syzbot

uvm_fault(fffffd805439c8a8,1f3000,0,2) at uvm_fault+0x112 sys/uvm/uvm_fault.c:600
kpageflttrap(ffff80002a0cdf80,1f3a60) at kpageflttrap+0x2d0 sys/arch/amd64/amd64/trap.c:279
kerntrap(ffff80002a0cdf80) at kerntrap+0x14a sys/arch/amd64/amd64/trap.c:332
alltraps_kern_meltdown() at alltraps_kern_meltdown+0x7b
copyout() at copyout+0x57
syscall(ffff80002a0ce3d0) at syscall+0xbb6 mi_syscall sys/sys/syscall_mi.h:179 [inline]
syscall(ffff80002a0ce3d0) at syscall+0xbb6 sys/arch/amd64/amd64/trap.c:577
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x3c210ffb540, count: -21
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:437
witness_checkorder(fffffd806de69d58,9,0) at witness_checkorder+0x1024
rw_enter(fffffd806de69d48,1) at rw_enter+0x122
rrw_enter(fffffd806de69d48,1) at rrw_enter+0xbe sys/kern/kern_rwlock.c:464
VOP_LOCK(fffffd8068940a50,2001) at VOP_LOCK+0xa6 sys/kern/vfs_vops.c:524
vn_lock(fffffd8068940a50,2001) at vn_lock+0xa4 sys/kern/vfs_vnops.c:564
vfs_getcwd_common(fffffd8068940a50,fffffd8068940a50,0,0,200,0,ab9298b7bd059309) at vfs_getcwd_common+0xd1 sys/kern/vfs_getcwd.c:287
vn_isunder(fffffd8068940a50,fffffd8068940a50,ffff800032982300) at vn_isunder+0x56 sys/kern/vfs_vnops.c:688
unp_externalize(fffffd8061537300,ec,0) at unp_externalize+0x286 sys/kern/uipc_usrreq.c:1088
soreceive(ffff8000012622e8,ffff80002a09fd58,ffff80002a09fd08,0,ffff80002a09fd48,ffff80002a09fecc,5991084d983db7c1) at soreceive+0xd3e sys/kern/uipc_socket.c:1091
recvit(ffff800032982300,5,ffff80002a09fea0,0,ffff80002a09ff50) at recvit+0x40a sys/kern/uipc_syscalls.c:1082
sys_recvmsg(ffff800032982300,ffff80002a0a0000,ffff80002a09ff50) at sys_recvmsg+0x1bf sys/kern/uipc_syscalls.c:882
syscall(ffff80002a0a0000) at syscall+0xbb6 mi_syscall sys/sys/syscall_mi.h:179 [inline]
syscall(ffff80002a0a0000) at syscall+0xbb6 sys/arch/amd64/amd64/trap.c:577
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x482231b47e0, count: -14