panic: pool_p_free: pffrnode free list modified: page 0xfffffd80656c9000; item addr 0xfffffd80656c9000; offset 0x0=0x0 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 410197 56933 0 0x2 0x4000080 0 syz-fuzzer *358675 51860 0 0x14000 0x200 1 systqmp db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff82226e7f) at panic+0x15c sys/kern/subr_prf.c:207 pool_p_free(ffffffff82650350,fffffd80656c9f90) at pool_p_free+0x1de sys/kern/subr_pool.c:991 pool_gc_pages(0) at pool_gc_pages+0x255 sys/kern/subr_pool.c:1586 taskq_thread(ffffffff8249bb80) at taskq_thread+0x9c sys/kern/kern_task.c:369 end trace frame: 0x0, count: 10 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_p_free: pffrnode free list modified: page 0xfffffd80656c9000; item addr 0xfffffd80656c9000; offset 0x0=0x0 ddb{1}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff82226e7f) at panic+0x15c sys/kern/subr_prf.c:207 pool_p_free(ffffffff82650350,fffffd80656c9f90) at pool_p_free+0x1de sys/kern/subr_pool.c:991 pool_gc_pages(0) at pool_gc_pages+0x255 sys/kern/subr_pool.c:1586 taskq_thread(ffffffff8249bb80) at taskq_thread+0x9c sys/kern/kern_task.c:369 end trace frame: 0x0, count: -5 ddb{1}> show registers rdi 0 rsi 0x1 rbp 0xffff800020a40d70 rbx 0xffff800020a40e20 rdx 0xffff800020a204f0 rcx 0 rax 0 r8 0xffffffff81208dbf kprintf+0x16f r9 0x1 r10 0x25 r11 0x716fd71e616d6414 r12 0x3000000008 r13 0xffff800020a40d80 r14 0x100 r15 0x1 rip 0xffffffff81d4f1f8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800020a40d60 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{1}> show proc PROC (systqmp) pid=358675 stat=onproc flags process=14000 proc=200 pri=32, usrpri=51, nice=20 forw=0xffffffffffffffff, list=0xffff800020a20768,0xffff800020a20010 process=0xffff800020a22710 user=0xffff800020a3c000, vmspace=0xffffffff826157f0 estcpu=1, cpticks=1, pctcpu=0.0 user=0, sys=1, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 34810 95863 82456 0 2 0x480 syz-executor.1 34810 456786 82456 0 3 0x4000080 kqread syz-executor.1 34810 523240 82456 0 3 0x4000080 fsleep syz-executor.1 82456 48704 56933 0 3 0x82 nanosleep syz-executor.1 4134 511907 0 0 3 0x14200 bored sosplice 84205 123865 56933 0 2 0x2 syz-executor.0 56933 229387 3535 0 3 0x82 thrsleep syz-fuzzer 56933 272772 3535 0 3 0x4000082 thrsleep syz-fuzzer 56933 44646 3535 0 3 0x4000082 thrsleep syz-fuzzer 56933 460756 3535 0 3 0x4000082 thrsleep syz-fuzzer 56933 1186 3535 0 3 0x4000082 thrsleep syz-fuzzer 56933 233052 3535 0 3 0x4000082 thrsleep syz-fuzzer 56933 175639 3535 0 3 0x4000082 thrsleep syz-fuzzer 56933 380518 3535 0 3 0x4000082 thrsleep syz-fuzzer 56933 243986 3535 0 3 0x4000082 thrsleep syz-fuzzer 56933 410197 3535 0 7 0x4000082 syz-fuzzer 3535 441273 94678 0 3 0x10008a pause ksh 94678 206694 36014 0 3 0x92 select sshd 3125 26738 1 0 3 0x100083 ttyin getty 36014 405053 1 0 3 0x80 select sshd 31359 430353 95839 74 3 0x100092 bpf pflogd 95839 389014 1 0 3 0x80 netio pflogd 2364 49432 47303 73 3 0x100090 kqread syslogd 47303 423067 1 0 3 0x100082 netio syslogd 72544 492532 1 77 3 0x100090 poll dhclient 93472 348799 1 0 3 0x80 poll dhclient 68264 255404 0 0 3 0x14200 pgzero zerothread 59871 175847 0 0 3 0x14200 aiodoned aiodoned 34061 271726 0 0 3 0x14200 syncer update 91140 461037 0 0 3 0x14200 