panic: pool_cache_itemW_AmRaNgIiNcG:_ cShPeLck : NmOTb uLfpOlW EcREpDu OfNr eeS YlSiCsAtLL mo13d7i f-i7ed84: 0i0t eEm XaITd d0r a0 x ffStopped at savectx+0xb1: movl $0,%gs:0x530 TID PID UID PRFLAGS PFLAGS CPU COMMAND *172326 4977 0 0x2 0 0 syz-executor.0 4177 63874 0 0x12 0 1 sshd savectx(6,0,7f7ffffec900,89,95efdcd41c0,7f7ffffecdc0) at savectx+0xb1 end of kernel end trace frame: 0x7f7ffffecdb0, 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 0xfffffd8061bcd900+24 0x3ba3b29c3c710907!=0xc45c4f1c5bac0d07 ddb{0}> trace savectx(6,0,7f7ffffec900,89,95efdcd41c0,7f7ffffecdc0) at savectx+0xb1 end of kernel end trace frame: 0x7f7ffffecdb0, count: -1 ddb{0}> show registers rdi 0 rsi 0 rbp 0xffff800024c0bc50 rbx 0 rdx 0xffff800020a5ec60 rcx 0 rax 0x38 r8 0xffffffff814de02f kprintf+0x16f r9 0x1 r10 0x25 r11 0xcd913f2a7dd61b86 r12 0 r13 0 r14 0xffff800020a5ec60 r15 0 rip 0xffffffff81a263f1 savectx+0xb1 cs 0x8 rflags 0x46 rsp 0xffff800024c0bbd0 ss 0x10 savectx+0xb1: movl $0,%gs:0x530 ddb{0}> show proc PROC (syz-executor.0) pid=172326 stat=onproc flags process=2 proc=0 pri=80, usrpri=80, nice=20 forw=0xffffffffffffffff, list=0xffff800020ab09f8,0xffff800020a5fb40 process=0xffff800020adca80 user=0xffff800024c06000, vmspace=0xfffffd807f00a8a0 estcpu=36, cpticks=2, pctcpu=0.12 user=0, sys=1, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 39983 478261 6647 0 2 0 syz-executor.1 39983 286912 6647 0 3 0x4000080 fifor syz-executor.1 39983 2479 6647 0 3 0x4000080 fsleep syz-executor.1 * 4977 172326 50591 0 7 0x2 syz-executor.0 6647 465244 50591 0 3 0x82 nanosleep syz-executor.1 11068 475164 1 0 3 0x100083 ttyin getty 82844 348444 0 0 3 0x14200 acct acct 35893 8034 0 0 3 0x14200 bored sosplice 50591 7713 98408 0 3 0x82 thrsleep syz-fuzzer 50591 335889 98408 0 3 0x4000082 nanosleep syz-fuzzer 50591 449229 98408 0 3 0x4000082 thrsleep syz-fuzzer 50591 475661 98408 0 3 0x4000082 thrsleep syz-fuzzer 50591 285292 98408 0 3 0x4000082 nanosleep syz-fuzzer 50591 309482 98408 0 3 0x4000082 thrsleep syz-fuzzer 50591 210044 98408 0 3 0x4000082 thrsleep syz-fuzzer 50591 491269 98408 0 3 0x4000082 thrsleep syz-fuzzer 50591 61096 98408 0 3 0x4000082 kqread syz-fuzzer 50591 311148 98408 0 3 0x4000082 thrsleep syz-fuzzer 98408 416717 63874 0 3 0x10008a pause ksh 63874 4177 56676 0 7 0x12 sshd 56676 310616 1 0 3 0x80 select sshd 81716 241851 70159 74 3 0x100092 bpf pflogd 70159 305110 1 0 3 0x80 netio pflogd 9814 363578 82609 73 3 0x100090 kqread syslogd 82609 52189 1 0 3 0x100082 netio syslogd 47901 162445 1 77 3 0x100090 poll dhclient 49661 116401 1 0 3 0x80 poll dhclient 69530 427942 0 