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 *488625 5216 0 0 0x4000000 1 syz-executor.0 284593 89812 0 0x14000 0x40000200 0 softclock 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(ffffffff82672640,9,0) at witness_checkorder+0x10cc sys/kern/subr_witness.c:820 __mp_lock(ffffffff82672438) at __mp_lock+0xa1 pageflttrap() at pageflttrap+0x6f sys/arch/amd64/amd64/trap.c:162 kerntrap(ffff800020b494a0) at kerntrap+0xec sys/arch/amd64/amd64/trap.c:287 alltraps_kern_meltdown(6,0,600,0,fffffd806f654054,fffffd80673dbf40) at alltraps_kern_meltdown+0x7b frag6_input(ffff800020b49808,ffff800020b49814,2c,18) at frag6_input+0x7d2 sys/netinet6/frag6.c:321 ip_deliver(ffff800020b49808,ffff800020b49814,2c,18) at ip_deliver+0x353 sys/netinet/ip_input.c:665 ip6_input_if(ffff800020b49808,ffff800020b49814,29,0,ffff80000066d000) at ip6_input_if+0x17d4 ip6_ours sys/netinet6/ip6_input.c:518 [inline] ip6_input_if(ffff800020b49808,ffff800020b49814,29,0,ffff80000066d000) at ip6_input_if+0x17d4 sys/netinet6/ip6_input.c:340 ipv6_input(ffff80000066d000,fffffd806d785300) at ipv6_input+0x48 sys/netinet6/ip6_input.c:171 if_input_local(ffff80000066d000,fffffd806d785300,18) at if_input_local+0x121 sys/net/if.c:783 ip6_output(fffffd806d49c300,ffff800000a9bf00,fffffd806f6bdc78,0,0,fffffd806f6bdc08) at ip6_output+0xd59 rip6_output(fffffd806d49c300,fffffd807cbc8aa0,ffff800020b49b78,0) at rip6_output+0x4c0 sys/netinet6/raw_ip6.c:481 end trace frame: 0xffff800020b49c10, 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{1}> ddb{1}> set $lines = 0 ddb{1}> set $maxwidth = 0 ddb{1}> show panic acquiring blockable sleep lock with spinlock or critical section held (kernel_lock) &kernel_lock ddb{1}> 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(ffffffff82672640,9,0) at witness_checkorder+0x10cc sys/kern/subr_witness.c:820 __mp_lock(ffffffff82672438) at __mp_lock+0xa1 pageflttrap() at pageflttrap+0x6f sys/arch/amd64/amd64/trap.c:162 kerntrap(ffff800020b494a0) at kerntrap+0xec sys/arch/amd64/amd64/trap.c:287 alltraps_kern_meltdown(6,0,600,0,fffffd806f654054,fffffd80673dbf40) at alltraps_kern_meltdown+0x7b frag6_input(ffff800020b49808,ffff800020b49814,2c,18) at frag6_input+0x7d2 sys/netinet6/frag6.c:321 ip_deliver(ffff800020b49808,ffff800020b49814,2c,18) at ip_deliver+0x353 sys/netinet/ip_input.c:665 ip6_input_if(ffff800020b49808,ffff800020b49814,29,0,ffff80000066d000) at ip6_input_if+0x17d4 ip6_ours sys/netinet6/ip6_input.c:518 [inline] ip6_input_if(ffff800020b49808,ffff800020b49814,29,0,ffff80000066d000) at ip6_input_if+0x17d4 sys/netinet6/ip6_input.c:340 ipv6_input(ffff80000066d000,fffffd806d785300) at ipv6_input+0x48 sys/netinet6/ip6_input.c:171 if_input_local(ffff80000066d000,fffffd806d785300,18) at if_input_local+0x121 sys/net/if.c:783 ip6_output(fffffd806d49c300,ffff800000a9bf00,fffffd806f6bdc78,0,0,fffffd806f6bdc08) at ip6_output+0xd59 