panic(ffffffff821f20dc) at panic+0x15c sys/kern/subr_prf.c:207 pool_cache_get(ffffffff826845d0) at pool_cache_get+0x323 pool_cache_item_magic_check sys/kern/subr_pool.c:1781 [inline] pool_cache_get(ffffffff826845d0) at pool_cache_get+0x323 sys/kern/subr_pool.c:1884 pool_get(ffffffff826845d0,2) at pool_get+0x91 sys/kern/subr_pool.c:572 m_gethdr(2,2) at m_gethdr+0x4c sys/kern/uipc_mbuf.c:283 tcp_output(ffff800000a0a440) at tcp_output+0x14e6 tcp_usrreq(fffffd806eb5a648,9,fffffd80644bad00,0,0,ffff800020ade280) at tcp_usrreq+0xa55 sosend(fffffd806eb5a648,0,ffff800020acfcc8,0,0,80) at sosend+0x671 sys/kern/uipc_socket.c:549 dofilewritev(ffff800020ade280,4,ffff800020acfcc8,0,ffff800020acfdb0) at dofilewritev+0x1b6 sys/kern/sys_generic.c:365 sys_write(ffff800020ade280,ffff800020acfd60,ffff800020acfdb0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff800020acfe30) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff800020acfe30) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe6eb0, count: 3 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 0xfffffd80644bae00+16 0x0!=0xf9b62a37acb3b6ed ddb{1}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821f20dc) at panic+0x15c sys/kern/subr_prf.c:207 pool_cache_get(ffffffff826845d0) at pool_cache_get+0x323 pool_cache_item_magic_check sys/kern/subr_pool.c:1781 [inline] pool_cache_get(ffffffff826845d0) at pool_cache_get+0x323 sys/kern/subr_pool.c:1884 pool_get(ffffffff826845d0,2) at pool_get+0x91 sys/kern/subr_pool.c:572 m_gethdr(2,2) at m_gethdr+0x4c sys/kern/uipc_mbuf.c:283 tcp_output(ffff800000a0a440) at tcp_output+0x14e6 tcp_usrreq(fffffd806eb5a648,9,fffffd80644bad00,0,0,ffff800020ade280) at tcp_usrreq+0xa55 sosend(fffffd806eb5a648,0,ffff800020acfcc8,0,0,80) at sosend+0x671 sys/kern/uipc_socket.c:549 dofilewritev(ffff800020ade280,4,ffff800020acfcc8,0,ffff800020acfdb0) at dofilewritev+0x1b6 sys/kern/sys_generic.c:365 sys_write(ffff800020ade280,ffff800020acfd60,ffff800020acfdb0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff800020acfe30) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff800020acfe30) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe6eb0, count: -12 ddb{1}> show registers rdi 0 rsi 0x1 rbp 0xffff800020acf6c0 rbx 0xffff800020acf770 rdx 0xffff800020ade280 rcx 0 rax 0 r8 0xffffffff818f472f kprintf+0x16f r9 0x1 r10 0x25 r11 0x492800d8afa21892 r12 0x3000000008 r13 0xffff800020acf6d0 r14 0x100 r15 0x1 rip 0xffffffff818a9a48 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800020acf6b0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{1}> show proc PROC (sshd) pid=497303 stat=onproc flags process=12 proc=0 pri=50, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff800020ade4f0,0xffff800020adec50 process=0xffff800020ac9350 user=0xffff800020aca000, vmspace=0xfffffd806e98b2e8 estcpu=0, cpticks=2, pctcpu=0.1 user=0, sys=2, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 87452 415133 19834 0 2 0 syz-executor.1 87452 346907 