0 2 0x14200 zerothread 85372 107830 0 0 3 0x14200 aiodoned aiodoned 9950 475950 0 0 3 0x14200 syncer update 45749 24957 0 0 3 0x14200 cleaner cleaner 55050 519437 0 0 3 0x14200 reaper reaper 90521 503268 0 0 3 0x14200 pgdaemon pagedaemon 25681 425783 0 0 3 0x14200 bored crynlk 82576 405119 0 0 3 0x14200 bored crypto 34968 373423 0 0 3 0x40014200 acpi0 acpi0 29190 139372 0 0 3 0x40014200 idle1 52206 488189 0 0 3 0x14200 bored softnet 94193 90311 0 0 3 0x14200 bored systqmp 96778 454044 0 0 3 0x14200 bored systq 12940 450546 0 0 3 0x40014200 bored softclock 58935 436865 0 0 3 0x40014200 idle0 51119 409427 0 0 3 0x14200 bored smr 1 299615 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 (0xffffffff82621620) #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 vm_map_lock_ln+0x60 sys/uvm/uvm_map.c:5348 #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:66 [inline] #6 syscall+0x35b sys/arch/amd64/amd64/trap.c:555 #7 Xsyscall+0x128 exclusive mutex /syzkaller/managers/multicore/kernel/sys/kern/kern_malloc.c:104 r = 0 (0xffffffff825049d0) #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 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:66 [inline] #5 syscall+0x35b sys/arch/amd64/amd64/trap.c:555 #6 Xsyscall+0x128 Process 4977 (syz-executor.0) thread 0xffff800020a5ec60 (172326) exclusive kernel_lock &kernel_lock r = 0 (0xffffffff82622388) #0 witness_lock+0x52e sys/kern/subr_witness.c:1163 #1 syscall+0x348 mi_syscall sys/sys/syscall_mi.h:65 [inline] #1 syscall+0x348 sys/arch/amd64/amd64/trap.c:555 #2 Xsyscall+0x128 exclusive mutex &map->mtx r = 0 (0xffffffff82621620) #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 vm_map_lock_ln+0x60 sys/uvm/uvm_map.c:5348 #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:66 [inline] #6 syscall+0x35b sys/arch/amd64/amd64/trap.c:555 #7 Xsyscall+0x128 exclusive mutex /syzkaller/managers/multicore/kernel/sys/kern/kern_malloc.c:104 r = 0 (0xffffffff825049d0) #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 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:66 [inline] #5 syscall+0x35b sys/arch/amd64/amd64/trap.c:555 #6 Xsyscall+0x128 Process 63874 (sshd) thread 0xffff800020ac1b38 (4177) exclusive rwlock netlock r = 0 (0xffffffff824fc348) #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 dofilewritev+0x1b7 sys/kern/sys_generic.c:364 #4 sys_write+0x83 sys/kern/sys_generic.c:284 #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{0}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim Kern Lim devbuf 9660 7332K 7851K 78643K 28516 0 0 pcb 13 12K 14K 78643K 1673 0 0 rtable 143 15K 17K 78643K 