panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 132748 7865 0 0x2 0 1K syz-executor.1 *130767 78756 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823ebefd) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd806444fd00,244,22c,2) at m_copym+0x583 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ada100) at tcp_output+0x15ba sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd806eaf3968,9,fffffd806444fc00,0,0,ffff800020e41390) at tcp_usrreq+0xa55 sosend(fffffd806eaf3968,0,ffff800020e63808,0,0,80) at sosend+0x671 sys/kern/uipc_socket.c:555 dofilewritev(ffff800020e41390,4,ffff800020e63808,0,ffff800020e638f0) at dofilewritev+0x1b6 sys/kern/sys_generic.c:365 sys_write(ffff800020e41390,ffff800020e638a0,ffff800020e638f0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff800020e63970) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff800020e63970) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff6ae0, count: 5 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 m_copym0: short mbuf chain ddb{0}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823ebefd) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd806444fd00,244,22c,2) at m_copym+0x583 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ada100) at tcp_output+0x15ba sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd806eaf3968,9,fffffd806444fc00,0,0,ffff800020e41390) at tcp_usrreq+0xa55 sosend(fffffd806eaf3968,0,ffff800020e63808,0,0,80) at sosend+0x671 sys/kern/uipc_socket.c:555 dofilewritev(ffff800020e41390,4,ffff800020e63808,0,ffff800020e638f0) at dofilewritev+0x1b6 sys/kern/sys_generic.c:365 sys_write(ffff800020e41390,ffff800020e638a0,ffff800020e638f0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff800020e63970) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff800020e63970) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff6ae0, count: -10 ddb{0}> show registers rdi 0 rsi 0x1 rbp 0xffff800020e632d0 rbx 0xffff800020e63380 rdx 0x8b rcx 0x2 rax 0x1 r8 0xffffffff82139aef kprintf+0x16f r9 0x1 r10 0x2 r11 0x2790cd5b8e6704b1 r12 0x3000000008 r13 0xffff800020e632e0 r14 0x100 r15 0x1 rip 0xffffffff82024518 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800020e632c0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (sshd) pid=130767 stat=onproc flags process=12 proc=0 pri=50, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff800020e40280,0xffff800020e41af0 process=0xffff800020e39350 user=0xffff800020e5e000, vmspace=0xfffffd806e908cf8 estcpu=0, cpticks=1, pctcpu=0.5 user=0, sys=0, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 73702 40049 63633 0 2 0 syz-executor.0 73702 263358 63633 0 3 0x4000080 fsleep syz-executor.0 87431 272198 0 0 3 0x14200 bored sosplice 7865 132748 53431 0 7 0x2 syz-executor.1 63633 386450 53431 0 3 0x82 nanosleep syz-executor.0 53431 24330 56971 0 3 0x82 thrsleep syz-fuzzer 53431 304532 56971 0 3 0x4000082 nanosleep syz-fuzzer 53431 74169 56971 0 3 0x4000082 thrsleep syz-fuzzer 53431 131852 56971 0 3 0x4000082 kqread syz-fuzzer 53431 82102 56971 0 3 0x4000082 thrsleep syz-fuzzer 53431 183883 56971 0 3 0x4000082 nanosleep syz-fuzzer 53431 209141 56971 0 3 0x4000082 thrsleep syz-fuzzer 53431 164230 56971 0 3 0x4000082 thrsleep syz-fuzzer 53431 27980 56971 0 3 0x4000082 thrsleep syz-fuzzer 53431 369384 56971 0 3 0x4000082 thrsleep syz-fuzzer 56971 455286 78756 0 3 0x10008a pause ksh *78756 130767 85624 0 7 0x12 sshd 64253 238333 1 0 3 0x100083 ttyin getty 85624 476640 1 0 3 0x80 select sshd 22882 35536 38082 74 3 0x100092 bpf pflogd 38082 365855 1 0 3 0x80 netio pflogd 93236 338369 68504 73 3 0x100090 kqread syslogd 68504 309121 1 0 3 0x100082 netio syslogd 20388 321399 1 77 3 0x100090 poll dhclient 37915 326685 1 0 3 0x80 poll dhclient 10623 517776 0 0 3 0x14200 