rip6_output(fffffd806d49c300,fffffd807cbc8aa0,ffff800020b49b78,0) at rip6_output+0x4c0 sys/netinet6/raw_ip6.c:481 rip6_usrreq(fffffd807cbc8aa0,9,fffffd806d49c300,0,0,ffff800020a5e770) at rip6_usrreq+0x5cd sys/netinet6/raw_ip6.c:670 sosend(fffffd807cbc8aa0,0,ffff800020b49da8,0,0,0) at sosend+0x668 sys/kern/uipc_socket.c:524 dofilewritev(ffff800020a5e770,3,ffff800020b49da8,0,ffff800020b49eb0) at dofilewritev+0x1ac sys/kern/sys_generic.c:364 sys_write(ffff800020a5e770,ffff800020b49e48,ffff800020b49eb0) at sys_write+0x83 sys/kern/sys_generic.c:284 syscall(ffff800020b49f20) at syscall+0x552 mi_syscall sys/sys/syscall_mi.h:92 [inline] syscall(ffff800020b49f20) at syscall+0x552 sys/arch/amd64/amd64/trap.c:555 Xsyscall(6,0,c,0,3,a7bc9c2a010) at Xsyscall+0x128 end of kernel end trace frame: 0xa7e39f4e970, count: -20 ddb{1}> show registers rdi 0xffffffff81be0707 db_enter+0x17 rsi 0x3740 __ALIGN_SIZE+0x2740 rbp 0xffff800020b49200 rbx 0xffff800020b492b0 rdx 0x3741 __ALIGN_SIZE+0x2741 rcx 0xffff800022964000 rax 0xffff800022964000 r8 0xffffffff81da97e3 kprintf+0x173 r9 0x1 r10 0x25 r11 0xa1c14167e2e6d570 r12 0x3000000008 r13 0xffff800020b49210 r14 0x100 r15 0x1 rip 0xffffffff81be0708 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800020b491f0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor.0) pid=488625 stat=onproc flags process=0 proc=4000000 pri=79, usrpri=79, nice=20 forw=0xffffffffffffffff, list=0xffff800020ac0778,0xffffffff82655a00 process=0xffff800020adc700 user=0xffff800020b44000, vmspace=0xfffffd807f00c000 estcpu=36, cpticks=1, pctcpu=0.0 user=0, sys=1, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 5216 12777 5303 0 2 0 syz-executor.0 * 5216 488625 5303 0 7 0x4000000 syz-executor.0 5303 69806 79437 0 3 0x82 nanosleep syz-executor.0 36682 459573 1 0 3 0x100083 ttyin getty 80535 8425 0 0 3 0x14200 bored sosplice 35025 372055 79437 0 2 0x482 syz-executor.1 79437 309067 47791 0 3 0x82 thrsleep syz-fuzzer 79437 339087 47791 0 3 0x4000082 nanosleep syz-fuzzer 79437 70056 47791 0 3 0x4000082 thrsleep syz-fuzzer 79437 92891 47791 0 3 0x4000082 thrsleep syz-fuzzer 79437 177824 47791 0 3 0x4000082 thrsleep syz-fuzzer 79437 281867 47791 0 3 0x4000082 kqread syz-fuzzer 79437 9473 47791 0 3 0x4000082 nanosleep syz-fuzzer 79437 399494 47791 0 3 0x4000082 thrsleep syz-fuzzer 79437 298125 47791 0 3 0x4000082 thrsleep syz-fuzzer 79437 270007 47791 0 3 0x4000082 thrsleep syz-fuzzer 47791 119414 69539 0 3 0x10008a pause ksh 69539 340516 97505 0 3 0x92 select sshd 97505 136362 1 0 3 0x80 select sshd 80718 297231 80844 74 3 0x100092 bpf pflogd 80844 188940 1 0 3 0x80 netio pflogd 83512 94369 34716 73 3 0x100090 kqread syslogd 34716 64067 1 0 3 0x100082 netio syslogd 40773 105413 1 77 3 0x100090 poll dhclient 14986 115865 1 0 3 0x80 poll dhclient 98897 359853 0 0 3 0x14200 pgzero zerothread 58416 218664 0 0 3 0x14200 aiodoned aiodoned 70457 