panic: pool_cache_item_magic_check: mbufpl cpu free list modified: item addr 0xfffffd807a28a100+16 0x0!=0x5b12f2b7c37ff385 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *342574 90074 0 0 0x4000000 1 syz-executor.1 193340 97583 0 0 0x4000080 0 syz-executor.0 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic() at panic+0x15c sys/kern/subr_prf.c:207 pool_cache_get(ffffffff826766b8) at pool_cache_get+0x323 pool_cache_item_magic_check sys/kern/subr_pool.c:1789 [inline] pool_cache_get(ffffffff826766b8) at pool_cache_get+0x323 sys/kern/subr_pool.c:1892 pool_get() at pool_get+0x91 sys/kern/subr_pool.c:572 m_copym(fffffd806909a600,f794,574,2) at m_copym+0x174 m_get sys/kern/uipc_mbuf.c:250 [inline] m_copym(fffffd806909a600,f794,574,2) at m_copym+0x174 sys/kern/uipc_mbuf.c:667 ip_fragment(fffffd806909a600,ffff8000001732a8,5b4) at ip_fragment+0x324 ip_output(fffffd806909a600,0,fffffd806f6cf700,0,0,fffffd806f6cf690) at ip_output+0xfc1 sys/netinet/ip_output.c:501 udp_output(fffffd806f6cf690,fffffd806909a600,0,0) at udp_output+0x5af sys/netinet/udp_usrreq.c:1004 sosend(fffffd8062a7e330,0,ffff8000239a34e0,0,0,0) at sosend+0x645 sys/kern/uipc_socket.c:524 sendit(ffff800020acea10,6,ffff8000239a35c0,0,ffff8000239a36a0) at sendit+0x52b sys/kern/uipc_syscalls.c:662 sys_sendto(ffff800020acea10,ffff8000239a3658,ffff8000239a36a0) at sys_sendto+0x80 sys/kern/uipc_syscalls.c:527 syscall(ffff8000239a3720) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:92 [inline] syscall(ffff8000239a3720) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:555 Xsyscall(6,0,ffffffffffffffd7,0,6,c775e332010) at Xsyscall+0x128 end of kernel end trace frame: 0xc79c515ab20, count: 2 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 pool_cache_item_magic_check: mbufpl cpu free list modified: item addr 0xfffffd807a28a100+16 0x0!=0x5b12f2b7c37ff385 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 pool_cache_get(ffffffff826766b8) at pool_cache_get+0x323 pool_cache_item_magic_check sys/kern/subr_pool.c:1789 [inline] pool_cache_get(ffffffff826766b8) at pool_cache_get+0x323 sys/kern/subr_pool.c:1892 pool_get() at pool_get+0x91 sys/kern/subr_pool.c:572 m_copym(fffffd806909a600,f794,574,2) at m_copym+0x174 m_get sys/kern/uipc_mbuf.c:250 [inline] m_copym(fffffd806909a600,f794,574,2) at m_copym+0x174 sys/kern/uipc_mbuf.c:667 ip_fragment(fffffd806909a600,ffff8000001732a8,5b4) at ip_fragment+0x324 ip_output(fffffd806909a600,0,fffffd806f6cf700,0,0,fffffd806f6cf690) at ip_output+0xfc1 sys/netinet/ip_output.c:501 udp_output(fffffd806f6cf690,fffffd806909a600,0,0) at udp_output+0x5af sys/netinet/udp_usrreq.c:1004 sosend(fffffd8062a7e330,0,ffff8000239a34e0,0,0,0) at sosend+0x645 sys/kern/uipc_socket.c:524 sendit(ffff800020acea10,6,ffff8000239a35c0,0,ffff8000239a36a0) at sendit+0x52b sys/kern/uipc_syscalls.c:662 sys_sendto(ffff800020acea10,ffff8000239a3658,ffff8000239a36a0) at sys_sendto+0x80 sys/kern/uipc_syscalls.c:527 syscall(ffff8000239a3720) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:92 [inline] syscall(ffff8000239a3720) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:555 Xsyscall(6,0,ffffffffffffffd7,0,6,c775e332010) at Xsyscall+0x128 end of kernel end trace frame: 0xc79c515ab20, count: -13 ddb{1}> show registers rdi 0xffffffff81c88787 db_enter+0x17 rsi 0x8b66 __ALIGN_SIZE+0x7b66 rbp 0xffff8000239a2ef0 rbx 0xffff8000239a2fa0 rdx 0x8b67 __ALIGN_SIZE+0x7b67 rcx 0xffff800020d58000 rax 0xffff800020d58000 r8 0xffffffff8215dd5f kprintf+0x16f r9 0x1 r10 0x25 r11 0xef47675aa42fbbe5 r12 0x3000000008 r13 0xffff8000239a2f00 r14 0x100 r15 0x1 rip 0xffffffff81c88788 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff8000239a2ee0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor.1) pid=342574 stat=onproc flags process=0 proc=4000000 pri=86, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff800020acf668,0xffffffff82671458 process=0xffff800020adc000 user=0xffff80002399e000, vmspace=0xfffffd807f00b000 estcpu=36, cpticks=1, pctcpu=0.0 user=0, sys=1, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 90074 344462 66384 0 2 0 syz-executor.1 *90074 342574 66384 0 7 0x4000000 syz-executor.1 97583 185249 36187 0 2 0 syz-executor.0 97583 193340 36187 0 7 0x4000080 syz-executor.0 97583 236784 36187 0 3 0x4000080 fsleep syz-executor.0 97583 46453 36187 0 3 0x4000080 fsleep syz-executor.0 66384 337862 72487 0 3 0x82 nanosleep syz-executor.1 36187 524274 72487 0 3 0x82 nanosleep syz-executor.0 18394 122980 1 0 3 0x100083 ttyin getty 21359 265101 0 0 3 0x14200 acct acct 26764 290847 0 0 3 0x14200 bored sosplice 72487 410697 85289 0 3 0x82 nanosleep syz-fuzzer 72487 64289 85289 0 3 0x4000082 nanosleep syz-fuzzer 72487 360973 85289 0 3 0x4000082 thrsleep syz-fuzzer 72487 363102 85289 0 3 0x4000082 thrsleep syz-fuzzer 72487 498600 85289 0 3 0x4000082 thrsleep syz-fuzzer 72487 143611 85289 0 3 0x4000082 thrsleep syz-fuzzer 72487 347463 85289 0 3 0x4000082 thrsleep syz-fuzzer 72487 449004 85289 0 3 0x4000082 thrsleep syz-fuzzer 72487 76411 85289 0 3 0x4000082 thrsleep syz-fuzzer 72487 58187 85289 0 3 0x4000082 kqread syz-fuzzer 85289 135959 77543 0 3 0x10008a pause ksh 77543 517112 1883 0 3 0x92 select sshd 1883 146574 1 0 3 0x80 select sshd 22734 94930 92972 74 3 0x100092 bpf pflogd 92972 486425 1 0 3 0x80 netio pflogd 26862 283955 74554 73 3 0x100090 kqread syslogd 74554 72799 1 0 3 0x100082 netio syslogd 1107 448299 1 77 3 0x100090 poll dhclient 77611 112834 1 0 3 0x80 poll dhclient 8459 238293 0 0 2 0x14200 zerothread 28136 270596 0 0 3 0x14200 aiodoned aiodoned 17982 460614 0 0 3 0x14200 syncer update 29477 507869 0 0 3 0x14200 cleaner cleaner 54457 288636 0 0 3 0x14200 reaper reaper 26321 320579 0 0 3 0x14200 pgdaemon pagedaemon 82058 239646 0 0 3 0x14200 bored crynlk 40675 51679 0 0 3 0x14200 bored crypto 28200 190714 0 0 3 0x40014200 acpi0 acpi0 48077 514392 0 0 3 0x40014200 idle1 28049 184774 0 0 3 0x14200 bored softnet 93164 338897 0 0 3 0x14200 bored systqmp 39627 369048 