panic: pool_cache_iWtAeRmNI_mNG: agSPiLc _cNhOeTc kL:O WmEbREuDf pOlN c SpYu SCfreALeL l 1i3s7t -m20o4d0i8fi0 eEdX: ITi te0m a a ddStopped at savectx+0xb1: movl $0,%gs:0x530 TID PID UID PRFLAGS PFLAGS CPU COMMAND *177406 85634 0 0x2 0 0 syz-executor.0 355344 22017 0 0x14000 0x200 1 softnet savectx() at savectx+0xb1 end of kernel end trace frame: 0x7f7ffffce2c0, count: 14 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 pool_cache_item_magic_check: mbufpl cpu free list modified: item addr 0xfffffd8066c10c00+16 0x0!=0x30a60d49b0f94d9f ddb{0}> trace savectx() at savectx+0xb1 end of kernel end trace frame: 0x7f7ffffce2c0, count: -1 ddb{0}> show registers rdi 0 rsi 0 rbp 0xffff800023db5540 rbx 0 rdx 0xffff800020ae6c48 rcx 0 rax 0x39 r8 0xffffffff81b1c10f kprintf+0x16f r9 0x1 r10 0x25 r11 0x6d34dbcf995ed645 r12 0 r13 0 r14 0xffff800020ae6c48 r15 0 rip 0xffffffff81e903f1 savectx+0xb1 cs 0x8 rflags 0x46 rsp 0xffff800023db54c0 ss 0x10 savectx+0xb1: movl $0,%gs:0x530 ddb{0}> show proc PROC (syz-executor.0) pid=177406 stat=onproc flags process=2 proc=0 pri=77, usrpri=77, nice=20 forw=0xffffffffffffffff, list=0xffff800020a7dad8,0xffff800020ae7888 process=0xffff800020a912d0 user=0xffff800023db0000, vmspace=0xfffffd807f000b80 estcpu=36, cpticks=1, pctcpu=0.2 user=0, sys=1, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 29541 115109 0 0 3 0x14200 bored sosplice *85634 177406 10768 0 7 0x2 syz-executor.0 96194 139440 10768 0 2 0x2 syz-executor.1 10768 253670 87985 0 3 0x82 thrsleep syz-fuzzer 10768 118680 87985 0 3 0x4000082 nanosleep syz-fuzzer 10768 516155 87985 0 3 0x4000082 thrsleep syz-fuzzer 10768 259909 87985 0 3 0x4000082 thrsleep syz-fuzzer 10768 129716 87985 0 3 0x4000082 nanosleep syz-fuzzer 10768 70965 87985 0 3 0x4000082 thrsleep syz-fuzzer 10768 479852 87985 0 3 0x4000082 thrsleep syz-fuzzer 10768 340492 87985 0 3 0x4000082 thrsleep syz-fuzzer 10768 43576 87985 0 3 0x4000082 thrsleep syz-fuzzer 10768 173479 87985 0 3 0x4000082 kqread syz-fuzzer 87985 409312 4990 0 3 0x10008a pause ksh 4990 96441 62655 0 3 0x92 select sshd 66005 287683 1 0 3 0x100083 ttyin getty 62655 116376 1 0 3 0x80 select sshd 76145 149617 2472 74 3 0x100092 bpf pflogd 2472 301165 1 0 3 0x80 netio pflogd 6838 218603 29761 73 3 0x100090 kqread syslogd 29761 221923 1 0 3 0x100082 netio syslogd 30859 366408 1 77 3 0x100090 poll dhclient 11471 9978 1 0 3 0x80 poll dhclient 59828 267992 0 0 2 0x14200 zerothread 66346 503067 0 0 3 0x14200 aiodoned aiodoned 36492 408448 0 0 3 0x14200 syncer