*cpu0: uvm_fault(0xfffffd806c21f1f8, 0x1960, 0, 2) -> e ddb{1}> trace savectx() at savectx+0xae end of kernel end trace frame: 0x791b47272ff0, count: -1 ddb{1}> show registers rdi 0 rsi 0 rbp 0xffff80002a293290 rbx 0 rdx 0 rcx 0xffff80002a2ba7c8 rax 0x31 r8 0xffff80002a2931c0 r9 0xffff80002a292e88 r10 0xd213ec24b3fa836d r11 0x15b44b86eef099b0 r12 0 r13 0 r14 0xffff80002a2ba7c8 r15 0 rip 0xffffffff831e13ee savectx+0xae cs 0x8 rflags 0x46 rsp 0xffff80002a293210 ss 0x10 savectx+0xae: movl $0,%gs:0x688 ddb{1}> show proc PROC (syz-executor) tid=217765 pid=10571 tcnt=1 stat=onproc flags process=2 proc=0 runpri=24, usrpri=52, slppri=24, nice=20 wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0 forw=0xffffffffffffffff, list=0xffff80002a2baf78,0xffff80002a2ba028 process=0xffff80002a275370 user=0xffff80002a28e000, vmspace=0xfffffd806e394790 estcpu=2, cpticks=8, pctcpu=0.31, user=2, sys=39, intr=1 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 28511 483070 15839 0 2 0 syz-executor 28511 159386 15839 0 7 0x4000000 syz-executor 28511 443751 15839 0 3 0x4000080 fsleep syz-executor 28511 501827 15839 0 3 0x4000080 fsleep syz-executor 74900 268775 20933 0 2 0 syz-executor 29963 270240 27533 0 2 0 syz-executor 29963 286700 27533 0 2 0x4000000 syz-executor 98276 461566 50321 0 2 0 syz-executor 98276 82748 50321 0 2 0x4000000 syz-executor 98276 439627 50321 0 2 0x4000000 syz-executor 31778 61260 14296 0 2 0 syz-executor 18757 412503 36176 0 2 0 syz-executor 18757 512999 36176 0 3 0x4000080 fsleep syz-executor 18757 429195 36176 0 3 0x4000080 fsleep syz-executor 69307 464474 41466 0 2 0 syz-executor 69307 274866 41466 0 3 0x4000080 tunread syz-executor 69307 254140 41466 0 2 0x4000000 syz-executor 69307 318276 41466 0 2 0x4000000 syz-executor 75694 389355 45600 60929 2 0x10 syz-executor 75694 477201 45600 60929 3 0x4000090 ttyout syz-executor 75694 78177 45600 60929 2 0x4000010 syz-executor 75694 451222 45600 60929 3 0x4000090 fsleep syz-executor 69102 294974 0 0 3 0x14200 bored sosplice 36176 104125 10571 0 2 0xc82 syz-executor 14296 268122 10571 0 2 0xc82 syz-executor 50321 84893 10571 0 2 0xc82 syz-executor 15839 77480 10571 0 2 0xc82 syz-executor 45600 416238 10571 0 2 0x2 syz-executor 41466 34682 10571 0 2 0xc82 syz-executor 20933 449809 10571 0 2 0xc82 syz-executor 27533 114808 10571 0 2 0xc82 syz-executor *10571 217765 28415 0 7 0x2 syz-executor 28415 478487 51509 0 3 