19834 0 3 0x4000080 fsleep syz-executor.1 87452 429785 19834 0 7 0x4000000 syz-executor.1 44310 217957 0 0 3 0x14200 bored sosplice 19834 237164 83006 0 2 0x482 syz-executor.1 68879 406756 83006 0 2 0x2 syz-executor.0 83006 73926 99709 0 3 0x82 thrsleep syz-fuzzer 83006 397856 99709 0 2 0x4000482 syz-fuzzer 83006 347177 99709 0 3 0x4000082 thrsleep syz-fuzzer 83006 459191 99709 0 3 0x4000082 kqread syz-fuzzer 83006 186517 99709 0 3 0x4000082 thrsleep syz-fuzzer 83006 263334 99709 0 3 0x4000082 thrsleep syz-fuzzer 83006 504123 99709 0 3 0x4000082 thrsleep syz-fuzzer 83006 413279 99709 0 2 0x4000482 syz-fuzzer 83006 263455 99709 0 3 0x4000082 thrsleep syz-fuzzer 83006 195838 99709 0 3 0x4000082 thrsleep syz-fuzzer 83006 87980 99709 0 3 0x4000082 thrsleep syz-fuzzer 99709 293704 57317 0 3 0x10008a pause ksh *57317 497303 41172 0 7 0x12 sshd 71854 339958 1 0 3 0x100083 ttyin getty 41172 23618 1 0 3 0x80 select sshd 84232 68565 85701 74 3 0x100092 bpf pflogd 85701 345346 1 0 3 0x80 netio pflogd 4521 328027 99249 73 3 0x100090 kqread syslogd 99249 19408 1 0 3 0x100082 netio syslogd 36394 326746 1 77 3 0x100090 poll dhclient 11913 110014 1 0 3 0x80 poll dhclient 82665 404240 0 0 3 0x14200 bored smr 25640 352983 0 0 2 0x14200 zerothread 47287 109707 0 0 3 0x14200 aiodoned aiodoned 81034 457835 0 0 3 0x14200 syncer update 39511 471510 0 0 3 0x14200 cleaner cleaner 15859 468783 0 0 3 0x14200 reaper reaper 54021 98812 0 0 3 0x14200 pgdaemon pagedaemon 1176 285848 0 0 3 0x14200 bored crynlk 10989 427677 0 0 3 0x14200 bored crypto 67467 199221 0 0 3 0x40014200 acpi0 acpi0 36541 183479 0 0 3 0x40014200 idle1 14356 64506 0 0 3 0x14200 bored softnet 36106 445232 0 0 3 0x14200 bored systqmp 65379 58400 0 0 3 0x14200 bored systq 75980 515900 0 0 3 0x40014200 bored softclock 17379 41979 0 0 3 0x40014200 idle0 1 5567 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks Process 68879 (syz-executor.0) thread 0xffff800020a6dd48 (406756) exclusive rrwlock inode r = 0 (0xfffffd806b424808) #0 witness_lock+0x4c5 sys/kern/subr_witness.c:1164 #1 rw_enter+0x453 sys/kern/kern_rwlock.c:311 #2 rrw_enter+0x88 sys/kern/kern_rwlock.c:462 #3 ufs_ihashins+0x45 sys/ufs/ufs/ufs_ihash.c:140 #4 ffs_vget+0x13e sys/ufs/ffs/ffs_vfsops.c:1358 #5 ffs_inode_alloc+0x1cf sys/ufs/ffs/ffs_alloc.c:392 #6 ufs_mkdir+0xf4 sys/ufs/ufs/ufs_vnops.c:1162 #7 VOP_MKDIR+0xc6 sys/kern/vfs_vops.c:449 #8 domkdirat+0x121 sys/kern/vfs_syscalls.c:3058 #9 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline] #9 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570 #10 Xsyscall+0x128 exclusive rrwlock inode r = 0 (0xfffffd806b424098) #0 witness_lock+0x4c5 sys/kern/subr_witness.c:1164 #1 rw_enter+0x453 sys/kern/kern_rwlock.c:311 #2 rrw_enter+0x88 sys/kern/kern_rwlock.c:462 #3 VOP_LOCK+0x4b sys/kern/vfs_vops.c:602 #4 vn_lock+0x81 sys/kern/vfs_vnops.c:575 #5 vfs_lookup+0xe6 sys/kern/vfs_lookup.c:419 #6 namei+0x63c sys/kern/vfs_lookup.c:249 #7 domkdirat+0x75 