update 79570 44509 0 0 3 0x14200 cleaner cleaner 85115 129741 0 0 3 0x14200 reaper reaper 72626 437775 0 0 3 0x14200 pgdaemon pagedaemon 27369 241727 0 0 3 0x14200 bored crynlk 63997 71238 0 0 3 0x14200 bored crypto 67852 517628 0 0 3 0x40014200 acpi0 acpi0 64425 422527 0 0 3 0x40014200 idle1 22017 355344 0 0 7 0x14200 softnet 98419 406601 0 0 3 0x14200 bored systqmp 72505 223646 0 0 3 0x14200 bored systq 83594 409759 0 0 3 0x40014200 bored softclock 83822 322283 0 0 3 0x40014200 idle0 51684 157370 0 0 3 0x14200 bored smr 1 368229 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks CPU 0: exclusive mutex &map->mtx r = 0 (0xffffffff82514a90) #0 witness_lock+0x52e sys/kern/subr_witness.c:1164 #1 mtx_enter_try+0x102 #2 mtx_enter+0x4b sys/kern/kern_lock.c:266 #3 vm_map_lock_ln+0x60 sys/uvm/uvm_map.c:5418 #4 malloc+0x764 sys/kern/kern_malloc.c:310 #5 ktrsyscall+0x192 sys/kern/kern_ktrace.c:174 #6 syscall+0x35b mi_syscall sys/sys/syscall_mi.h:76 [inline] #6 syscall+0x35b sys/arch/amd64/amd64/trap.c:570 #7 Xsyscall+0x128 exclusive mutex /syzkaller/managers/multicore/kernel/sys/kern/kern_malloc.c:104 r = 0 (0xffffffff82480af0) #0 witness_lock+0x52e sys/kern/subr_witness.c:1164 #1 mtx_enter_try+0x102 #2 mtx_enter+0x4b sys/kern/kern_lock.c:266 #3 malloc+0x23b sys/kern/kern_malloc.c:209 #4 ktrsyscall+0x192 sys/kern/kern_ktrace.c:174 #5 syscall+0x35b mi_syscall sys/sys/syscall_mi.h:76 [inline] #5 syscall+0x35b sys/arch/amd64/amd64/trap.c:570 #6 Xsyscall+0x128 Process 85634 (syz-executor.0) thread 0xffff800020ae6c48 (177406) exclusive kernel_lock &kernel_lock r = 0 (0xffffffff82667478) #0 witness_lock+0x52e sys/kern/subr_witness.c:1164 #1 syscall+0x348 mi_syscall sys/sys/syscall_mi.h:75 [inline] #1 syscall+0x348 sys/arch/amd64/amd64/trap.c:570 #2 Xsyscall+0x128 exclusive mutex &map->mtx r = 0 (0xffffffff82514a90) #0 witness_lock+0x52e sys/kern/subr_witness.c:1164 #1 mtx_enter_try+0x102 #2 mtx_enter+0x4b sys/kern/kern_lock.c:266 #3 vm_map_lock_ln+0x60 sys/uvm/uvm_map.c:5418 #4 malloc+0x764 sys/kern/kern_malloc.c:310 #5 ktrsyscall+0x192 sys/kern/kern_ktrace.c:174 #6 syscall+0x35b mi_syscall sys/sys/syscall_mi.h:76 [inline] #6 syscall+0x35b sys/arch/amd64/amd64/trap.c:570 #7 Xsyscall+0x128 exclusive mutex /syzkaller/managers/multicore/kernel/sys/kern/kern_malloc.c:104 r = 0 (0xffffffff82480af0) #0 witness_lock+0x52e sys/kern/subr_witness.c:1164 #1 mtx_enter_try+0x102 #2 mtx_enter+0x4b sys/kern/kern_lock.c:266 #3 malloc+0x23b sys/kern/kern_malloc.c:209 #4 ktrsyscall+0x192 