5212 0 0 ifaddr 107 27K 29K 78643K 1412 0 0 counters 39 33K 33K 78643K 39 0 0 ioctlops 0 0K 4K 78643K 2497 0 0 iov 0 0K 28K 78643K 1551 0 0 mount 1 1K 1K 78643K 1 0 0 vnodes 1233 77K 78K 78643K 8212 0 0 UFS quota 1 32K 32K 78643K 1 0 0 UFS mount 5 36K 36K 78643K 5 0 0 shm 2 1K 9K 78643K 111 0 0 VM map 72 36K 36K 78643K 112 0 0 sem 12 0K 0K 78643K 1842 0 0 dirhash 12 2K 2K 78643K 12 0 0 ACPI 1808 196K 290K 78643K 12765 0 0 file desc 5 13K 25K 78643K 8179 0 0 sigio 0 0K 0K 78643K 116 0 0 proc 62 63K 95K 78643K 2927 0 0 subproc 32 2K 2K 78643K 739 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 1127 0 0 in_multi 36 2K 3K 78643K 901 0 0 ether_multi 1 0K 0K 78643K 106 0 0 mrt 1 0K 0K 78643K 41 0 0 ISOFS mount 1 32K 32K 78643K 1 0 0 MSDOSFS mount 1 16K 16K 78643K 1 0 0 ttys 204 901K 901K 78643K 204 0 0 exec 0 0K 1K 78643K 1581 0 0 pfkey data 0 0K 4K 78643K 5 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 218 625K 626K 78643K 29555 0 0 UVM aobj 130 5K 5K 78643K 144 0 0 memdesc 1 4K 4K 78643K 1 0 0 crypto data 1 1K 1K 78643K 1 0 0 ip6_options 0 0K 0K 78643K 1707 0 0 NDP 25 0K 1K 78643K 448 0 0 temp 267 3564K 4201K 78643K 240184 0 0 kqueue 0 0K 0K 78643K 66 0 0 SYN cache 2 16K 16K 78643K 2 0 0 ddb{0}> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle arp 64 193 0 183 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtpcb 80 906 0 904 1 0 1 1 0 8 0 rtentry 112 897 0 846 2 0 2 2 0 8 0 unpcb 120 4353 0 4338 8 7 1 2 0 8 0 syncache 264 37 0 37 15 15 0 1 0 8 0 sackhl 24 3 0 3 3 3 0 1 0 8 0 tcpqe 32 151 0 151 6 6 0 1 0 8 0 tcpcb 544 3426 0 3422 20 19 1 12 0 8 0 inpcb 280 11169 0 11158 63 61 2 13 0 8 1 rttmr 72 12 0 11 2 1 1 1 0 8 0 ip6q 72 1 0 1 1 1 0 1 0 8 0 nd6 48 109 0 106 5 4 1 1 0 8 0 pkpcb 40 94 0 94 18 17 1 1 0 8 1 swfcl 56 4 0 0 1 0 1 1 0 8 0 ppxss 1128 193 0 193 19 18 1 1 0 8 1 pffrag 232 192 0 191 21 20 1 1 0 482 0 pffrnode 88 192 0 191 21 20 1 1 0 8 0 pffrent 40 6107 0 6085 20 19 1 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 24 608 0 561 1 0 1 1 0 8 0 pfstkey 112 608 0 561 4 1 3 3 0 8 0 pfstate 328 608 0 560 15 9 6 9 0 8 0 pfrule 1360 21 0 16 2 1 1 2 0 8 0 art_heap8 4096 27 0 26 15 14 1 4 0 8 0 art_heap4 256 3558 0 3276 49 30 19 19 0 8 0 art_table 32 3585 0 3302 7 4 3 3 0 8 0 art_node 16 888 0 841 1 0 1 1 0 8 0 sysvmsgpl 40 6 0 4 1 0 1 1 0 8 0 semapl 112 1840 0 1830 1 0 1 1 0 8 0 shmpl 112 142 0 14 4 0 4 4 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 14537 0 13098 47 0 47 47 0 8 0 ffsino 272 14537 0 13098 97 0 97 97 0 8 0 nchpl 144 31379 0 30954 61 41 20 61 0 8 0 uvmvnodes 72 6281 0 0 115 0 115 115 0 8 0 vnodes 208 6281 0 0 331 