sys/kern/vfs_syscalls.c:3043 #8 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline] #8 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570 #9 Xsyscall+0x128 Process 83006 (syz-fuzzer) thread 0xffff800020adfd50 (186517) exclusive kernel_lock &kernel_lock r = 0 (0xffffffff82676570) #0 witness_lock+0x4c5 sys/kern/subr_witness.c:1164 #1 sleep_setup+0xc7 sys/kern/kern_synch.c:388 #2 rwsleep+0x81 sleep_setup_timeout sys/kern/kern_synch.c:434 [inline] #2 rwsleep+0x81 sys/kern/kern_synch.c:323 #3 thrsleep+0x3eb sys/kern/kern_synch.c:729 #4 sys___thrsleep+0xb5 sys/kern/kern_synch.c:770 #5 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline] #5 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570 #6 Xsyscall+0x128 exclusive rwlock pslock r = 0 (0xffff800020ac80f8) #0 witness_lock+0x4c5 sys/kern/subr_witness.c:1164 #1 thrsleep+0x364 sys/kern/kern_synch.c:722 #2 sys___thrsleep+0xb5 sys/kern/kern_synch.c:770 #3 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline] #3 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570 #4 Xsyscall+0x128 Process 57317 (sshd) thread 0xffff800020ade280 (497303) exclusive rwlock netlock r = 0 (0xffffffff82526378) #0 witness_lock+0x4c5 sys/kern/subr_witness.c:1164 #1 solock+0x5a sys/kern/uipc_socket2.c:282 #2 sosend+0x559 sys/kern/uipc_socket.c:537 #3 dofilewritev+0x1b6 sys/kern/sys_generic.c:365 #4 sys_write+0x83 sys/kern/sys_generic.c:285 #5 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline] #5 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570 #6 Xsyscall+0x128 ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 9500 6472K 6794K 78643K 10690 0 pcb 13 8K 8K 78643K 23 0 rtable 105 3K 3K 78643K 222 0 ifaddr 61 13K 13K 78643K 74 0 counters 43 33K 34K 78643K 47 0 ioctlops 0 0K 4K 78643K 1469 0 iov 0 0K 16K 78643K 10 0 mount 1 1K 1K 78643K 1 0 vnodes 1222 77K 77K 78643K 1253 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 1K 78643K 2 0 VM map 2 1K 1K 78643K 2 0 sem 7 0K 0K 78643K 7 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 196K 290K 78643K 12766 0 file desc 5 13K 25K 78643K 67 0 proc 60 63K 83K 78643K 439 0 subproc 32 2K 2K 78643K 34 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 in_multi 47 2K 2K 78643K 47 0 ether_multi 1 0K 0K 78643K 1 0 mrt 0 0K 0K 78643K 2 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 43 201K 201K 78643K 43 0 exec 0 0K 1K 78643K 219 0 pagedep 1 8K 8K 78643K 1 0 inodedep 1 32K 32K 78643K 1 0 newblk 1 0K 0K 78643K 1 0 VM swap 7 26K 26K 78643K 7 0 UVM amap 96 21K 25K 78643K 1107 0 UVM aobj 2 2K 2K 78643K 2 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 2 0 NDP 9 0K 0K 78643K 15 0 temp 83 3037K 3101K 78643K 2166 0 kqueue 3 4K 4K 78643K 3 0 SYN cache 2 16K 16K 78643K 2 0 ddb{1}> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle arp 64 6 0 0 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtpcb 80 21 0 19 1 0 1 1 0 8 0 rtentry 112 46 0 2 2 0 2 2 0 8 0 unpcb 120 37 0 27 1 0 1 1 0 8 0 syncache 