assert+0x4b
[  66.6800723] xbd_xenbus_suspend() at netbsd:xbd_xenbus_suspend+0x194
[  66.6800723] device_pmf_driver_suspend() at netbsd:device_pmf_driver_suspend+0x3a
[  66.6800723] pmf_device_suspend() at netbsd:pmf_device_suspend+0x168
[  66.6800723] pmf_system_suspend() at netbsd:pmf_system_suspend+0xb9
[  66.6800723] sysctl_xen_suspend() at netbsd:sysctl_xen_suspend+0xe4
[  66.6800723] sysctl_dispatch() at netbsd:sysctl_dispatch+0xb3
[  66.6800723] sys___sysctl() at netbsd:sys___sysctl+0xca
[  66.6800723] syscall() at netbsd:syscall+0x98
[  66.6800723] --- syscall (number 202) ---
[  66.6800723] netbsd:syscall+0x98:
[  66.6800723] cpu0: End traceback...

[  66.6800723] dumping to dev 142,1 (offset=0, size=0): not possible
[  66.6800723] rebooting...

>How-To-Repeat:
On the host, with a domU called test20260715:

# xl save -p -D test20260715 test20260715.xenckpt

In the guest, probably:

# drvctl -S xbd0
>Fix:
	if (sc->sc_features & BLKIF_FEATURE_INDIRECT) ...