0x10008a sigsusp ksh 51509 207336 44316 0 3 0x98 kqread sshd-session 44316 506801 95782 0 3 0x92 kqread sshd-session 41865 45336 1 0 3 0x100083 ttyin getty 95782 433132 1 0 3 0x88 kqread sshd 10222 150304 50190 74 3 0x1100092 bpf pflogd 50190 243576 1 0 3 0x80 sbwait pflogd 73627 57698 16873 73 3 0x1100090 kqread syslogd 16873 384632 1 0 3 0x100082 sbwait syslogd 7776 95395 1 0 3 0x100080 kqread resolvd 68721 401597 48578 77 3 0x100092 kqread dhcpleased 27800 383802 48578 77 3 0x100092 kqread dhcpleased 48578 255892 1 0 3 0x80 kqread dhcpleased 75477 422194 0 0 3 0x14200 bored smr 67232 394517 0 0 2 0x14200 zerothread 63954 344874 0 0 3 0x14200 aiodoned aiodoned 57597 306363 0 0 3 0x14200 syncer update 81631 165650 0 0 3 0x14200 cleaner cleaner 76760 64372 0 0 3 0x14200 reaper reaper 36459 325701 0 0 3 0x14200 pgdaemon pagedaemon 88213 249669 0 0 3 0x14200 bored viomb 12704 373652 0 0 3 0x40014200 acpi0 acpi0 84334 299713 0 0 3 0x40014200 idle1 57170 44309 0 0 3 0x14200 bored softnet3 6964 52541 0 0 3 0x14200 bored softnet2 37768 387574 0 0 3 0x14200 bored softnet1 49722 448030 0 0 2 0x14200 softnet0 88622 517364 0 0 3 0x14200 bored systqmp 30438 435186 0 0 3 0x14200 bored systq 42225 143617 0 0 3 0x14200 tmoslp softclockmp 14060 490789 0 0 2 0x40014200 softclock 54178 113417 0 0 3 0x40014200 idle0 1 511027 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks CPU 1: exclusive mutex /syzkaller/managers/multicore/kernel/sys/kern/kern_malloc.c:96 r = 0 (0xffffffff83857a38) #0 witness_lock+0x5bb stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5bb sys/kern/subr_witness.c:1160 #1 mtx_enter_try+0x1ad sys/kern/kern_lock.c:296 #2 mtx_enter+0x62 sys/kern/kern_lock.c:253 #3 malloc+0x2f9 sys/kern/kern_malloc.c:199 #4 ktrsyscall+0x17c sys/kern/kern_ktrace.c:174 #5 syscall+0x2e6 mi_syscall sys/sys/syscall_mi.h:154 [inline] #5 syscall+0x2e6 sys/arch/amd64/amd64/trap.c:579 #6 Xsyscall+0x128 ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 10227 11383K 11383K 166960K 11393 0 pcb 20 12K 12K 166960K 31 0 rtable 236 6K 6K 166960K 352 0 pf 37 18K 20K 166960K 53 0 ifaddr 44 7K 7K 166960K 48 0 ifgroup 60 2K 2K 166960K 64 0 sysctl 1 1K 9K 166960K 7 0 counters 70 37K 37K 166960K 74 0 ioctlops 0 0K 4K 166960K 1490 0 iov 0 0K 12K 166960K 3 0 mount 1 1K 1K 166960K 1 0 log 0 0K 0K 166960K 4 0 vnodes 1356 85K 85K 166960K 1419 0 UFS quota 1 32K 32K 166960K 1 0 UFS mount 5 36K 36K 166960K 