panic: kernel diagnostic assertion "len >= 0 && !M_READONLY(m)" failed: file "/syzkaller/managers/main/kernel/sys/kern/uipc_mbuf.c", line 1384 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *326383 49311 0 0 0x4000000 0 syz-executor.6 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:440 panic(ffffffff8254c243) at panic+0x161 sys/kern/subr_prf.c:202 __assert(ffffffff825bc0e6,ffffffff825cea0d,568,ffffffff8255f800) at __assert+0x25 sys/kern/subr_prf.c:161 m_align(fffffd807ad3f000,ffffffc0) at m_align+0x1a0 sys/kern/uipc_mbuf.c:1385 bpf_movein(ffff80002b389bf0,ffff800000c0ca00,ffff80002b389958,ffff80002b389858) at bpf_movein+0x25e sys/net/bpf.c:228 bpfwrite(91700,ffff80002b389bf0,1) at bpfwrite+0x128 sys/net/bpf.c:648 spec_write(ffff80002b389a50) at spec_write+0xcb sys/kern/spec_vnops.c:309 VOP_WRITE(fffffd807b3dc880,ffff80002b389bf0,1,fffffd807f7d8720) at VOP_WRITE+0xbf sys/kern/vfs_vops.c:245 vn_write(fffffd805b7e05b0,ffff80002b389bf0,1) at vn_write+0x19c sys/kern/vfs_vnops.c:414 dofilewritev(ffff80002cdbd510,5,ffff80002b389bf0,1,ffff80002b389cf0) at dofilewritev+0x19c sys/kern/sys_generic.c:381 sys_pad_pwrite(ffff80002cdbd510,ffff80002b389c98,ffff80002b389cf0) at sys_pad_pwrite+0x92 sys_pwrite sys/kern/vfs_syscalls.c:3354 [inline] sys_pad_pwrite(ffff80002cdbd510,ffff80002b389c98,ffff80002b389cf0) at sys_pad_pwrite+0x92 sys/kern/vfs_syscalls.c:3426 syscall(ffff80002b389d60) at syscall+0x44e sys/arch/amd64/amd64/trap.c:585 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x3032a075df0, count: 2 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> ddb> set $lines = 0 ddb> set $maxwidth = 0 ddb> show panic *cpu0: kernel diagnostic assertion "len >= 0 && !M_READONLY(m)" failed: file "/syzkaller/managers/main/kernel/sys/kern/uipc_mbuf.c", line 1384 ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:440 panic(ffffffff8254c243) at panic+0x161 sys/kern/subr_prf.c:202 __assert(ffffffff825bc0e6,ffffffff825cea0d,568,ffffffff8255f800) at __assert+0x25 sys/kern/subr_prf.c:161 m_align(fffffd807ad3f000,ffffffc0) at m_align+0x1a0 sys/kern/uipc_mbuf.c:1385 bpf_movein(ffff80002b389bf0,ffff800000c0ca00,ffff80002b389958,ffff80002b389858) at bpf_movein+0x25e sys/net/bpf.c:228 bpfwrite(91700,ffff80002b389bf0,1) at bpfwrite+0x128 sys/net/bpf.c:648 spec_write(ffff80002b389a50) at spec_write+0xcb sys/kern/spec_vnops.c:309 VOP_WRITE(fffffd807b3dc880,ffff80002b389bf0,1,fffffd807f7d8720) at VOP_WRITE+0xbf sys/kern/vfs_vops.c:245 vn_write(fffffd805b7e05b0,ffff80002b389bf0,1) at vn_write+0x19c sys/kern/vfs_vnops.c:414 dofilewritev(ffff80002cdbd510,5,ffff80002b389bf0,1,ffff80002b389cf0) at dofilewritev+0x19c sys/kern/sys_generic.c:381 sys_pad_pwrite(ffff80002cdbd510,ffff80002b389c98,ffff80002b389cf0) at sys_pad_pwrite+0x92 sys_pwrite sys/kern/vfs_syscalls.c:3354 [inline] sys_pad_pwrite(ffff80002cdbd510,ffff80002b389c98,ffff80002b389cf0) at sys_pad_pwrite+0x92 sys/kern/vfs_syscalls.c:3426 syscall(ffff80002b389d60) at syscall+0x44e sys/arch/amd64/amd64/trap.c:585 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x3032a075df0, count: -13 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80002b389680 rbx 0 rdx 0xffff800000c2a7c0 rcx 0 rax 0xffff80002cdbd510 r8 0 r9 0x8080808080808080 r10 0xcea34f86d1f3a4b1 r11 0xb6a8495e35ed7f0a r12 0 r13 0xffffffc0 r14 0 r15 0x1 rip 0xffffffff811d4e78 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80002b389670 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (syz-executor.6) pid=326383 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=84, nice=20 forw=0xffffffffffffffff, list=0xffff80002cdbcfd0,0xffff80002169ed38 process=0xffff800028d4efc8 user=0xffff80002b384000, vmspace=0xfffffd8068487770 estcpu=34, cpticks=1, pctcpu=0.0 user=0, sys=1, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 31651 154768 92689 0 2 0 syz-executor.0 31651 40797 92689 0 3 0x4000080 fsleep syz-executor.0 31651 369115 92689 0 3 0x4000080 fsleep syz-executor.0 60431 66467 33695 0 2 0 syz-executor.4 60431 149107 33695 0 3 0x4000080 fsleep syz-executor.4 80263 414535 21318 0 2 0 syz-executor.2 80263 136394 21318 0 3 0x4000080 fsleep syz-executor.2 49311 482850 79924 0 2 0 syz-executor.6 *49311 326383 79924 0 7 0x4000000 syz-executor.6 36017 205665 20308 0 2 0 syz-executor.5 36017 241098 20308 0 3 0x4000080 fsleep syz-executor.5 49999 98827 24235 0 2 0 syz-executor.7 49999 283310 24235 0 3 0x4000080 fsleep syz-executor.7 79924 431839 56711 0 2 0x482 syz-executor.6 24235 433418 56711 0 2 0x482 syz-executor.7 79047 403692 1 0 3 0x100083 ttyin getty 14217 311145 56711 0 2 0x482 syz-executor.1 61471 128680 56711 0 2 0x482 syz-executor.3 33695 318475 56711 0 2 0x482 syz-executor.4 20308 15733 56711 0 2 0x482 syz-executor.5 59435 228974 0 0 3 0x14200 bored sosplice 92689 264584 56711 0 3 0x82 nanoslp syz-executor.0 21318 99203 56711 0 2 0x482 syz-executor.2 56711 432517 54307 0 3 0x82 thrsleep syz-fuzzer 56711 70785 54307 0 3 0x4000082 thrsleep syz-fuzzer 56711 502534 54307 0 3 0x4000082 thrsleep syz-fuzzer 56711 145878 54307 0 3 0x4000082 thrsleep syz-fuzzer 56711 424056 54307 0 3 0x4000082 kqread syz-fuzzer 56711 421632 54307 0 3 0x4000082 thrsleep syz-fuzzer 56711 415457 54307 0 3 0x4000082 thrsleep syz-fuzzer 56711 6282 54307 0 3 0x4000082 thrsleep syz-fuzzer 56711 403224 54307 0 3 0x4000082 thrsleep syz-fuzzer 54307 233068 41501 0 3 0x10008a sigsusp ksh 41501 39323 28056 0 3 0x9a kqread sshd 28056 192053 1 0 3 0x88 kqread sshd 37600 118362 55892 73 3 0x100090 kqread syslogd 55892 317889 1 0 3 0x100082 netio syslogd 15379 434177 1 0 3 0x100080 kqread resolvd 85461 15450 87702 77 3 0x100092 kqread dhcpleased 80102 380943 87702 77 3 0x100092 kqread dhcpleased 87702 106832 1 0 3 0x80 kqread dhcpleased 13327 184208 0 0 3 0x14200 bored smr 64008 226564 0 0 2 0x14200 zerothread 70016 20713 0 0 3 0x14200 aiodoned aiodoned 78746 169817 0 0 3 0x14200 syncer update 64661 184830 0 0 3 0x14200 cleaner cleaner 1593 268233 0 0 3 0x14200 reaper reaper 7153 479020 0 0 3 0x14200 pgdaemon pagedaemon 78565 304549 0 0 3 0x14200 bored viomb 30831 111713 0 0 3 0x40014200 acpi0 acpi0 83510 347689 