cleaner cleaner 50444 104493 0 0 3 0x14200 reaper reaper 87240 347908 0 0 3 0x14200 pgdaemon pagedaemon 98952 283119 0 0 3 0x14200 bored crynlk 26186 176177 0 0 3 0x14200 bored crypto 5109 19813 0 0 3 0x40014200 acpi0 acpi0 95500 447174 0 0 3 0x40014200 idle1 31629 99634 0 0 3 0x14200 bored softnet *51860 358675 0 0 7 0x14200 systqmp 18426 504477 0 0 3 0x14200 bored systq 58077 306699 0 0 3 0x40014200 bored softclock 41582 322061 0 0 3 0x40014200 idle0 82434 360152 0 0 3 0x14200 bored smr 1 489638 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks CPU 0: exclusive sched_lock &sched_lock r = 0 (0xffffffff8265d420) #0 witness_lock+0x52e sys/kern/subr_witness.c:1163 #1 sleep_setup+0xe9 sys/kern/kern_synch.c:366 #2 tsleep+0xe6 sleep_setup_timeout sys/kern/kern_synch.c:405 [inline] #2 tsleep+0xe6 sys/kern/kern_synch.c:149 #3 sys_nanosleep+0x1b8 sys/kern/kern_time.c:296 #4 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:92 [inline] #4 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:555 #5 Xsyscall+0x128 Process 82456 (syz-executor.1) thread 0xffff800020ac0290 (48704) exclusive kernel_lock &kernel_lock r = 1 (0xffffffff82642030) #0 witness_lock+0x52e sys/kern/subr_witness.c:1163 #1 syscall+0x400 mi_syscall sys/sys/syscall_mi.h:83 [inline] #1 syscall+0x400 sys/arch/amd64/amd64/trap.c:555 #2 Xsyscall+0x128 Process 51860 (systqmp) thread 0xffff800020a204f0 (358675) shared rwlock pools r = 0 (0xffffffff824ee980) #0 witness_lock+0x52e sys/kern/subr_witness.c:1163 #1 pool_gc_pages+0x21 sys/kern/subr_pool.c:1563 #2 taskq_thread+0x9c sys/kern/kern_task.c:369 #3 proc_trampoline+0x1c shared rwlock systqmp r = 0 (0xffffffff8249bbe0) #0 witness_lock+0x52e sys/kern/subr_witness.c:1163 #1 taskq_thread+0x8f sys/kern/kern_task.c:368 #2 proc_trampoline+0x1c ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 9539 7059K 8547K 78643K 13164 0 pcb 13 8K 8K 78643K 249 0 rtable 104 3K 4K 78643K 478 0 ifaddr 81 15K 16K 78643K 188 0 counters 39 33K 33K 78643K 39 0 ioctlops 0 0K 4K 78643K 1499 0 iov 0 0K 16K 78643K 145 0 mount 1 1K 1K 78643K 1 0 vnodes 1221 77K 77K 78643K 1926 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 7 0 VM map 2 1K 1K 78643K 2 0 sem 12 0K 1K 78643K 219 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 196K 290K 78643K 12766 0 file desc 5 13K 25K 78643K 489 0 sigio 0 0K 0K 78643K 16 0 proc 61 63K 95K 78643K 527 0 subproc 32 2K 2K 78643K 51 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 37 0 in_multi 55 3K 3K 78643K 100 0 ether_multi 1 0K 0K 78643K 6 0 mrt 0 0K 0K 78643K 6 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 78 344K 344K 78643K 78 0 exec 0 0K 1K 78643K 278 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 130 71K 72K 78643K 2629 0 UVM aobj 39 7K 7K 78643K 41 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 122 0 NDP 14 0K 0K 78643K 43 0 temp 144 3035K 3670K 78643K 6865 0 kqueue 0 0K 0K 78643K 2 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 11 0 5 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtpcb 80 105 0 103 1 0 1 1 0 8 0 rtentry 112 81 0 39 2 0 2 2 0 8 0 unpcb 120 312 0 302 1 0 1 1 0 8 0 syncache 264 6 0 6 2 1 1 1 0 8 1 tcpqe 32 559 0 559 1 1 0 1 0 8 0 tcpcb 544 249 0 245 2 1 1 2 0 8 0 inpcb 280 868 0 859 2 0 2 2 0 8 1 rttmr 72 2 0 2 1 1 0 