syzbot

uvm_fault(fffffd805f2f3030,368fb563000,0,1) at uvm_fault+0x106 sys/uvm/uvm_fault.c:677
upageflttrap(ffff80003c4ef7d0,368fb563330) at upageflttrap+0xa9 sys/arch/amd64/amd64/trap.c:188
usertrap(ffff80003c4ef7d0) at usertrap+0x2d8 sys/arch/amd64/amd64/trap.c:436
recall_trap() at recall_trap+0x8
end of kernel
end trace frame: 0x7605d095e880, count: -13
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(fffffd806e155898,9,0) at witness_checkorder+0x10fb sys/kern/subr_witness.c:-1
rw_do_enter_write(fffffd806e155880,1) at rw_do_enter_write+0xb7 sys/kern/kern_rwlock.c:232
rrw_enter(fffffd806e155880,1) at rrw_enter+0xc6 sys/kern/kern_rwlock.c:605
VOP_LOCK(fffffd806e156558,2001) at VOP_LOCK+0xa6 sys/kern/vfs_vops.c:527
vn_lock(fffffd806e156558,2001) at vn_lock+0xa4 sys/kern/vfs_vnops.c:570
vn_closefile(fffffd8062b5bda0,ffff80002a2962b0) at vn_closefile+0x111 vn_close sys/kern/vfs_vnops.c:292 [inline]
vn_closefile(fffffd8062b5bda0,ffff80002a2962b0) at vn_closefile+0x111 sys/kern/vfs_vnops.c:615
fdrop(fffffd8062b5bda0,ffff80002a2962b0) at fdrop+0x126 sys/kern/kern_descrip.c:1267
knote_remove(ffff80002a2962b0,fffffd8079716a80,fffffd8079716b10,3,0) at knote_remove+0x403 sys/kern/kern_event.c:2168
knote_fdclose(ffff80002a2962b0,3) at knote_fdclose+0xf9 sys/kern/kern_event.c:2203
fdrelease(ffff80002a2962b0,3) at fdrelease+0xf9 sys/kern/kern_descrip.c:750
syscall(ffff8000333f5c20) at syscall+0xbc6 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff8000333f5c20) at syscall+0xbc6 sys/arch/amd64/amd64/trap.c:579
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x543555e9010, count: -13