0 0 3 0x14200 bored systq 26679 158496 0 0 3 0x40014200 bored softclock 18157 2595 0 0 3 0x40014200 idle0 37253 135235 0 0 3 0x14200 bored smr 1 22492 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks Process 90074 (syz-executor.1) thread 0xffff800020acea10 (342574) exclusive rwlock netlock r = 0 (0xffffffff824a2a68) #0 witness_lock+0x52e sys/kern/subr_witness.c:1163 #1 solock+0x5a sys/kern/uipc_socket2.c:282 #2 sosend+0x51b sys/kern/uipc_socket.c:512 #3 sendit+0x52b sys/kern/uipc_syscalls.c:662 #4 sys_sendto+0x80 sys/kern/uipc_syscalls.c:527 #5 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:92 [inline] #5 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:555 #6 Xsyscall+0x128 ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim Kern Lim devbuf 9626 6460K 7934K 78643K 18338 0 0 pcb 13 10K 12K 78643K 652 0 0 rtable 87 12K 14K 78643K 2045 0 0 ifaddr 108 24K 26K 78643K 775 0 0 counters 39 33K 33K 78643K 39 0 0 ioctlops 0 0K 4K 78643K 1691 0 0 iov 0 0K 32K 78643K 706 0 0 mount 1 1K 1K 78643K 1 0 0 vnodes 1220 77K 77K 78643K 4072 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 54 0 0 VM map 21 10K 11K 78643K 42 0 0 sem 12 0K 1K 78643K 689 0 0 dirhash 12 2K 2K 78643K 12 0 0 ACPI 1808 196K 290K 78643K 12765 0 0 file desc 6 17K 25K 78643K 3349 0 0 sigio 0 0K 0K 78643K 283 0 0 proc 62 63K 83K 78643K 1482 0 0 subproc 32 2K 2K 78643K 310 0 0 NFS srvsock 1 0K 0K 78643K 1 0 0 NFS daemon 1 16K 16K 78643K 1 0 0 ip_moptions 0 0K 1K 78643K 310 0 0 in_multi 22 1K 2K 78643K 353 0 0 ether_multi 1 0K 0K 78643K 26 0 0 mrt 0 0K 0K 78643K 15 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 822 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 149 185K 201K 78643K 12824 0 0 UVM aobj 130 8K 8K 78643K 141 0 0 memdesc 1 4K 4K 78643K 1 0 0 crypto data 1 1K 1K 78643K 1 0 0 ip6_options 0 0K 1K 78643K 724 0 0 NDP 23 0K 1K 78643K 216 0 0 temp 250 3561K 4200K 78643K 77435 0 0 kqueue 0 0K 0K 78643K 51 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 38 0 34 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtpcb 80 245 0 243 1 0 1 1 0 8 0 rtentry 112 294 0 268 2 0 2 2 0 8 0 unpcb 120 1738 0 1723 4 3 1 2 0 8 0 syncache 264 22 0 22 9 8 1 1 0 8 1 sackhl 24 2 0 2 2 2 0 1 0 8 0 tcpqe 32 7319 0 7319 6 6 0 2 0 8 0 tcpcb 544 1262 0 1258 6 5 1 4 0 8 0 inpcb 280 9481 0 9473 29 26 3 13 0 8 2 rttmr 72 5 0 5 4 4 0 1 0 8 0 ip6q 72 4 0 3 3 2 1 1 0 8 0 ip6af 40 10 0 9 3 2 1 1 0 8 0 nd6 48 45 0 45 2 1 1 1 0 8 1 pkpcb 40 5 0 5 3 3 0 1 0 8 0 ppxss 1128 109 0 109 10 9 1 1 0 8 1 pffrag 232 54 0 54 12 11 1 1 0 482 1 pffrnode 88 54 0 54 12 11 1 1 0 8 1 pffrent 40 1064 0 1064 12 11 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 24 243 0 194 1 0 1 1 0 8 0 pfstkey 112 243 0 194 2 0 2 2 0 8 0 pfstate 328 243 0 194 5 0 5 5 0 8 0 pfrule 1360 21 0 16 2 1 1 2 0 8 0 art_heap8 4096 11 0 10 6 5 1 4 0 8 0 art_heap4 256 1334 0 1204 18 5 13 15 0 8 0 art_table 32 1345 0 1214 2 0 2 2 0 8 0 art_node 16 290 0 266 1 0 1 1 0 8 0 sysvmsgpl 40 64 0 44 