DragonFly/x86_64 (dfbsd) (ttyd0) login: DF-2532: constructing impossible state DF-2532: calling xa_start(tag, NULL, 1) with empty spanq, B_FAILONDIS set, tag->bio=0xfffff8004f1e8640 DF-2532: xa_start will find no spans (trans=NULL) -> goto skip DF-2532: B_FAILONDIS set -> else branch -> xa_done(tag,1) DF-2532: xa_done KKASSERT(tag->bio==NULL) should PANIC now panic: assertion "tag->bio == NULL" failed in xa_done at xdisk.c:1009 cpuid = 0 Trace beginning at frame 0xfffff8011847d6c8 xa_done() at xa_done+0x9c 0xffffffff82600b1c xa_done() at xa_done+0x9c 0xffffffff82600b1c xa_start() at xa_start+0x268 0xffffffff826007f8 df2532_trigger() at df2532_trigger+0x335 0xffffffff82600ff5 sysctl_root.isra.5() at sysctl_root.isra.5+0x166 0xffffffff80683d06 userland_sysctl() at userland_sysctl+0x111 0xffffffff806840a1 Debugger("panic") CPU0 stopping CPUs: 0x0000003e stopped Stopped at Debugger+0x7c: movb $0,0xbdaf09(%rip) db>