5 0 shm 2 1K 5K 166960K 4 0 VM map 2 1K 1K 166960K 2 0 sem 6 0K 0K 166960K 6 0 dirhash 12 2K 2K 166960K 15 0 ACPI 1692 195K 286K 166960K 12470 0 file desc 18 65K 89K 166960K 207 0 sigio 0 0K 0K 166960K 2 0 proc 72 91K 115K 166960K 538 0 subproc 72 4K 4K 166960K 72 0 NFS srvsock 1 0K 0K 166960K 1 0 NFS daemon 1 16K 16K 166960K 1 0 ip_moptions 0 0K 0K 166960K 6 0 in_multi 99 7K 7K 166960K 101 0 ether_multi 1 0K 0K 166960K 1 0 ISOFS mount 1 32K 32K 166960K 1 0 MSDOSFS mount 1 16K 16K 166960K 1 0 ttys 37 175K 175K 166960K 37 0 exec 0 0K 1K 166960K 369 0 fusefs mount 1 32K 32K 166960K 1 0 pfkey data 0 0K 0K 166960K 1 0 tdb 3 0K 0K 166960K 3 0 VM swap 8 62K 64K 166960K 10 0 UVM amap 240 168K 177K 166960K 3569 0 UVM aobj 4 2K 2K 166960K 5 0 pinsyscall 43 86K 101K 166960K 1285 0 memdesc 1 4K 4K 166960K 1 0 crypto data 1 1K 1K 166960K 1 0 ip6_options 0 0K 0K 166960K 4 0 NDP 13 0K 2K 166960K 31 0 temp 35 8686K 8750K 166960K 8678 0 kqueue 13 20K 22K 166960K 26 0 SYN cache 2 16K 16K 166960K 2 0 ddb{1}> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle plcache 128 26 0 0 1 0 1 1 0 8 0 rtpcb 120 40 0 36 1 0 1 1 0 8 0 rtentry 176 112 0 1 6 0 6 6 0 8 0 unpcb 144 73 0 55 1 0 1 1 0 8 0 syncache 336 3 0 3 1 0 1 1 0 8 1 tcpcb 808 57 0 53 4 0 4 4 0 8 3 arp 128 18 0 0 1 0 1 1 0 8 0 inpcb 328 136 0 128 4 0 4 4 0 8 3 nd6 144 25 0 0 1 0 1 1 0 8 0 pkpcb 40 1 0 0 1 0 1 1 0 8 0 kcovpl 48 8 0 0 1 0 1 1 0 8 0 ppxss 1192 2 0 2 1 0 1 1 0 8 1 pfosfp 40 1428 0 1005 5 0 5 5 0 8 0 pfosfpen 112 1428 0 714 21 0 21 21 0 8 0 pfstitem 24 18 0 0 1 0 1 1 0 8 0 pfstkey 128 18 0 0 1 0 1 1 0 8 0 pfstate 384 18 0 0 2 0 2 2 0 8 0 pfrule 1344 21 0 16 2 1 1 2 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 467 0 0 30 0 30 30 0 8 0 art_table 32 468 0 0 4 0 4 4 0 8 0 art_node 16 111 0 10 1 0 1 1 0 8 0 sysvmsgpl 40 2 0 1 1 0 1 1 0 8 0 semapl 112 4 0 0 1 0 1 1 0 8 0 shmpl 112 2 0 1 1 0 1 1 0 8 0 dirhash 1024 19 0 2 3 0 3 3 0 8 0 dino2pl 256 1666 0 152 95 0 95 95 0 8 0 ffsino 288 1666 0 152 109 0 109 109 0 8 0 nchpl 144 1959 0 267 63 0 63 63 0 8 0 uvmvnodes 80 1797 0 0 37 0 37 37 0 8 0 vnodes 216 1797 0 0 100 0 100 100 0 8 0 namei 1024 5970 0 5970 2 0 2 2 0 8 2 percpumem 16 52 0 2 1 0 1 1 0 8 0 kstatmem 264 32 0 4 2 0 2 2 0 8 0 scxspl 216 6547 0 6547 9 1 8 8 1 8 8 plimitpl 152 30 0 13 1 0 1 1 0 8 0 sigapl 424 506 0 455 7 0 7 7 0 8 1 knotepl 120 233 0 0 8 0 8 8 0 8 0 kqueuepl 224 28 0 17 1 0 1 1 0 8 0 pipepl 336 