panic: acquiring blockable sleep lock with spinlock or critical section held (kernel_lock) &kernel_lock Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 382609 52650 0 0 0 1 syz-executor.0 *479930 67760 0 0 0x4000000 0 syz-executor.1 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic() at panic+0x15c sys/kern/subr_prf.c:207 witness_checkorder(ffffffff8265f5f8,9,0) at witness_checkorder+0x10cc sys/kern/subr_witness.c:820 __mp_lock(ffffffff8265f3f0) at __mp_lock+0xa1 pageflttrap() at pageflttrap+0x6f sys/arch/amd64/amd64/trap.c:162 kerntrap(ffff800023b9b220) at kerntrap+0xec sys/arch/amd64/amd64/trap.c:287 alltraps_kern_meltdown(6,0,600,0,fffffd806b35d054,fffffd80669e1e68) at alltraps_kern_meltdown+0x7b frag6_input(ffff800023b9b588,ffff800023b9b594,2c,18) at frag6_input+0x7d2 sys/netinet6/frag6.c:321 ip_deliver(ffff800023b9b588,ffff800023b9b594,2c,18) at ip_deliver+0x353 sys/netinet/ip_input.c:665 ip6_input_if(ffff800023b9b588,ffff800023b9b594,29,0,ffff80000066d000) at ip6_input_if+0x17d4 ip6_ours sys/netinet6/ip6_input.c:518 [inline] ip6_input_if(ffff800023b9b588,ffff800023b9b594,29,0,ffff80000066d000) at ip6_input_if+0x17d4 sys/netinet6/ip6_input.c:340 ipv6_input(ffff80000066d000,fffffd806985a300) at ipv6_input+0x48 sys/netinet6/ip6_input.c:171 if_input_local(ffff80000066d000,fffffd806985a300,18) at if_input_local+0x121 sys/net/if.c:783 ip6_output(fffffd806492e100,ffff800000a9bc00,fffffd806f6bbb60,0,0,fffffd806f6bbaf0) at ip6_output+0xd59 rip6_output(fffffd806492e100,fffffd8066b537a0,ffff800023b9b8f8,0) at rip6_output+0x4c0 sys/netinet6/raw_ip6.c:481 end trace frame: 0xffff800023b9b990, count: 0 https://www.openbsd.org/ddb.html describes the minimum info required in bug reports. Insufficient info makes it difficult to find and fix bugs. ddb{0}> ddb{0}> set $lines = 0 ddb{0}> set $maxwidth = 0 ddb{0}> show panic acquiring blockable sleep lock with spinlock or critical section held (kernel_lock) &kernel_lock ddb{0}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic() at panic+0x15c sys/kern/subr_prf.c:207 witness_checkorder(ffffffff8265f5f8,9,0) at witness_checkorder+0x10cc sys/kern/subr_witness.c:820 __mp_lock(ffffffff8265f3f0) at __mp_lock+0xa1 pageflttrap() at pageflttrap+0x6f sys/arch/amd64/amd64/trap.c:162 kerntrap(ffff800023b9b220) at kerntrap+0xec sys/arch/amd64/amd64/trap.c:287 alltraps_kern_meltdown(6,0,600,0,fffffd806b35d054,fffffd80669e1e68) at alltraps_kern_meltdown+0x7b frag6_input(ffff800023b9b588,ffff800023b9b594,2c,18) at