264 4 0 4 1 1 0 1 0 8 0 tcpqe 32 31 0 31 1 0 1 1 0 8 1 tcpcb 544 24 0 20 1 0 1 1 0 8 0 inpcb 280 107 0 98 2 0 2 2 0 8 1 rttmr 72 1 0 1 1 0 1 1 0 8 1 nd6 48 6 0 0 1 0 1 1 0 8 0 pffrag 232 1 0 1 1 0 1 1 0 482 1 pffrnode 88 1 0 1 1 0 1 1 0 8 1 pffrent 40 47 0 47 1 0 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 16 0 0 1 0 1 1 0 8 0 pfstkey 112 16 0 0 1 0 1 1 0 8 0 pfstate 328 16 0 0 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 256 189 0 0 12 0 12 12 0 8 0 art_table 32 190 0 0 2 0 2 2 0 8 0 art_node 16 45 0 5 1 0 1 1 0 8 0 semapl 112 5 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 1475 0 68 46 0 46 46 0 8 0 ffsino 272 1475 0 68 94 0 94 94 0 8 0 nchpl 144 1744 0 129 61 0 61 61 0 8 0 uvmvnodes 72 1541 0 0 29 0 29 29 0 8 0 vnodes 208 1541 0 0 82 0 82 82 0 8 0 namei 1024 4510 0 4509 1 0 1 1 0 8 0 percpumem 16 34 0 2 1 0 1 1 0 8 0 scxspl 192 5210 0 5210 7 1 6 6 0 8 6 plimitpl 152 19 0 11 1 0 1 1 0 8 0 sigapl 424 283 0 251 4 0 4 4 0 8 0 futexpl 56 671 0 670 1 0 1 1 0 8 0 knotepl 112 53 0 34 1 0 1 1 0 8 0 kqueuepl 144 12 0 10 1 0 1 1 0 8 0 pipelkpl 48 82 0 72 1 0 1 1 0 8 0 pipepl 120 164 0 145 1 0 1 1 0 8 0 fdescpl 496 267 0 251 3 0 3 3 0 8 0 filepl 152 1389 0 1287 5 0 5 5 0 8 1 lockfpl 104 10 0 9 1 0 1 1 0 8 0 lockfspl 48 5 0 4 1 0 1 1 0 8 0 sessionpl 112 18 0 7 1 0 1 1 0 8 0 pgrppl 48 18 0 7 1 0 1 1 0 8 0 ucredpl 96 95 0 86 1 0 1 1 0 8 0 zombiepl 144 251 0 251 1 0 1 1 0 8 1 processpl 984 283 0 251 5 0 5 5 0 8 0 procpl 624 368 0 324 4 0 4 4 0 8 0 sockpl 400 165 0 144 4 0 4 4 0 8 1 mcl64k 65536 4 0 0 1 0 1 1 0 8 0 mcl12k 12288 1 0 0 1 0 1 1 0 8 0 mcl4k 4096 3 0 0 1 0 1 1 0 8 0 mcl2k 2048 157 0 0 19 0 19 19 0 8 0 mtagpl 80 12 0 0 1 0 1 1 0 8 0 mbufpl 256 240 0 0 15 0 15 15 0 8 0 bufpl 280 4094 0 174 280 0 280 280 0 8 0 anonpl 16 38836 0 25051 59 1 58 58 0 124 1 amapchunkpl 152 1321 0 1189 8 0 8 8 0 158 0 amappl16 192 983 0 241 38 0 38 38 0 8 0 amappl15 184 34 0 31 1 0 1 1 0 8 0 amappl14 176 2 0 2 2 2 0 1 0 8 0 amappl13 168 26 0 24 1 0 1 1 0 8 0 amappl12 160 24 0 21 1 0 1 1 0 8 0 amappl11 152 76 0 57 1 0 1 1 0 8 0 amappl10 144 15 0 10 1 0 1 1 0 8 0 amappl9 136 383 0 379 1 0 1 1 0 8 0 amappl8 128 300 0 287 1 0 1 1 0 8 0 amappl7 120 118 0 108 1 0 1 1 0 8 0 amappl6 112 23 0 21 1 0 1 1 0 8 0 amappl5 104 196 0 178 1 0 1 1 0 8 0 amappl4 96 499 0 470 1 0 1 1 0 8 0 amappl3 88 103 0 98 1 0 1 1 0 8 0 amappl2 80 1207 0 1138 3 0 3 3 0 8 1 amappl1 72 15910 0 15461 25 9 16 20 0 8 6 amappl 80 615 0 571 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 18 0 17 1 0 1 1 0 8 0 aobjpl 64 1 0 0 1 0 1 1 0 8 0 uaddrrnd 24 267 0 251 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 267 0 251 1 0 1 1 0 8 0 vmmpekpl 168 6035 0 6007 2 0 2 2 0 8 0 vmmpepl 168 39691 0 37815 106 3 103 103 0 357 21 vmsppl 368 266 0 251 2 0 2 2 0 8 0 pdppl 4096 542 0 502 6 0 6 6 0 8 0 pvpl 32 139230 0 122314 145 0 145 145 0 265 6 pmappl 232 266 0 251 2 0 2 2 0 8 1 extentpl 40 46 0 29 1 0 1 1 0 8 0 phpool 112 168 0 3 5 0 5 5 0 8 0