sys/kern/kern_ktrace.c:174 #5 syscall+0x35b mi_syscall sys/sys/syscall_mi.h:76 [inline] #5 syscall+0x35b sys/arch/amd64/amd64/trap.c:570 #6 Xsyscall+0x128 Process 22017 (softnet) thread 0xffff800020a28270 (355344) shared rwlock netlock r = 0 (0xffffffff824c4708) #0 witness_lock+0x52e sys/kern/subr_witness.c:1164 #1 if_input_process+0x84 sys/net/if.c:942 #2 ifiq_process+0x80 sys/net/ifq.c:607 #3 taskq_thread+0x9c sys/kern/kern_task.c:369 #4 proc_trampoline+0x1c shared rwlock softnet r = 0 (0xffff80000002b0e0) #0 witness_lock+0x52e sys/kern/subr_witness.c:1164 #1 taskq_thread+0x8f sys/kern/kern_task.c:368 #2 proc_trampoline+0x1c ddb{0}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 9518 6423K 7175K 78643K 11090 0 pcb 13 8K 8K 78643K 63 0 rtable 105 3K 3K 78643K 279 0 ifaddr 73 14K 14K 78643K 98 0 counters 39 33K 33K 78643K 39 0 ioctlops 0 0K 4K 78643K 1476 0 iov 0 0K 24K 78643K 73 0 mount 1 1K 1K 78643K 1 0 vnodes 1227 77K 77K 78643K 1372 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 4 0 VM map 2 1K 1K 78643K 2 0 sem 12 0K 0K 78643K 46 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 196K 290K 78643K 12766 0 file desc 4 9K 25K 78643K 235 0 sigio 0 0K 0K 78643K 12 0 proc 60 63K 95K 78643K 484 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 18 0 in_multi 46 2K 2K 78643K 72 0 ether_multi 1 0K 0K 78643K 5 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 49 228K 228K 78643K 49 0 exec 0 0K 1K 78643K 237 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 118 22K 38K 78643K 1790 0 UVM aobj 10 2K 2K 78643K 10 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 31 0 NDP 12 0K 0K 78643K 22 0 temp 131 3018K 3083K 78643K 10065 0 kqueue 3 4K 14K 78643K 34 0 SYN cache 2 16K 16K 78643K 2 0 ddb{0}> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle arp 64 8 0 2 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtpcb 80 33 0 31 1 0 1 1 0 8 0 rtentry 112 59 0 15 2 0 2 2 0 8 0 unpcb 120 214 0 204 2 0 2 2 0 8 1 syncache 264 13 0 13 3 3 0 1 0 8 0 tcpqe 32 66 0 66 1 1 0 1 0 8 0 tcpcb 544 123 0 117 1 0 1 1 0 8 0 inpcb 280 486 0 477 2 0 2 2 0 8 1 nd6 48 7 0 3 1 0 1 1 0 8 0 pffrag 232 2 0 2 1 1 0 1 0 482 0 pffrnode 88 2 0 2 1 1 0 1 0 8 0 pffrent 40 47 0 47 1 1 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 32 0 6 1 0 1 1 0 8 0 pfstkey 112 32 0 6 1 0 1 1 0 8 0 pfstate 328 32 0 6 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 256 280 0 67 14 0 14 14 0 8 0 art_table 32 281 0 67 2 0 2 2 0 8 0 art_node 16 58 0 18 1 0 1 1 0 8 0 sysvmsgpl 40 32 0 19 1 0 