frag6_input+0x7d2 sys/netinet6/frag6.c:321 ip_deliver(ffff800023b9b588,ffff800023b9b594,2c,18) at ip_deliver+0x353 sys/netinet/ip_input.c:665 ip6_input_if(ffff800023b9b588,ffff800023b9b594,29,0,ffff80000066d000) at ip6_input_if+0x17d4 ip6_ours sys/netinet6/ip6_input.c:518 [inline] ip6_input_if(ffff800023b9b588,ffff800023b9b594,29,0,ffff80000066d000) at ip6_input_if+0x17d4 sys/netinet6/ip6_input.c:340 ipv6_input(ffff80000066d000,fffffd806985a300) at ipv6_input+0x48 sys/netinet6/ip6_input.c:171 if_input_local(ffff80000066d000,fffffd806985a300,18) at if_input_local+0x121 sys/net/if.c:783 ip6_output(fffffd806492e100,ffff800000a9bc00,fffffd806f6bbb60,0,0,fffffd806f6bbaf0) at ip6_output+0xd59 rip6_output(fffffd806492e100,fffffd8066b537a0,ffff800023b9b8f8,0) at rip6_output+0x4c0 sys/netinet6/raw_ip6.c:481 rip6_usrreq(fffffd8066b537a0,9,fffffd806492e100,0,0,ffff800020a5ec60) at rip6_usrreq+0x5cd sys/netinet6/raw_ip6.c:670 sosend(fffffd8066b537a0,0,ffff800023b9bb28,0,0,0) at sosend+0x668 sys/kern/uipc_socket.c:524 dofilewritev(ffff800020a5ec60,3,ffff800023b9bb28,0,ffff800023b9bc30) at dofilewritev+0x1ac sys/kern/sys_generic.c:364 sys_write(ffff800020a5ec60,ffff800023b9bbc8,ffff800023b9bc30) at sys_write+0x83 sys/kern/sys_generic.c:284 syscall(ffff800023b9bca0) at syscall+0x552 mi_syscall sys/sys/syscall_mi.h:92 [inline] syscall(ffff800023b9bca0) at syscall+0x552 sys/arch/amd64/amd64/trap.c:555 Xsyscall(6,0,c,0,3,d3367a32010) at Xsyscall+0x128 end of kernel end trace frame: 0xd35c73889f0, count: -20 ddb{0}> show registers rdi 0xffffffff81d56a37 db_enter+0x17 rsi 0x2f40 __ALIGN_SIZE+0x1f40 rbp 0xffff800023b9af80 rbx 0xffff800023b9b030 rdx 0x2f41 __ALIGN_SIZE+0x1f41 rcx 0xffff800021b7a000 rax 0xffff800021b7a000 r8 0xffffffff812e94e3 kprintf+0x173 r9 0x1 r10 0x25 r11 0xafc1b11f2afa7ce0 r12 0x3000000008 r13 0xffff800023b9af90 r14 0x100 r15 0x1 rip 0xffffffff81d56a38 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800023b9af70 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor.1) pid=479930 stat=onproc flags process=0 proc=4000000 pri=86, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff800020a5fb30,0xffff800020abf3e8 process=0xffff800020adc000 user=0xffff800023b96000, vmspace=0xfffffd807f00bb80 estcpu=36, cpticks=2, pctcpu=0.0 user=0, sys=1, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 52650 382609 32176 0 7 0 syz-executor.0 52650 294525 32176 0 2 0x4000000 syz-executor.0 67760 384551 31599 