r286256 (changes in both schedulers) leads to almost-instant reboot on my system.

Hello freebsd-current,

   I've tracked down my reboot on r289874 to r286256. My system crashes
 after several  seconds of running with several post-286256 revisions
 (r289874 is tested  most by me). But if I revert r286256 (and only this
 one), r289874 works  solid-stable with both ULE and 4BSD. It is amd64
 system.

  Typical panic logs look like this:

======================================================================
gif0: link state changed to UP
kernel trap 9 with interrupts disabled


Fatal trap 9: general protection fault while in kernel mode
cpuid = 0; apic id = 00
instruction pointer     = 0x20:0xffffffff8046e3c6
stack pointer           = 0x28:0xfffffe011bd59890
frame pointer           = 0x28:0xfffffe011bd59980
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags        = resume, IOPL = 0
current process         = 11 (swi4: clock (0))
trap number             = 9
panic: general protection fault
cpuid = 0
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe011bd59530
vpanic() at vpanic+0x182/frame 0xfffffe011bd595b0
panic() at panic+0x43/frame 0xfffffe011bd59610
trap_fatal() at trap_fatal+0x351/frame 0xfffffe011bd59670
trap() at trap+0x6d8/frame 0xfffffe011bd597d0
calltrap() at calltrap+0x8/frame 0xfffffe011bd597d0
--- trap 0x9, rip = 0xffffffff8046e3c6, rsp = 0xfffffe011bd598a0, rbp = 0xfffffe011bd59980 ---
sched_add() at sched_add+0x116/frame 0xfffffe011bd59980
intr_event_schedule_thread() at intr_event_schedule_thread+0xae/frame 0xfffffe011bd599b0
intr_event_handle() at intr_event_handle+0xe2/frame 0xfffffe011bd59a00
intr_execute_handlers() at intr_execute_handlers+0x48/frame 0xfffffe011bd59a30
lapic_handle_intr() at lapic_handle_intr+0x3f/frame 0xfffffe011bd59a50
Xapic_isr1() at Xapic_isr1+0xb7/frame 0xfffffe011bd59a50
--- interrupt, rip = 0xffffffff8063e1f2, rsp = 0xfffffe011bd59b20, rbp = 0xfffffe011bd59b20 ---
spinlock_exit() at spinlock_exit+0x32/frame 0xfffffe011bd59b20
intr_event_execute_handlers() at intr_event_execute_handlers+0xae/frame 0xfffffe011bd59b60
ithread_loop() at ithread_loop+0xa6/frame 0xfffffe011bd59bb0
fork_exit() at fork_exit+0x75/frame 0xfffffe011bd59bf0
fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe011bd59bf0
--- trap 0, rip = 0, rsp = 0, rbp = 0 ---
Uptime: 16s
======================================================================
wlan0: AP-ENABLED
kernel trap 9 with interrupts disabled


Fatal trap 9: general protection fault while in kernel mode
cpuid = 0; apic id = 00
instruction pointer     = 0x20:0xffffffff805190b6
stack pointer           = 0x28:0xfffffe012260e7d0
frame pointer           = 0x28:0xfffffe012260e8c0
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags        = resume, IOPL = 0
current process         = 16 (syncer)
trap number             = 9
panic: general protection fault
cpuid = 0
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe012260e470
vpanic() at vpanic+0x182/frame 0xfffffe012260e4f0
panic() at panic+0x43/frame 0xfffffe012260e550
trap_fatal() at trap_fatal+0x351/frame 0xfffffe012260e5b0
trap() at trap+0x6d8/frame 0xfffffe012260e710
calltrap() at calltrap+0x8/frame 0xfffffe012260e710
--- trap 0x9, rip = 0xffffffff805190b6, rsp = 0xfffffe012260e7e0, rbp = 0xfffffe012260e8c0 ---
sched_add() at sched_add+0x116/frame 0xfffffe012260e8c0
intr_event_schedule_thread() at intr_event_schedule_thread+0xae/frame 0xfffffe012260e8f0
intr_event_handle() at intr_event_handle+0xe2/frame 0xfffffe012260e940
intr_execute_handlers() at intr_execute_handlers+0x48/frame 0xfffffe012260e970
lapic_handle_intr() at lapic_handle_intr+0x3f/frame 0xfffffe012260e990
Xapic_isr1() at Xapic_isr1+0xb7/frame 0xfffffe012260e990
--- interrupt, rip = 0xffffffff8071eaad, rsp = 0xfffffe012260ea60, rbp = 0xfffffe012260ea70 ---
spinlock_exit() at spinlock_exit+0x2d/frame 0xfffffe012260ea70
sleepq_timedwait() at sleepq_timedwait+0xd3/frame 0xfffffe012260eaa0
_cv_timedwait_sbt() at _cv_timedwait_sbt+0x1a0/frame 0xfffffe012260eb10
sched_sync() at sched_sync+0x6b6/frame 0xfffffe012260ebb0
fork_exit() at fork_exit+0x75/frame 0xfffffe012260ebf0
fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe012260ebf0
--- trap 0, rip = 0, rsp = 0, rbp = 0 ---
Uptime: 14s
======================================================================


-- 
Best regards,
 Lev                          mailto:lev_at_FreeBSD.org