bored smr 68341 518364 0 0 2 0x14200 zerothread 23303 351051 0 0 3 0x14200 aiodoned aiodoned 94030 13271 0 0 3 0x14200 syncer update 60106 340878 0 0 3 0x14200 cleaner cleaner 62292 354644 0 0 3 0x14200 reaper reaper 90214 303316 0 0 3 0x14200 pgdaemon pagedaemon 85688 165913 0 0 3 0x14200 bored crynlk 45997 329428 0 0 3 0x14200 bored crypto 8654 73994 0 0 3 0x40014200 acpi0 acpi0 79912 122720 0 0 3 0x40014200 idle1 52973 43706 0 0 3 0x14200 bored softnet 39841 23186 0 0 3 0x14200 bored systqmp 20699 141845 0 0 3 0x14200 bored systq 79368 437217 0 0 3 0x40014200 bored softclock 14507 139874 0 0 3 0x40014200 idle0 1 144577 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks Process 53431 (syz-fuzzer) thread 0xffff800020e41d50 (82102) shared rwlock vmmaplk r = 0 (0xfffffd806e9088c0) #0 witness_lock+0x4c7 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4c7 sys/kern/subr_witness.c:1164 #1 uvm_map_inentry_fix+0xa3 vm_map_lock_read_ln sys/uvm/uvm_map.c:5467 [inline] #1 uvm_map_inentry_fix+0xa3 sys/uvm/uvm_map.c:1858 #2 uvm_map_inentry+0xd2 sys/uvm/uvm_map.c:1890 #3 syscall+0x397 mi_syscall sys/sys/syscall_mi.h:81 [inline] #3 syscall+0x397 sys/arch/amd64/amd64/trap.c:570 #4 Xsyscall+0x128 exclusive kernel_lock &kernel_lock r = 0 (0xffffffff82902548) #0 witness_lock+0x4c7 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4c7 sys/kern/subr_witness.c:1164 #1 uvm_map_inentry+0xbe sys/uvm/uvm_map.c:1890 #2 syscall+0x397 mi_syscall sys/sys/syscall_mi.h:81 [inline] #2 syscall+0x397 sys/arch/amd64/amd64/trap.c:570 #3 Xsyscall+0x128 Process 78756 (sshd) thread 0xffff800020e41390 (130767) exclusive rwlock netlock r = 0 (0xffffffff82753778) #0 witness_lock+0x4c7 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4c7 sys/kern/subr_witness.c:1164 #1 solock+0x5a sys/kern/uipc_socket2.c:282 #2 sosend+0x559 sys/kern/uipc_socket.c:543 #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{0}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 9526 6490K 6801K 78643K 11276 0 pcb 13 8K 8K 78643K 82 0 rtable 124 7K 7K 78643K 401 0 ifaddr 78 15K 16K 78643K 160 0 counters 43 33K 34K 78643K 65 0 ioctlops 0 0K 4K 78643K 1536 0 iov 0 0K 32K 78643K 54 0 mount 1 1K 1K 78643K 1 0 vnodes 1224 77K 77K 78643K 1429 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 6 0 VM map 2 1K 1K 78643K 2 0 sem 12 0K 0K 78643K 90 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1824 197K 290K 78643K 13058 0 file desc 5 13K 25K 78643K 411 0 sigio 0 0K 0K 78643K 4 0 proc 61 63K 95K 78643K 478 0 subproc 32 2K 2K 78643K 34 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 21 0 in_multi 49 2K 2K 78643K 125 0 ether_multi 1 0K 0K 78643K 14 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 49 228K 228K 78643K 49 0 exec 0 0K 1K 78643K 236 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 128 71K 71K 78643K 2395 0 UVM aobj 9 2K 2K 78643K 9 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 57 0 NDP 12 0K 0K 78643K 37 0 temp 122 3868K 3943K 78643K 14697 0 kqueue 3 4K 9K 78643K 28 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 7 0 0 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 65 0 19 2 0 2 2 0 8 0 unpcb 120 230 0 220 1 0 1 1 0 8 0 syncache 264 9 0 9 2 1 1 1 0 8 1 tcpqe 32 1 0 1 1 0 1 1 0 8 1 tcpcb 544 194 0 190 2 0 2 2 0 8 1 inpcb 296 1721 0 1712 3 1 2 2 0 8 1 nd6 48 19 0 12 1 0 1 1 0 8 0 pkpcb 40 2 0 2 1 1 0 1 0 8 0 ppxss 1128 1 0 1 1 0 1 1 0 8 1 pffrag 232 5 0 4 2 1 1 1 0 482 0 pffrnode 88 5 0 4 2 1 1 1 0 8 0 pffrent 40 12 0 11 2 1 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 pfrke_plain 160 10 0 4 1 0 1 1 0 8 0 pfrktable 1344 33 0 28 1 0 1 1 0 8 0 pfpktdelay 56 141 0 141 2 1 1 1 0 8 1 pfstitem 24 13 0 7 1 0 1 1 0 8 0 pfstkey 112 13 0 7 1 0 1 1 0 8 0 pfstate 328 13 0 7 2 1 1 2 0 8 0 pfrule 1360 