1 0 8 0 nd6 48 10 0 7 1 0 1 1 0 8 0 pkpcb 40 2 0 2 1 1 0 1 0 8 0 ppxss 1128 9 0 9 1 1 0 1 0 8 0 pffrag 232 15 0 15 1 1 0 1 0 482 0 pffrnode 88 15 0 15 1 1 0 1 0 8 0 pffrent 40 419 0 419 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 48 0 12 1 0 1 1 0 8 0 pfstkey 112 48 0 12 2 0 2 2 0 8 0 pfstate 328 48 0 12 4 0 4 4 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 256 369 0 164 15 0 15 15 0 8 0 art_table 32 370 0 164 2 0 2 2 0 8 0 art_node 16 80 0 41 1 0 1 1 0 8 0 sysvmsgpl 40 20 0 10 1 0 1 1 0 8 0 semupl 112 2 0 2 1 1 0 1 0 8 0 semapl 112 207 0 197 1 0 1 1 0 8 0 shmpl 112 39 0 2 2 0 2 2 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 2153 0 752 46 0 46 46 0 8 0 ffsino 272 2153 0 752 95 0 95 95 0 8 0 nchpl 144 3059 0 1445 61 0 61 61 0 8 0 uvmvnodes 72 2792 0 0 51 0 51 51 0 8 0 vnodes 208 2792 0 0 147 0 147 147 0 8 0 namei 1024 9535 0 9535 1 0 1 1 0 8 1 percpumem 16 30 0 0 1 0 1 1 0 8 0 vcpupl 1984 6 0 0 1 0 1 1 0 8 0 vmpool 560 10 0 4 1 0 1 1 0 8 0 scsiplug 64 2 0 2 2 2 0 1 0 8 0 scxspl 192 9169 0 9169 8 7 1 7 0 8 1 plimitpl 152 54 0 46 1 0 1 1 0 8 0 sigapl 432 685 0 670 3 1 2 3 0 8 0 futexpl 56 10953 0 10952 1 0 1 1 0 8 0 knotepl 112 141 0 122 1 0 1 1 0 8 0 kqueuepl 104 117 0 114 1 0 1 1 0 8 0 pipepl 160 450 0 431 2 0 2 2 0 8 1 fdescpl 488 686 0 670 3 0 3 3 0 8 0 filepl 152 5564 0 5457 6 1 5 6 0 8 0 lockfpl 104 145 0 143 1 0 1 1 0 8 0 lockfspl 48 50 0 48 1 0 1 1 0 8 0 sessionpl 112 19 0 8 1 0 1 1 0 8 0 pgrppl 48 21 0 10 1 0 1 1 0 8 0 ucredpl 96 589 0 580 1 0 1 1 0 8 0 zombiepl 144 670 0 670 1 0 1 1 0 8 1 processpl 904 702 0 670 4 0 4 4 0 8 0 procpl 632 1769 0 1726 5 0 5 5 0 8 1 srpgc 64 1 0 1 1 1 0 1 0 8 0 sosppl 128 4 0 4 2 2 0 1 0 8 0 sockpl 384 1306 0 1285 6 2 4 5 0 8 1 mcl64k 65536 19 0 0 3 0 3 3 0 8 0 mcl16k 16384 3 0 0 1 0 1 1 0 8 0 mcl12k 12288 5 0 0 1 0 1 1 0 8 0 mcl9k 9216 3 0 0 1 0 1 1 0 8 0 mcl8k 8192 10 0 0 2 0 2 2 0 8 0 mcl4k 4096 16 0 0 2 0 2 2 0 8 0 mcl2k2 2112 3 0 0 1 0 1 1 0 8 0 mcl2k 2048 174 0 0 21 0 21 21 0 8 0 mtagpl 80 20 0 0 1 0 1 1 0 8 0 mbufpl 256 400 0 0 23 0 23 23 0 8 0 bufpl 280 7632 0 1352 449 0 449 449 0 8 0 anonpl 16 100546 0 80554 101 4 97 97 0 125 13 amapchunkpl 152 5151 0 4992 16 4 12 13 0 158 3 amappl16 192 3384 0 2293 68 5 63 67 0 8 8 amappl15 184 318 0 311 1 0 1 1 0 8 0 amappl14 176 344 0 342 1 0 1 1 0 8 0 amappl13 168 1 0 0 1 0 1 1 0 8 0 amappl12 160 7 0 4 1 0 1 1 0 8 0 amappl11 152 58 0 43 1 0 1 1 0 8 0 amappl10 144 11 0 7 1 0 1 1 0 8 0 amappl9 136 615 0 612 1 0 1 1 0 8 0 amappl8 128 164 0 132 2 0 2 2 0 8 0 amappl7 120 108 0 97 1 0 1 1 0 8 0 amappl6 112 58 0 51 1 0 1 1 0 8 0 amappl5 104 144 0 128 1 0 1 1 0 8 0 amappl4 96 860 0 826 1 0 1 1 0 8 0 amappl3 88 520 0 513 1 0 1 1 0 8 0 amappl2 80 4661 0 4582 3 1 2 3 0 8 0 amappl1 72 24988 0 24528 26 16 10 21 0 8 0 amappl 80 2060 0 2010 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 40 0 2 1 0 1 1 0 8 0 uaddrrnd 24 696 0 674 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 696 0 674 1 0 1 1 0 8 0 vmmpekpl 168 8478 0 8442 2 0 2 2 0 8 0 vmmpepl 168 92227 0 89923 158 28 130 140 0 357 24 vmsppl 368 695 0 674 3 0 3 3 0 8 1 pdppl 4096 1399 0 1354 7 0 7 7 0 8 1 pvpl 32 277329 0 254132 232 6 226 226 0 265 34 pmappl 232 695 0 674 3 1 2 2 0 8 0 extentpl 40 46 0 29 1 0 1 1 0 8 0 phpool 112 187 0 4 6 0 6 6 0 8 0