0 331 331 0 8 0 namei 1024 110577 0 110577 6 5 1 1 0 8 1 percpumem 16 30 0 0 1 0 1 1 0 8 0 vcpupl 1984 72 0 2 9 0 9 9 0 8 0 vmpool 552 110 0 40 7 2 5 5 0 8 0 scsiplug 64 11 0 11 8 8 0 1 0 8 0 scxspl 192 89945 0 89945 54 51 3 7 0 8 3 plimitpl 152 701 0 693 1 0 1 1 0 8 0 sigapl 432 8259 0 8244 3 1 2 3 0 8 0 futexpl 56 183717 0 183716 3 2 1 1 0 8 0 knotepl 112 2308 0 2287 13 12 1 3 0 8 0 kqueuepl 104 2423 0 2420 4 3 1 4 0 8 0 pipepl 112 5626 0 5607 17 16 1 2 0 8 0 fdescpl 488 8260 0 8244 3 0 3 3 0 8 0 filepl 152 78253 0 78146 77 72 5 14 0 8 0 lockfpl 104 2768 0 2767 1 0 1 1 0 8 0 lockfspl 48 928 0 927 1 0 1 1 0 8 0 sessionpl 112 62 0 51 1 0 1 1 0 8 0 pgrppl 48 162 0 151 1 0 1 1 0 8 0 ucredpl 96 8777 0 8768 1 0 1 1 0 8 0 zombiepl 144 8248 0 8248 4 3 1 1 0 8 1 processpl 896 8281 0 8248 4 0 4 4 0 8 0 procpl 632 26494 0 26450 8 3 5 5 0 8 1 srpgc 64 68 0 68 23 23 0 1 0 8 0 sosppl 128 168 0 168 28 28 0 1 0 8 0 sockpl 384 16678 0 16654 98 94 4 23 0 8 1 mcl64k 65536 669 0 0 71 37 34 34 0 8 0 mcl16k 16384 36 0 0 5 3 2 3 0 8 0 mcl12k 12288 17 0 0 2 0 2 2 0 8 0 mcl9k 9216 25 0 0 2 0 2 2 0 8 0 mcl8k 8192 33 0 0 4 1 3 3 0 8 0 mcl4k 4096 26 0 0 4 1 3 3 0 8 0 mcl2k2 2112 8 0 0 1 0 1 1 0 8 0 mcl2k 2048 245 0 0 24 10 14 24 0 8 0 mtagpl 80 108 0 0 1 0 1 1 0 8 0 mbufpl 256 1230 0 0 49 0 49 49 0 8 0 bufpl 256 30799 0 23751 441 0 441 441 0 8 0 anonpl 16 1028544 0 1005405 300 200 100 115 0 124 6 amapchunkpl 152 58539 0 58391 103 93 10 20 0 158 2 amappl16 192 49145 0 47778 295 226 69 83 0 8 0 amappl15 184 188 0 187 1 0 1 1 0 8 0 amappl14 176 2773 0 2770 1 0 1 1 0 8 0 amappl13 168 805 0 804 6 5 1 1 0 8 0 amappl12 160 458 0 457 2 1 1 1 0 8 0 amappl11 152 179 0 163 1 0 1 1 0 8 0 amappl10 144 2114 0 2109 1 0 1 1 0 8 0 amappl9 136 2057 0 2050 1 0 1 1 0 8 0 amappl8 128 1590 0 1552 2 0 2 2 0 8 0 amappl7 120 2297 0 2287 1 0 1 1 0 8 0 amappl6 112 135 0 120 1 0 1 1 0 8 0 amappl5 104 914 0 900 1 0 1 1 0 8 0 amappl4 96 7958 0 7921 1 0 1 1 0 8 0 amappl3 88 3277 0 3264 1 0 1 1 0 8 0 amappl2 80 63205 0 63125 3 1 2 3 0 8 0 amappl1 72 195472 0 195026 25 15 10 20 0 8 0 amappl 80 27561 0 27483 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 64 143 0 14 3 0 3 3 0 8 0 uaddrrnd 24 8370 0 8244 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 8370 0 8244 1 0 1 1 0 8 0 vmmpekpl 168 66730 0 66684 5 2 3 3 0 8 0 vmmpepl 168 1062554 0 1059796 479 326 153 160 0 357 28 vmsppl 368 8259 0 8244 2 0 2 2 0 8 0 pdppl 4096 16747 0 16638 17 3 14 14 0 8 0 pvpl 32 2642351 0 2619835 511 305 206 218 0 265 19 pmappl 232 8369 0 8284 7 1 6 6 0 8 1 extentpl 40 41 0 26 1 0 1 1 0 8 0 phpool 112 811 0 126 20 0 20 20 0 8 0