29 0 20 2 1 1 2 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 241 0 40 13 0 13 13 0 8 0 art_table 32 242 0 40 2 0 2 2 0 8 0 art_node 16 64 0 22 1 0 1 1 0 8 0 sysvmsgpl 40 11 0 9 1 0 1 1 0 8 0 semapl 112 86 0 76 1 0 1 1 0 8 0 shmpl 112 7 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1962 0 559 89 0 89 89 0 8 0 ffsino 272 1962 0 559 94 0 94 94 0 8 0 nchpl 144 2679 0 1070 60 0 60 60 0 8 0 rtmask 32 8 0 8 1 1 0 1 0 8 0 uvmvnodes 72 2150 0 0 40 0 40 40 0 8 0 vnodes 208 2150 0 0 114 0 114 114 0 8 0 namei 1024 7371 0 7370 2 1 1 1 0 8 0 percpumem 16 43 0 11 1 0 1 1 0 8 0 vcpupl 1984 5 0 0 1 0 1 1 0 8 0 vmpool 560 5 0 0 1 0 1 1 0 8 0 pfiaddrpl 120 11 0 8 1 0 1 1 0 8 0 scxspl 192 8095 0 8094 8 7 1 7 0 8 0 plimitpl 152 39 0 31 1 0 1 1 0 8 0 sigapl 424 627 0 595 4 0 4 4 0 8 0 futexpl 56 7671 0 7670 2 1 1 1 0 8 0 knotepl 112 90 0 71 1 0 1 1 0 8 0 kqueuepl 144 82 0 79 1 0 1 1 0 8 0 pipepl 304 147 0 137 2 1 1 2 0 8 0 fdescpl 496 611 0 595 3 0 3 3 0 8 0 filepl 152 4538 0 4437 6 1 5 6 0 8 1 lockfpl 104 106 0 105 1 0 1 1 0 8 0 lockfspl 48 32 0 31 1 0 1 1 0 8 0 sessionpl 112 18 0 7 1 0 1 1 0 8 0 pgrppl 48 24 0 13 1 0 1 1 0 8 0 ucredpl 96 366 0 357 1 0 1 1 0 8 0 zombiepl 144 595 0 595 1 0 1 1 0 8 1 processpl 984 627 0 595 5 0 5 5 0 8 0 procpl 624 1606 0 1564 4 0 4 4 0 8 0 sosppl 128 2 0 2 1 1 0 1 0 8 0 sockpl 400 1991 0 1971 6 2 4 4 0 8 2 mcl64k 65536 9 0 0 2 0 2 2 0 8 0 mcl16k 16384 3 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 2 0 0 1 0 1 1 0 8 0 mcl4k 4096 6 0 0 1 0 1 1 0 8 0 mcl2k2 2112 2 0 0 1 0 1 1 0 8 0 mcl2k 2048 182 0 0 22 0 22 22 0 8 0 mtagpl 96 42 0 0 2 0 2 2 0 8 0 mbufpl 256 534 0 0 31 0 31 31 0 8 0 bufpl 280 4146 0 136 287 0 287 287 0 8 0 anonpl 16 69415 0 52376 85 1 84 84 0 124 13 amapchunkpl 152 3639 0 3482 15 8 7 14 0 158 0 amappl16 192 3108 0 2198 58 4 54 57 0 8 8 amappl15 184 1 0 0 1 0 1 1 0 8 0 amappl14 176 202 0 194 1 0 1 1 0 8 0 amappl13 168 33 0 29 1 0 1 1 0 8 0 amappl12 160 11 0 8 1 0 1 1 0 8 0 amappl11 152 58 0 43 1 0 1 1 0 8 0 amappl10 144 21 0 16 1 0 1 1 0 8 0 amappl9 136 395 0 393 1 0 1 1 0 8 0 amappl8 128 368 0 333 2 0 2 2 0 8 0 amappl7 120 125 0 112 1 0 1 1 0 8 0 amappl6 112 20 0 19 2 1 1 1 0 8 0 amappl5 104 516 0 499 1 0 1 1 0 8 0 amappl4 96 489 0 461 1 0 1 1 0 8 0 amappl3 88 282 0 275 1 0 1 1 0 8 0 amappl2 80 3959 0 3889 2 0 2 2 0 8 0 amappl1 72 23775 0 23346 23 13 10 18 0 8 0 amappl 80 1874 0 1822 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 8 0 0 1 0 1 1 0 8 0 uaddrrnd 24 616 0 595 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 616 0 595 1 0 1 1 0 8 0 vmmpekpl 168 8650 0 8612 2 0 2 2 0 8 0 vmmpepl 168 81445 0 79353 127 20 107 112 0 357 10 vmsppl 368 615 0 595 2 0 2 2 0 8 0 pdppl 4096 1239 0 1195 6 0 6 6 0 8 0 pvpl 32 221385 0 201704 200 3 197 197 0 265 35 pmappl 232 615 0 595 3 1 2 2 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 284 0 6 8 0 8 8 0 8 0 ddb{0}> machine ddbcpu 0 Invalid cpu 0 ddb{0}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823ebefd) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd806444fd00,244,22c,2) at m_copym+0x583 sys/kern/uipc_mbuf.c:695 tcp_output(ffff800000ada100) at tcp_output+0x15ba sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd806eaf3968,9,fffffd806444fc00,0,0,ffff800020e41390) at tcp_usrreq+0xa55 sosend(fffffd806eaf3968,0,ffff800020e63808,0,0,80) at sosend+0x671 sys/kern/uipc_socket.c:555 dofilewritev(ffff800020e41390,4,ffff800020e63808,0,ffff800020e638f0) at dofilewritev+0x1b6 sys/kern/sys_generic.c:365 sys_write(ffff800020e41390,ffff800020e638a0,ffff800020e638f0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff800020e63970) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff800020e63970) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff6ae0, count: -10 ddb{0}> machine ddbcpu 1