0 2 0 syz-executor.1 *67760 479930 31599 0 7 0x4000000 syz-executor.1 31599 483412 93080 0 3 0x82 nanosleep syz-executor.1 46355 423030 1 0 3 0x100083 ttyin getty 95727 152987 0 0 3 0x14200 bored sosplice 32176 48248 93080 0 3 0x82 nanosleep syz-executor.0 93080 499689 45613 0 3 0x82 thrsleep syz-fuzzer 93080 92206 45613 0 3 0x4000082 nanosleep syz-fuzzer 93080 302276 45613 0 3 0x4000082 thrsleep syz-fuzzer 93080 120372 45613 0 3 0x4000082 thrsleep syz-fuzzer 93080 458138 45613 0 3 0x4000082 thrsleep syz-fuzzer 93080 303052 45613 0 3 0x4000082 thrsleep syz-fuzzer 93080 467744 45613 0 3 0x4000082 kqread syz-fuzzer 93080 298289 45613 0 3 0x4000082 thrsleep syz-fuzzer 93080 80473 45613 0 3 0x4000082 nanosleep syz-fuzzer 93080 200961 45613 0 3 0x4000082 thrsleep syz-fuzzer 45613 327094 92536 0 3 0x10008a pause ksh 92536 419740 94502 0 3 0x92 select sshd 94502 181395 1 0 3 0x80 select sshd 23159 395012 37353 74 3 0x100092 bpf pflogd 37353 210496 1 0 3 0x80 netio pflogd 65057 44081 39524 73 3 0x100090 kqread syslogd 39524 154219 1 0 3 0x100082 netio syslogd 29478 464992 1 77 3 0x100090 poll dhclient 93050 91823 1 0 3 0x80 poll dhclient 94720 358979 0 0 2 0x14200 zerothread 48060 404057 0 0 3 0x14200 aiodoned aiodoned 12078 416901 0 0 3 0x14200 syncer update 9060 55114 0 0 3 0x14200 cleaner cleaner 94201 172880 0 0 3 0x14200 reaper reaper 40564 59902 0 0 3 0x14200 pgdaemon pagedaemon 3517 283220 0 0 3 0x14200 bored crynlk 8547 492758 0 0 3 0x14200 bored crypto 3783 15798 0 0 3 0x40014200 acpi0 acpi0 41950 517587 0 0 3 0x40014200 idle1 59984 135983 0 0 3 0x14200 bored softnet 81358 406141 0 0 3 0x14200 bored systqmp 77964 232062 0 0 3 0x14200 bored systq 74026 36468 0 0 3 0x40014200 bored softclock 5818 514175 0 0 3 0x40014200 idle0 65776 505177 0 0 3 0x14200 bored smr 1 107856 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks CPU 0: exclusive mutex /syzkaller/managers/multicore/kernel/sys/netinet6/frag6.c:57 r = 0 (0xffffffff824bae40) #0 witness_lock+0x52e sys/kern/subr_witness.c:1163 #1 mtx_enter_try+0x102 #2 mtx_enter+0x4b sys/kern/kern_lock.c:266 #3 frag6_input+0x237 sys/netinet6/frag6.c:183 #4 ip_deliver+0x353 sys/netinet/ip_input.c:665 #5 ip6_input_if+0x17d4 ip6_ours sys/netinet6/ip6_input.c:518 [inline] #5 ip6_input_if+0x17d4 sys/netinet6/ip6_input.c:340 #6 ipv6_input+0x48 sys/netinet6/ip6_input.c:171 #7 if_input_local+0x121 sys/net/if.c:783 #8 ip6_output+0xd59 #9 rip6_output+0x4c0 sys/netinet6/raw_ip6.c:481 #10 