0 0 3 0x14200 bored softnet 56476 342491 0 0 3 0x14200 bored systqmp 72360 494399 0 0 3 0x14200 bored systq 20443 206594 0 0 2 0x40014200 softclock 80460 247038 0 0 3 0x40014200 idle0 1 290013 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb> show all locks No such command ddb> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 10209 6933K 19211K 78643K 22126 0 pcb 13 18K 20K 78643K 573 0 rtable 232 11K 13K 78643K 1311 0 ifaddr 85 18K 19K 78643K 418 0 counters 27 17K 17K 78643K 61 0 ioctlops 0 0K 4K 78643K 810 0 iov 0 0K 28K 78643K 218 0 mount 1 1K 1K 78643K 1 0 log 0 0K 0K 78643K 4 0 vnodes 1336 83K 84K 78643K 4483 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 20 0 VM map 2 0K 0K 78643K 2 0 sem 12 0K 0K 78643K 583 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12548 0 file desc 16 57K 77K 78643K 3005 0 sigio 0 0K 0K 78643K 111 0 proc 60 55K 71K 78643K 900 0 subproc 104 6K 6K 78643K 273 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 100 0 in_multi 88 6K 6K 78643K 377 0 ether_multi 1 0K 0K 78643K 26 0 mrt 0 0K 0K 78643K 4 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 79 360K 360K 78643K 79 0 exec 0 0K 2K 78643K 1306 0 tdb 3 0K 0K 78643K 3 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 371 311K 902K 78643K 37865 0 UVM aobj 100 8K 8K 78643K 103 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 127 0 NDP 11 0K 2K 78643K 103 0 temp 129 4703K 4771K 78643K 30716 0 kqueue 12 18K 28K 78643K 226 0 SYN cache 2 16K 16K 78643K 2 0 ddb> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle rtpcb 120 218 0 215 3 2 1 2 0 8 0 rtentry 112 377 0 281 4 0 4 4 0 8 0 unpcb 136 1516 0 1501 19 18 1 6 0 8 0 syncache 296 19 0 19 3 3 0 1 0 8 0 tcpqe 32 67 0 67 1 1 0 1 0 8 0 tcpcb 736 1195 0 1190 47 37 10 14 0 8 9 arp 88 51 0 33 1 0 1 1 0 8 0 ipq 40 5 0 4 2 1 1 1 0 8 0 ipqe 40 16 0 15 2 1 1 1 0 8 0 inpcb 304 3055 0 3048 47 40 7 11 0 8 6 ip6q 72 8 0 7 2 1 1 1 0 8 0 ip6af 40 14 0 13 2 1 1 1 0 8 0 nd6 48 81 0 59 1 0 1 1 0 8 0 pkpcb 40 10 0 10 2 2 0 1 0 8 0 kcovpl 48 21 0 13 1 0 1 1 0 8 0 ppxss 1152 9 0 9 2 2 0 1 0 8 0 pfstscr 40 3 0 2 1 0 1 1 0 8 0 pfrktable 1344 102 0 93 3 2 1 2 0 8 0 pfstitem 24 2 0 0 1 0 1 1 0 8 0 pfstkey 112 14 0 12 2 1 1 1 0 8 0 pfstate 320 7 0 6 2 1 1 1 0 8 0 pfrule 1360 93 0 73 2 0 2 2 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 1600 0 1197 32 5 27 30 0 8 0 art_table 32 1601 0 1197 4 0 4 4 0 8 0 art_node 16 376 0 291 1 0 1 1 0 8 0 sysvmsgpl 40 4 0 2 1 0 1 1 0 8 0 semupl 112 6 0 6 1 1 0 1 0 8 0 semapl 112 514 0 504 1 0 1 1 0 8 0 shmpl 112 100 0 3 3 0 3 3 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 5535 0 4107 90 0 90 90 0 8 0 ffsino 240 5535 0 4107 85 0 85 85 0 8 0 nchpl 144 9440 0 7814 62 0 62 62 0 8 0 uvmvnodes 80 5926 0 0 121 0 121 121 0 8 0 vnodes 224 5926 0 0 349 0 349 349 0 8 0 namei 1024 36192 0 36192 4 3 1 2 0 8 1 vcpupl 1984 83 0 0 11 0 11 11 0 8 0 vmpool 528 86 0 3 6 0 6 6 0 8 0 pfiaddrpl 120 40 0 26 3 2 1 1 0 8 0 scsiplug 72 3 0 3 1 1 0 1 0 8 0 scxspl 216 26933 0 26933 13 12 1 8 0 8 1 plimitpl 152 394 0 380 1 0 1 1 0 8 0 