109 0 82 3 0 3 3 0 8 0 fdescpl 520 487 0 455 3 0 3 3 0 8 0 filepl 160 1797 0 1572 12 1 11 11 0 8 1 lockfpl 104 27 0 25 1 0 1 1 0 8 0 lockfspl 48 12 0 10 1 0 1 1 0 8 0 sessionpl 144 22 0 13 1 0 1 1 0 8 0 pgrppl 48 30 0 13 1 0 1 1 0 8 0 ucredpl 104 96 0 82 1 0 1 1 0 8 0 zombiepl 144 455 0 455 1 0 1 1 0 8 1 processpl 1240 506 0 455 5 0 5 5 0 8 0 procpl 656 624 0 559 6 0 6 6 0 8 0 sockpl 728 253 0 218 6 0 6 6 0 8 2 mcl64k 65536 1 0 0 1 0 1 1 0 8 0 mcl8k 8192 2 0 0 1 0 1 1 0 8 0 mcl4k 4096 112 0 0 14 0 14 14 0 8 0 mcl2k2 2112 1 0 0 1 0 1 1 0 8 0 mcl2k 2048 24 0 0 3 0 3 3 0 8 0 mtagpl 96 4 0 0 1 0 1 1 0 8 0 mbufpl 256 188 0 0 12 0 12 12 0 8 0 bufpl 280 2404 0 118 164 0 164 164 0 8 0 anonpl 32 6137 0 0 50 0 50 50 0 246 0 amapchunkpl 152 10575 0 10027 25 0 25 25 0 158 3 amappl16 200 2050 0 2007 5 1 4 5 0 8 0 amappl15 192 3 0 3 1 1 0 1 0 8 0 amappl14 184 109 0 96 1 0 1 1 0 8 0 amappl13 176 4 0 3 1 0 1 1 0 8 0 amappl12 168 1124 0 1094 4 1 3 3 0 8 0 amappl11 160 52 0 38 1 0 1 1 0 8 0 amappl10 152 11 0 11 1 1 0 1 0 8 0 amappl9 144 262 0 262 1 1 0 1 0 8 0 amappl8 136 23 0 20 1 0 1 1 0 8 0 amappl7 128 108 0 96 1 0 1 1 0 8 0 amappl6 120 183 0 178 1 0 1 1 0 8 0 amappl5 112 136 0 127 1 0 1 1 0 8 0 amappl4 104 307 0 288 1 0 1 1 0 8 0 amappl3 96 1705 0 1596 5 1 4 4 0 8 0 amappl2 88 628 0 565 2 0 2 2 0 8 0 amappl1 80 8460 0 7860 15 1 14 15 0 8 1 amappl 88 2893 0 2727 5 0 5 5 0 92 0 dma4096 4096 1 0 1 1 1 0 1 0 8 0 dma1024 1024 1 0 0 1 0 1 1 0 8 0 dma256 256 6 0 6 1 1 0 1 0 8 0 dma128 128 253 0 253 1 1 0 1 0 8 0 dma64 64 6 0 6 1 1 0 1 0 8 0 dma32 32 7 0 7 1 1 0 1 0 8 0 dma16 16 18 0 17 1 0 1 1 0 8 0 aobjpl 72 4 0 1 1 0 1 1 0 8 0 uaddrrnd 24 487 0 455 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 487 0 455 1 0 1 1 0 8 0 vmmpekpl 168 5571 0 5535 3 0 3 3 0 8 0 vmmpepl 168 37419 0 35396 90 0 90 90 0 357 1 vmsppl 480 486 0 455 5 0 5 5 0 8 1 rwobjpl 72 14969 0 12229 50 0 50 50 0 8 0 pdppl 4096 981 0 910 95 24 71 83 0 8 0 pvpl 32 13670 0 0 111 0 111 111 0 265 0 pmappl 256 486 0 455 3 0 3 3 0 8 0 extentpl 40 45 0 27 1 0 1 1 0 8 0 phpool 112 380 0 26 11 0 11 11 0 8 0 ddb{1}> machine ddbcpu 0 Stopped at x86_ipi_db+0x27: addq $0x8,%rsp x86_ipi_db(ffffffff8382eff0) at x86_ipi_db+0x27 sys/arch/amd64/amd64/db_interface.c:394 x86_ipi_handler() at x86_ipi_handler+0xd9 sys/arch/amd64/amd64/ipi.c:106 Xresume_lapic_ipi() at Xresume_lapic_ipi+0x27 x86_bus_space_io_read_4(b008,0) at x86_bus_space_io_read_4+0x37 