rip6_usrreq+0x5cd sys/netinet6/raw_ip6.c:670 #11 sosend+0x668 sys/kern/uipc_socket.c:524 #12 dofilewritev+0x1ac sys/kern/sys_generic.c:364 #13 sys_write+0x83 sys/kern/sys_generic.c:284 #14 syscall+0x552 mi_syscall sys/sys/syscall_mi.h:92 [inline] #14 syscall+0x552 sys/arch/amd64/amd64/trap.c:555 #15 Xsyscall+0x128 Process 52650 (syz-executor.0) thread 0xffff800020abf3d8 (382609) exclusive kernel_lock &kernel_lock r = 0 (0xffffffff8265f5f8) #0 witness_lock+0x52e sys/kern/subr_witness.c:1163 #1 pageflttrap+0x6f sys/arch/amd64/amd64/trap.c:162 #2 usertrap+0x249 sys/arch/amd64/amd64/trap.c:369 #3 recall_trap+0x8 Process 67760 (syz-executor.1) thread 0xffff800020a5ec60 (479930) exclusive rwlock netlock r = 0 (0xffffffff824c5488) #0 witness_lock+0x52e sys/kern/subr_witness.c:1163 #1 solock+0x5a sys/kern/uipc_socket2.c:282 #2 sosend+0x52c sys/kern/uipc_socket.c:512 #3 dofilewritev+0x1ac sys/kern/sys_generic.c:364 #4 sys_write+0x83 sys/kern/sys_generic.c:284 #5 syscall+0x552 mi_syscall sys/sys/syscall_mi.h:92 [inline] #5 syscall+0x552 sys/arch/amd64/amd64/trap.c:555 #6 Xsyscall+0x128 exclusive mutex /syzkaller/managers/multicore/kernel/sys/netinet6/frag6.c:57 r = 0 (0xffffffff824bae40) #0 witness_lock+0x52e sys/kern/subr_witness.c:1163 #1 mtx_enter_try+0x102 #2 mtx_enter+0x4b sys/kern/kern_lock.c:266 #3 frag6_input+0x237 sys/netinet6/frag6.c:183 #4 ip_deliver+0x353 sys/netinet/ip_input.c:665 #5 ip6_input_if+0x17d4 ip6_ours sys/netinet6/ip6_input.c:518 [inline] #5 ip6_input_if+0x17d4 sys/netinet6/ip6_input.c:340 #6 ipv6_input+0x48 sys/netinet6/ip6_input.c:171 #7 if_input_local+0x121 sys/net/if.c:783 #8 ip6_output+0xd59 #9 rip6_output+0x4c0 sys/netinet6/raw_ip6.c:481 #10 rip6_usrreq+0x5cd sys/netinet6/raw_ip6.c:670 #11 sosend+0x668 sys/kern/uipc_socket.c:524 #12 dofilewritev+0x1ac sys/kern/sys_generic.c:364 #13 sys_write+0x83 sys/kern/sys_generic.c:284 #14 syscall+0x552 mi_syscall sys/sys/syscall_mi.h:92 [inline] #14 syscall+0x552 sys/arch/amd64/amd64/trap.c:555 #15 Xsyscall+0x128 ddb{0}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim Kern Lim devbuf 9561 6434K 7200K 78643K 15884 0 0 pcb 14 8K 8K 78643K 291 0 0 rtable 86 3K 4K 78643K 683 0 0 ifaddr 69 15K 17K 78643K 271 0 0 counters 39 33K 33K 78643K 39 0 0 ioctlops 0 0K 4K 78643K 1550 0 0 iov 0 0K 16K 78643K 204 0 0 mount 1 1K 1K 78643K 1 0 0 vnodes 1211 76K 77K 78643K 3100 0 0 UFS quota 1 32K 32K 78643K 1 0 0 UFS mount 5 36K 36K 78643K 5 0 0 shm 2 1K 5K 78643K 33 0 0 VM map 2 