123058 0 0 3 0x14200 syncer update 4936 434934 0 0 3 0x14200 cleaner cleaner 15463 352324 0 0 3 0x14200 reaper reaper 63096 502228 0 0 3 0x14200 pgdaemon pagedaemon 51044 292319 0 0 3 0x14200 bored crynlk 34843 59205 0 0 3 0x14200 bored crypto 93558 113283 0 0 3 0x40014200 acpi0 acpi0 10873 238911 0 0 3 0x40014200 idle1 72899 296126 0 0 3 0x14200 bored softnet 30926 94345 0 0 3 0x14200 bored systqmp 15094 338479 0 0 3 0x14200 bored systq 89812 284593 0 0 7 0x40014200 softclock 69596 404333 0 0 3 0x40014200 idle0 35598 331330 0 0 3 0x14200 bored smr 1 141194 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/netinet6/frag6.c:57 r = 0 (0xffffffff82484090) #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 5216 (syz-executor.0) thread 0xffff800020a5e770 (488625) exclusive rwlock netlock r = 0 (0xffffffff824be8a8) #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 (0xffffffff82484090) #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{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim Kern Lim devbuf 9556 6448K 7094K 78643K 14221 0 0 pcb 14 8K 8K 78643K 178 0 0 rtable 111 4K 5K 78643K 587 0 0 ifaddr 68 14K 15K 78643K 199 0 0 counters 39 33K 33K 78643K 39 0 0 ioctlops 0 0K 4K 78643K 1517 0 0 iov 0 0K 32K 78643K 123 0 0 mount 1 1K 1K 78643K 1 0 0 vnodes 1216 76K 77K 78643K 2518 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 22 0 0 VM map 2 1K 1K 78643K 2 0 0 sem 12 1K 1K 78643K 124 0 0 dirhash 12 2K 2K 78643K 12 0 0 ACPI 1808 196K 290K 78643K 12765 0 0 file desc 5 13K 25K 78643K 1411 0 0 sigio 0 0K 0K 78643K 15 0 0 proc 53 50K 83K 78643K 704 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 110 0 0 in_multi 33 2K 2K 78643K 111 0 0 ether_multi 1 0K 0K 78643K 9 0 0 mrt 0 0K 0K 78643K 10 0 0 ISOFS mount 1 32K 32K 78643K 1 0 0 MSDOSFS mount 1 16K 16K 78643K 1 0 0 ttys 90 397K 397K 78643K 90 0 0 exec 0 0K 1K 78643K 354 0 0 pfkey data 0 0K 4K 78643K 2 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 98 21K 30K 78643K 5344 0 0 UVM aobj 45 2K 2K 78643K 49 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 130 0 0 NDP 15 0K 0K 78643K 58 0 0 temp 194 3556K 3627K 78643K 9891 0 0 kqueue 0 0K 0K 78643K 12 0 0 SYN cache 2 16K 16K 78643K 2 0 0 ddb{1}> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle arp 64 12 0 6 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtpcb 80 74 0 72 1 0 1 1 0 8 0 rtentry 112 80 0 36 2 0 2 2 0 8 0 unpcb 120 485 0 475 1 0 1 1 0 8 0 syncache 264 4 0 4 1 1 0 1 0 8 0 tcpqe 32 1648 0 1648 1 1 0 1 0 8 0 tcpcb 544 246 0 241 1 0 1 1 0 8 0 inpcb 280 784 0 776 2 1 1 2 0 8 0 rttmr 72 2 0 2 1 1 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 9 1 0 1 1 0 8 0 pkpcb 40 17 0 17 4 3 1 1 0 8 1 ppxss 1128 24 0 24 5 4 1 1 0 8 1 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 39 0 27 1 0 1 1 0 8 0 pfstkey 112 39 0 27 1 0 1 1 0 8 0 pfstate 328 39 0 27 2 0 2 2 