1 1 0 8 0 semupl 112 2 0 2 1 1 0 1 0 8 0 semapl 112 40 0 30 1 0 1 1 0 8 0 shmpl 112 8 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 1716 0 308 46 0 46 46 0 8 0 ffsino 272 1716 0 308 95 0 95 95 0 8 0 nchpl 144 2262 0 663 61 0 61 61 0 8 0 uvmvnodes 72 1880 0 0 35 0 35 35 0 8 0 vnodes 208 1880 0 0 99 0 99 99 0 8 0 namei 1024 6189 0 6189 1 0 1 1 0 8 1 percpumem 16 30 0 0 1 0 1 1 0 8 0 vmpool 560 2 0 2 1 0 1 1 0 8 1 scxspl 192 6630 0 6630 8 7 1 7 0 8 1 plimitpl 152 35 0 27 1 0 1 1 0 8 0 sigapl 432 431 0 417 3 1 2 3 0 8 0 futexpl 56 3860 0 3860 1 0 1 1 0 8 1 knotepl 112 101 0 82 1 0 1 1 0 8 0 kqueuepl 104 60 0 58 1 0 1 1 0 8 0 pipelkpl 48 196 0 186 1 0 1 1 0 8 0 pipepl 120 392 0 373 2 1 1 2 0 8 0 fdescpl 496 432 0 417 3 0 3 3 0 8 0 filepl 152 3000 0 2899 7 1 6 6 0 8 1 lockfpl 104 119 0 118 1 0 1 1 0 8 0 lockfspl 48 33 0 32 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 96 229 0 220 1 0 1 1 0 8 0 zombiepl 144 417 0 417 1 0 1 1 0 8 1 processpl 960 448 0 417 5 0 5 5 0 8 0 procpl 624 954 0 914 4 0 4 4 0 8 0 sockpl 400 750 0 729 6 0 6 6 0 8 3 mcl64k 65536 5 0 0 1 0 1 1 0 8 0 mcl12k 12288 3 0 0 1 0 1 1 0 8 0 mcl9k 9216 2 0 0 1 0 1 1 0 8 0 mcl8k 8192 3 0 0 1 0 1 1 0 8 0 mcl4k 4096 5 0 0 1 0 1 1 0 8 0 mcl2k 2048 163 0 0 20 0 20 20 0 8 0 mtagpl 80 26 0 0 1 0 1 1 0 8 0 mbufpl 256 362 0 0 22 0 22 22 0 8 0 bufpl 280 6861 0 1340 395 0 395 395 0 8 0 anonpl 16 60243 0 44392 82 1 81 81 0 125 16 amapchunkpl 152 3124 0 2994 20 7 13 19 0 158 6 amappl16 192 2019 0 1166 55 4 51 55 0 8 8 amappl15 184 162 0 156 1 0 1 1 0 8 0 amappl14 176 42 0 38 1 0 1 1 0 8 0 amappl12 160 28 0 26 2 1 1 1 0 8 0 amappl11 152 60 0 45 1 0 1 1 0 8 0 amappl10 144 106 0 98 1 0 1 1 0 8 0 amappl9 136 618 0 615 1 0 1 1 0 8 0 amappl8 128 131 0 105 1 0 1 1 0 8 0 amappl7 120 201 0 188 1 0 1 1 0 8 0 amappl6 112 59 0 52 1 0 1 1 0 8 0 amappl5 104 138 0 124 1 0 1 1 0 8 0 amappl4 96 685 0 655 1 0 1 1 0 8 0 amappl3 88 123 0 115 1 0 1 1 0 8 0 amappl2 80 2573 0 2507 3 1 2 3 0 8 0 amappl1 72 19715 0 19282 27 17 10 21 0 8 0 amappl 80 1217 0 1176 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 9 0 0 1 0 1 1 0 8 0 uaddrrnd 24 434 0 419 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 434 0 419 1 0 1 1 0 8 0 vmmpekpl 168 7841 0 7803 2 0 2 2 0 8 0 vmmpepl 168 61417 0 59492 134 16 118 122 0 357 27 vmsppl 368 433 0 419 2 0 2 2 0 8 0 pdppl 4096 875 0 838 6 0 6 6 0 8 1 pvpl 32 191632 0 172689 198 1 197 197 0 265 43 pmappl 232 433 0 419 3 1 2 2 0 8 1 extentpl 40 46 0 29 1 0 1 1 0 8 0 phpool 112 182 0 3 6 0 6 6 0 8 0