1K 1K 78643K 3 0 0 sem 12 0K 1K 78643K 243 0 0 dirhash 12 2K 2K 78643K 12 0 0 ACPI 1808 196K 290K 78643K 12765 0 0 file desc 6 17K 25K 78643K 2048 0 0 sigio 0 0K 0K 78643K 38 0 0 proc 53 50K 83K 78643K 755 0 0 subproc 32 2K 2K 78643K 85 0 0 NFS srvsock 1 0K 0K 78643K 1 0 0 NFS daemon 1 16K 16K 78643K 1 0 0 ip_moptions 0 0K 0K 78643K 147 0 0 in_multi 22 1K 2K 78643K 140 0 0 ether_multi 1 0K 0K 78643K 11 0 0 mrt 0 0K 0K 78643K 14 0 0 ISOFS mount 1 32K 32K 78643K 1 0 0 MSDOSFS mount 1 16K 16K 78643K 1 0 0 ttys 84 371K 371K 78643K 84 0 0 exec 0 0K 1K 78643K 435 0 0 pfkey data 0 0K 0K 78643K 1 0 0 pagedep 1 8K 8K 78643K 1 0 0 inodedep 1 32K 32K 78643K 1 0 0 newblk 1 0K 0K 78643K 1 0 0 VM swap 7 26K 26K 78643K 7 0 0 UVM amap 102 21K 30K 78643K 7519 0 0 UVM aobj 72 5K 5K 78643K 86 0 0 memdesc 1 4K 4K 78643K 1 0 0 crypto data 1 1K 1K 78643K 1 0 0 ip6_options 2 0K 0K 78643K 266 0 0 NDP 16 0K 0K 78643K 77 0 0 temp 201 3556K 3628K 78643K 24295 0 0 kqueue 0 0K 0K 78643K 6 0 0 SYN cache 2 16K 16K 78643K 2 0 0 ddb{0}> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle arp 64 12 0 8 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtpcb 80 73 0 71 1 0 1 1 0 8 0 rtentry 112 83 0 50 2 0 2 2 0 8 0 unpcb 120 641 0 631 1 0 1 1 0 8 0 syncache 264 4 0 4 1 1 0 1 0 8 0 tcpqe 32 5724 0 5724 1 1 0 1 0 8 0 tcpcb 544 440 0 435 1 0 1 1 0 8 0 inpcb 280 1265 0 1257 1 0 1 1 0 8 0 rttmr 72 3 0 3 3 3 0 1 0 8 0 ip6q 72 1 0 0 1 0 1 1 0 8 0 ip6af 48 1 0 0 1 0 1 1 0 8 0 nd6 48 15 0 12 1 0 1 1 0 8 0 pkpcb 40 6 0 6 3 2 1 1 0 8 1 ppxss 1128 39 0 39 7 6 1 1 0 8 1 pffrag 232 7 0 7 3 3 0 1 0 482 0 pffrnode 88 7 0 7 3 3 0 1 0 8 0 pffrent 40 16 0 16 3 3 0 1 0 8 0 pfosfp 40 846 0 423 5 0 5 5 0 8 0 pfosfpen 112 1428 0 714 21 0 21 21 0 8 0 pfstitem 24 76 0 51 1 0 1 1 0 8 0 pfstkey 112 76 0 51 1 0 1 1 0 8 0 pfstate 328 76 0 51 3 0 3 3 0 8 0 pfrule 1360 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 256 330 0 182 12 0 12 12 0 8 0 art_table 32 331 0 182 2 0 2 2 0 8 0 art_node 16 80 0 50 1 0 1 1 0 8 0 sysvmsgpl 40 10 0 8 2 1 1 1 0 8 0 semapl 112 241 0 231 1 0 1 1 0 8 0 shmpl 112 84 0 14 2 0 2 2 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 4658 0 3241 47 0 47 47 0 8 0 ffsino 272 4658 0 3241 96 0 96 96 0 8 0 nchpl 144 7812 0 6181 62 0 62 62 0 8 0 uvmvnodes 72 5926 0 0 108 0 108 108 0 8 0 vnodes 200 5926 0 0 312 0 312 312 0 8 0 namei 1024 24681 0 24681 2 1 1 1 0 8 1 percpumem 16 30 0 0 1 0 1 1 0 8 0 vmpool 552 1 0 1 1 1 0 1 0 8 0 scsiplug 64 4 0 4 3 3 0 1 0 