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 256 352 0 160 14 2 12 14 0 8 0 art_table 32 353 0 160 2 0 2 2 0 8 0 art_node 16 79 0 39 1 0 1 1 0 8 0 sysvmsgpl 40 7 0 5 1 0 1 1 0 8 0 semupl 112 1 0 1 1 1 0 1 0 8 0 semapl 112 120 0 110 1 0 1 1 0 8 0 shmpl 112 47 0 4 2 0 2 2 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 3613 0 2194 47 0 47 47 0 8 0 ffsino 272 3613 0 2194 96 0 96 96 0 8 0 nchpl 144 5761 0 4125 62 0 62 62 0 8 0 uvmvnodes 72 4554 0 0 83 0 83 83 0 8 0 vnodes 200 4554 0 0 240 0 240 240 0 8 0 namei 1024 18014 0 18014 2 1 1 1 0 8 1 percpumem 16 30 0 0 1 0 1 1 0 8 0 scxspl 192 15613 0 15613 14 11 3 7 0 8 3 plimitpl 152 154 0 146 1 0 1 1 0 8 0 sigapl 432 1603 0 1588 3 1 2 3 0 8 0 futexpl 56 18142 0 18142 1 0 1 1 0 8 1 knotepl 112 336 0 317 1 0 1 1 0 8 0 kqueuepl 104 289 0 287 1 0 1 1 0 8 0 pipepl 112 938 0 919 3 2 1 2 0 8 0 fdescpl 488 1604 0 1588 3 0 3 3 0 8 0 filepl 152 9353 0 9253 9 4 5 7 0 8 1 lockfpl 104 374 0 374 2 1 1 1 0 8 1 lockfspl 48 145 0 145 2 1 1 1 0 8 1 sessionpl 112 22 0 11 1 0 1 1 0 8 0 pgrppl 48 30 0 19 1 0 1 1 0 8 0 ucredpl 96 1642 0 1633 1 0 1 1 0 8 0 zombiepl 144 1588 0 1587 2 1 1 1 0 8 0 processpl 896 1620 0 1587 4 0 4 4 0 8 0 procpl 632 4422 0 4379 6 1 5 5 0 8 1 srpgc 64 8 0 8 3 3 0 1 0 8 0 sosppl 128 22 0 22 3 3 0 1 0 8 0 sockpl 384 1376 0 1356 5 2 3 4 0 8 0 mcl64k 65536 17 0 0 3 0 3 3 0 8 0 mcl16k 16384 5 0 0 1 0 1 1 0 8 0 mcl12k 12288 11 0 0 2 0 2 2 0 8 0 mcl9k 9216 4 0 0 1 0 1 1 0 8 0 mcl8k 8192 5 0 0 1 0 1 1 0 8 0 mcl4k 4096 8 0 0 1 0 1 1 0 8 0 mcl2k2 2112 3 0 0 1 0 1 1 0 8 0 mcl2k 2048 104 0 0 12 0 12 12 0 8 0 mtagpl 80 26 0 0 1 0 1 1 0 8 0 mbufpl 256 182 0 0 9 0 9 9 0 8 0 bufpl 256 9219 0 2200 439 0 439 439 0 8 0 anonpl 16 156666 0 143817 83 29 54 69 0 124 0 amapchunkpl 152 9321 0 9219 18 13 5 10 0 158 0 amappl16 192 7435 0 6719 65 27 38 48 0 8 2 amappl15 184 8 0 7 1 0 1 1 0 8 0 amappl14 176 70 0 64 1 0 1 1 0 8 0 amappl13 168 68 0 68 2 2 0 1 0 8 0 amappl12 160 20 0 19 1 0 1 1 0 8 0 amappl11 152 700 0 683 1 0 1 1 0 8 0 amappl10 144 738 0 734 1 0 1 1 0 8 0 amappl9 136 561 0 558 1 0 1 1 0 8 0 amappl8 128 185 0 165 1 0 1 1 0 8 0 amappl7 120 705 0 699 1 0 1 1 0 8 0 amappl6 112 669 0 661 1 0 1 1 0 8 0 amappl5 104 314 0 300 1 0 1 1 0 8 0 amappl4 96 1880 0 1850 2 1 1 2 0 8 0 amappl3 88 226 0 216 1 0 1 1 0 8 0 amappl2 80 11969 0 11895 3 1 2 3 0 8 0 amappl1 72 42504 0 42070 26 16 10 20 0 8 0 amappl 80 4728 0 4692 1 0 1 1 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 48 0 4 1 0 1 1 0 8 0 uaddrrnd 24 1604 0 1588 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 1604 0 1588 1 0 1 1 0 8 0 vmmpekpl 168 15945 0 15910 2 0 2 2 0 8 0 vmmpepl 168 198749 0 196916 148 48 100 106 0 357 16 vmsppl 368 1603 0 1588 2 0 2 2 0 8 0 pdppl 4096 3215 0 3176 7 1 6 6 0 8 1 pvpl 32 441812 0 425790 190 48 142 168 0 265 8 pmappl 232 1603 0 1588 2 1 1 2 0 8 0 extentpl 40 41 0 26 1 0 1 1 0 8 0 phpool 112 596 0 7 17 0 17 17 0 8 0