syzbot

uvm_fault(fffffd806bfbd9a0,77333301000,0,1) at uvm_fault+0x1ea sys/uvm/uvm_fault.c:650
upageflttrap(ffff80003c44d490,77333301000) at upageflttrap+0xa9 sys/arch/amd64/amd64/trap.c:192
usertrap(ffff80003c44d490) at usertrap+0x42f sys/arch/amd64/amd64/trap.c:632
recall_trap() at recall_trap+0x8
end of kernel
end trace frame: 0x76662316d290, count: -11
ddb{0}> machine ddbcpu 1
Stopped at      db_enter+0x25:  addq    $0x8,%rsp
ddb{1}> trace
db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438
witness_checkorder(fffffd806e854908,9,0) at witness_checkorder+0x10d1 sys/kern/subr_witness.c:-1
rw_do_enter_write(fffffd806e8548f0,1) at rw_do_enter_write+0xba sys/kern/kern_rwlock.c:234
rrw_enter(fffffd806e8548f0,1) at rrw_enter+0xc6 sys/kern/kern_rwlock.c:621
VOP_LOCK(fffffd806e857558,2001) at VOP_LOCK+0xbd sys/kern/vfs_vops.c:527
vn_lock(fffffd806e857558,2001) at vn_lock+0xa4 sys/kern/vfs_vnops.c:570
vn_closefile(fffffd805d9bac60,ffff8000fffef240) at vn_closefile+0x111 vn_close sys/kern/vfs_vnops.c:292 [inline]
vn_closefile(fffffd805d9bac60,ffff8000fffef240) at vn_closefile+0x111 sys/kern/vfs_vnops.c:615
fdrop(fffffd805d9bac60,ffff8000fffef240) at fdrop+0x121 sys/kern/kern_descrip.c:1280
knote_drop(fffffd805fcad448,ffff8000fffef240) at knote_drop+0x1a1 sys/kern/kern_event.c:2296
knote_remove(ffff8000fffef240,fffffd806f55ab60,fffffd806f55abf0,3,0) at knote_remove+0x215 sys/kern/kern_event.c:-1
knote_fdclose(ffff8000fffef240,3) at knote_fdclose+0xf9 sys/kern/kern_event.c:2203
fdrelease(ffff8000fffef240,3) at fdrelease+0xf9 sys/kern/kern_descrip.c:760
syscall(ffff80003c484fb0) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80003c484fb0) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:775
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x844eb64d720, count: -14