8 0 scxspl 192 22048 0 22048 17 16 1 7 0 8 1 plimitpl 152 200 0 192 1 0 1 1 0 8 0 sigapl 432 2240 0 2224 3 1 2 3 0 8 0 futexpl 56 27032 0 27032 1 0 1 1 0 8 1 knotepl 112 411 0 392 1 0 1 1 0 8 0 kqueuepl 104 494 0 492 1 0 1 1 0 8 0 pipepl 112 1278 0 1259 2 1 1 2 0 8 0 fdescpl 488 2241 0 2224 3 0 3 3 0 8 0 filepl 152 13422 0 13322 8 3 5 7 0 8 0 lockfpl 104 617 0 617 2 1 1 1 0 8 1 lockfspl 48 212 0 212 2 1 1 1 0 8 1 sessionpl 112 22 0 11 1 0 1 1 0 8 0 pgrppl 48 47 0 36 1 0 1 1 0 8 0 ucredpl 96 2513 0 2504 1 0 1 1 0 8 0 zombiepl 144 2224 0 2224 2 1 1 1 0 8 1 processpl 896 2257 0 2224 4 0 4 4 0 8 0 procpl 632 6582 0 6538 10 5 5 5 0 8 1 srpgc 64 11 0 11 7 6 1 1 0 8 1 sosppl 128 10 0 10 3 2 1 1 0 8 1 sockpl 384 2008 0 1988 5 2 3 4 0 8 0 mcl64k 65536 519 0 0 65 6 59 65 0 8 1 mcl16k 16384 2 0 0 1 0 1 1 0 8 0 mcl12k 12288 15 0 0 2 0 2 2 0 8 0 mcl9k 9216 7 0 0 1 0 1 1 0 8 0 mcl8k 8192 10 0 0 2 0 2 2 0 8 0 mcl4k 4096 13 0 0 2 0 2 2 0 8 0 mcl2k2 2112 6 0 0 1 0 1 1 0 8 0 mcl2k 2048 164 0 0 20 0 20 20 0 8 0 mtagpl 80 41 0 0 1 0 1 1 0 8 0 mbufpl 256 683 0 0 38 0 38 38 0 8 0 bufpl 256 10141 0 3122 439 0 439 439 0 8 0 anonpl 16 224608 0 211891 111 53 58 69 0 124 3 amapchunkpl 152 12951 0 12832 21 11 10 10 0 158 4 amappl16 192 11662 0 10960 93 57 36 48 0 8 0 amappl15 184 13 0 11 1 0 1 1 0 8 0 amappl14 176 159 0 152 1 0 1 1 0 8 0 amappl13 168 699 0 699 2 2 0 1 0 8 0 amappl12 160 128 0 127 2 1 1 1 0 8 0 amappl11 152 68 0 53 1 0 1 1 0 8 0 amappl10 144 1060 0 1054 1 0 1 1 0 8 0 amappl9 136 640 0 637 1 0 1 1 0 8 0 amappl8 128 201 0 178 1 0 1 1 0 8 0 amappl7 120 1026 0 1016 1 0 1 1 0 8 0 amappl6 112 70 0 63 1 0 1 1 0 8 0 amappl5 104 287 0 270 1 0 1 1 0 8 0 amappl4 96 2393 0 2360 2 1 1 2 0 8 0 amappl3 88 449 0 438 1 0 1 1 0 8 0 amappl2 80 17529 0 17448 3 0 3 3 0 8 0 amappl1 72 57742 0 57297 25 15 10 20 0 8 0 amappl 80 6883 0 6842 2 0 2 2 0 84 0 dma4096 4096 1 0 1 1 1 0 1 0 8 0 dma256 256 6 0 6 1 1 0 1 0 8 0 dma64 64 259 0 259 1 1 0 1 0 8 0 dma32 32 7 0 7 1 1 0 1 0 8 0 dma16 16 17 0 17 1 1 0 1 0 8 0 aobjpl 64 85 0 14 2 0 2 2 0 8 0 uaddrrnd 24 2242 0 2224 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 2242 0 2224 1 0 1 1 0 8 0 vmmpekpl 168 17844 0 17809 2 0 2 2 0 8 0 vmmpepl 168 277676 0 275738 177 76 101 105 0 357 16 vmsppl 368 2240 0 2224 2 0 2 2 0 8 0 pdppl 4096 4491 0 4450 7 1 6 6 0 8 0 pvpl 32 602687 0 586717 234 83 151 168 0 265 16 pmappl 232 2241 0 2225 2 1 1 2 0 8 0 extentpl 40 41 0 26 1 0 1 1 0 8 0 phpool 112 695 0 11 20 0 20 20 0 8 0