1 0 1 1 0 8 0 semupl 112 2 0 2 1 1 0 1 0 8 0 semapl 112 687 0 677 1 0 1 1 0 8 0 shmpl 112 139 0 11 4 0 4 4 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 6570 0 5159 46 0 46 46 0 8 0 ffsino 272 6570 0 5159 95 0 95 95 0 8 0 nchpl 144 11733 0 11272 61 40 21 61 0 8 0 uvmvnodes 72 6289 0 0 115 0 115 115 0 8 0 vnodes 208 6289 0 0 331 0 331 331 0 8 0 namei 1024 41015 0 41015 7 6 1 1 0 8 1 percpumem 16 30 0 0 1 0 1 1 0 8 0 vcpupl 1984 19 0 0 3 0 3 3 0 8 0 vmpool 552 40 0 21 4 2 2 2 0 8 0 scsiplug 64 9 0 9 5 5 0 1 0 8 0 scxspl 192 37677 0 37677 33 30 3 7 0 8 3 plimitpl 152 293 0 285 1 0 1 1 0 8 0 sigapl 432 3504 0 3488 3 1 2 3 0 8 0 futexpl 56 72577 0 72575 4 3 1 1 0 8 0 knotepl 112 892 0 873 4 3 1 3 0 8 0 kqueuepl 104 910 0 907 1 0 1 1 0 8 0 pipepl 112 3816 0 3792 15 13 2 3 0 8 1 fdescpl 488 3505 0 3488 3 0 3 3 0 8 0 filepl 152 31831 0 31721 33 27 6 14 0 8 1 lockfpl 104 1160 0 1157 1 0 1 1 0 8 0 lockfspl 48 388 0 386 1 0 1 1 0 8 0 sessionpl 112 37 0 26 1 0 1 1 0 8 0 pgrppl 48 74 0 63 1 0 1 1 0 8 0 ucredpl 96 3410 0 3401 1 0 1 1 0 8 0 zombiepl 144 3490 0 3490 8 7 1 1 0 8 1 processpl 896 3524 0 3490 4 0 4 4 0 8 0 procpl 632 11147 0 11100 7 2 5 5 0 8 0 srpgc 64 28 0 28 11 10 1 1 0 8 1 sosppl 128 56 0 56 12 11 1 1 0 8 1 sockpl 384 11515 0 11490 48 43 5 22 0 8 2 mcl64k 65536 282 0 0 35 3 32 35 0 8 1 mcl16k 16384 9 0 0 2 0 2 2 0 8 0 mcl12k 12288 17 0 0 2 0 2 2 0 8 0 mcl9k 9216 12 0 0 1 0 1 1 0 8 0 mcl8k 8192 17 0 0 3 0 3 3 0 8 0 mcl4k 4096 17 0 0 3 0 3 3 0 8 0 mcl2k2 2112 9 0 0 1 0 1 1 0 8 0 mcl2k 2048 204 0 0 24 2 22 24 0 8 0 mtagpl 80 53 0 0 1 0 1 1 0 8 0 mbufpl 256 594 0 0 22 0 22 22 0 8 0 bufpl 256 20574 0 13526 441 0 441 441 0 8 0 anonpl 16 420390 0 402886 171 81 90 91 0 124 16 amapchunkpl 152 24064 0 23914 50 43 7 14 0 158 0 amappl16 192 20051 0 18993 174 114 60 65 0 8 7 amappl15 184 853 0 849 2 1 1 1 0 8 0 amappl14 176 383 0 379 2 1 1 1 0 8 0 amappl13 168 804 0 803 1 0 1 1 0 8 0 amappl12 160 19 0 19 4 4 0 1 0 8 0 amappl11 152 254 0 239 1 0 1 1 0 8 0 amappl10 144 164 0 160 1 0 1 1 0 8 0 amappl9 136 1679 0 1672 1 0 1 1 0 8 0 amappl8 128 1203 0 1169 2 0 2 2 0 8 0 amappl7 120 260 0 251 1 0 1 1 0 8 0 amappl6 112 242 0 232 1 0 1 1 0 8 0 amappl5 104 285 0 271 1 0 1 1 0 8 0 amappl4 96 4558 0 4521 1 0 1 1 0 8 0 amappl3 88 349 0 341 1 0 1 1 0 8 0 amappl2 80 26631 0 26547 3 1 2 3 0 8 0 amappl1 72 88600 0 88137 25 15 10 20 0 8 0 amappl 80 11709 0 11648 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 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 17 0 17 1 1 0 1 0 8 0 aobjpl 64 140 0 11 3 0 3 3 0 8 0 uaddrrnd 24 3545 0 3488 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 3545 0 3488 1 0 1 1 0 8 0 vmmpekpl 168 34949 0 34907 3 0 3 3 0 8 0 vmmpepl 168 450080 0 447712 306 169 137 141 0 357 33 vmsppl 368 3504 0 3488 2 0 2 2 0 8 0 pdppl 4096 7097 0 7037 12 4 8 8 0 8 0 pvpl 32 1117831 0 1096768 344 136 208 209 0 265 34 pmappl 232 3544 0 3509 6 3 3 3 0 8 0 extentpl 40 41 0 26 1 0 1 1 0 8 0 phpool 112 683 0 33 19 0 19 19 0 8 0