sys/arch/amd64/amd64/bus_space.c:666 acpitimer_delay(1) at acpitimer_delay+0x58 acpitimer_read sys/dev/acpi/acpitimer.c:141 [inline] acpitimer_delay(1) at acpitimer_delay+0x58 sys/dev/acpi/acpitimer.c:120 comcnputc(800,3e) at comcnputc+0x29b sys/dev/ic/com.c:1269 cnputc(3e) at cnputc+0x61 sys/dev/cons.c:218 db_putchar(3e) at db_putchar+0x65c sys/ddb/db_output.c:155 kprintf() at kprintf+0x2aba sys/kern/subr_prf.c:1065 db_printf(ffffffff8340a9a7) at db_printf+0x9b sys/kern/subr_prf.c:-1 fault(ffffffff833ab785) at fault+0xa7 sys/arch/amd64/amd64/trap.c:157 kpageflttrap(ffff80003c4719f0,1960) at kpageflttrap+0x385 sys/arch/amd64/amd64/trap.c:290 kerntrap(ffff80003c4719f0) at kerntrap+0x14a sys/arch/amd64/amd64/trap.c:332 alltraps_kern_meltdown() at alltraps_kern_meltdown+0x7b end trace frame: 0xffff80003c471d60, count: 0 ddb{0}> trace x86_ipi_db(ffffffff8382eff0) at x86_ipi_db+0x27 sys/arch/amd64/amd64/db_interface.c:394 x86_ipi_handler() at x86_ipi_handler+0xd9 sys/arch/amd64/amd64/ipi.c:106 Xresume_lapic_ipi() at Xresume_lapic_ipi+0x27 x86_bus_space_io_read_4(b008,0) at x86_bus_space_io_read_4+0x37 sys/arch/amd64/amd64/bus_space.c:666 acpitimer_delay(1) at acpitimer_delay+0x58 acpitimer_read sys/dev/acpi/acpitimer.c:141 [inline] acpitimer_delay(1) at acpitimer_delay+0x58 sys/dev/acpi/acpitimer.c:120 comcnputc(800,3e) at comcnputc+0x29b sys/dev/ic/com.c:1269 cnputc(3e) at cnputc+0x61 sys/dev/cons.c:218 db_putchar(3e) at db_putchar+0x65c sys/ddb/db_output.c:155 kprintf() at kprintf+0x2aba sys/kern/subr_prf.c:1065 db_printf(ffffffff8340a9a7) at db_printf+0x9b sys/kern/subr_prf.c:-1 fault(ffffffff833ab785) at fault+0xa7 sys/arch/amd64/amd64/trap.c:157 kpageflttrap(ffff80003c4719f0,1960) at kpageflttrap+0x385 sys/arch/amd64/amd64/trap.c:290 kerntrap(ffff80003c4719f0) at kerntrap+0x14a sys/arch/amd64/amd64/trap.c:332 alltraps_kern_meltdown() at alltraps_kern_meltdown+0x7b copyout() at copyout+0x57 syscall(ffff80003c471e40) at syscall+0xbc6 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80003c471e40) at syscall+0xbc6 sys/arch/amd64/amd64/trap.c:579 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xb3b4bd4aca0, count: -17 ddb{0}> machine ddbcpu 1 Stopped at savectx+0xae: movl $0,%gs:0x688 savectx() at savectx+0xae end of kernel end trace frame: 0x791b47272ff0, count: 14 ddb{1}> trace savectx() at savectx+0xae end of kernel end trace frame: 0x791b47272ff0, count: -1