sigapl 424 3263 0 3222 6 1 5 6 0 8 0 futexpl 64 30937 0 30931 2 1 1 1 0 8 0 knotepl 120 32221 0 32141 6 3 3 6 0 8 0 kqueuepl 184 632 0 623 13 11 2 4 0 8 1 pipepl 304 824 0 731 26 18 8 8 0 8 0 fdescpl 432 3249 0 3222 4 0 4 4 0 8 0 filepl 120 22633 0 22257 43 31 12 15 0 8 0 lockfpl 104 989 0 987 4 3 1 2 0 8 0 lockfspl 48 306 0 304 1 0 1 1 0 8 0 sessionpl 144 37 0 21 1 0 1 1 0 8 0 pgrppl 48 106 0 90 1 0 1 1 0 8 0 ucredpl 96 2958 0 2948 1 0 1 1 0 8 0 zombiepl 144 3222 0 3220 3 2 1 1 0 8 0 processpl 1000 3263 0 3220 6 0 6 6 0 8 0 procpl 672 7798 0 7740 9 3 6 7 0 8 0 sosppl 168 14 0 14 4 4 0 1 0 8 0 sockpl 448 4801 0 4776 83 74 9 19 0 8 6 mcl64k 65536 127 0 127 7 7 0 1 0 8 0 mcl16k 16384 24 0 24 5 5 0 1 0 8 0 mcl12k 12288 109 0 109 9 8 1 1 0 8 1 mcl9k 9216 88 0 88 7 6 1 1 0 8 1 mcl8k 8192 334 0 334 6 5 1 1 0 8 1 mcl4k 4096 394 0 394 4 3 1 1 0 8 1 mcl2k2 2112 38 0 38 9 8 1 1 0 8 1 mcl2k 2048 82381 0 82167 37 8 29 29 0 8 0 mtagpl 96 3085 0 2036 29 2 27 27 0 8 0 mbufpl 256 153621 0 152344 91 8 83 83 0 8 0 bufpl 288 8152 0 1745 458 0 458 458 0 8 0 anonpl 24 873184 0 854054 152 28 124 138 0 188 0 amapchunkpl 152 648189 0 647409 770 593 177 663 0 158 144 amappl16 200 9307 0 8577 76 34 42 51 0 8 2 amappl15 192 520 0 512 1 0 1 1 0 8 0 amappl14 184 153 0 147 1 0 1 1 0 8 0 amappl13 176 365 0 362 1 0 1 1 0 8 0 amappl12 168 443 0 437 2 1 1 1 0 8 0 amappl11 160 229 0 218 1 0 1 1 0 8 0 amappl10 152 541 0 538 1 0 1 1 0 8 0 amappl9 144 1287 0 1280 1 0 1 1 0 8 0 amappl8 136 1041 0 968 3 0 3 3 0 8 0 amappl7 128 329 0 319 1 0 1 1 0 8 0 amappl6 120 1051 0 1028 2 1 1 2 0 8 0 amappl5 112 3232 0 3215 1 0 1 1 0 8 0 amappl4 104 1408 0 1378 2 1 1 2 0 8 0 amappl3 96 1009 0 995 1 0 1 1 0 8 0 amappl2 88 1000 0 949 3 1 2 3 0 8 0 amappl1 80 60273 0 59715 18 5 13 18 0 8 0 amappl 88 37113 0 36864 7 0 7 7 0 92 0 dma4096 4096 1 0 1 1 1 0 1 0 8 0 dma1024 1024 1 0 0 1 0 1 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 72 102 0 3 2 0 2 2 0 8 0 uaddrrnd 24 3335 0 3225 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 3335 0 3225 1 0 1 1 0 8 0 vmmpekpl 168 26930 0 26877 3 0 3 3 0 8 0 vmmpepl 168 302645 0 299933 195 69 126 143 0 357 0 vmsppl 272 3334 0 3225 10 2 8 8 0 8 0 rwobjpl 24 78131 0 70412 48 1 47 48 0 8 0 pdppl 4096 6676 0 6533 356 209 147 147 0 8 4 pvpl 32 1560008 0 1536598 312 111 201 252 0 265 6 pmappl 216 3334 0 3225 7 0 7 7 0 8 0 extentpl 40 58 0 38 1 0 1 1 0 8 0 phpool 112 1324 0 368 28 0 28 28 0 8 0 ddb> machine ddbcpu 0 No such command ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:440 panic(ffffffff8254c243) at panic+0x161 sys/kern/subr_prf.c:202 __assert(ffffffff825bc0e6,ffffffff825cea0d,568,ffffffff8255f800) at __assert+0x25 sys/kern/subr_prf.c:161 m_align(fffffd807ad3f000,ffffffc0) at m_align+0x1a0 sys/kern/uipc_mbuf.c:1385 bpf_movein(ffff80002b389bf0,ffff800000c0ca00,ffff80002b389958,ffff80002b389858) at bpf_movein+0x25e sys/net/bpf.c:228 bpfwrite(91700,ffff80002b389bf0,1) at bpfwrite+0x128 sys/net/bpf.c:648 spec_write(ffff80002b389a50) at spec_write+0xcb sys/kern/spec_vnops.c:309 VOP_WRITE(fffffd807b3dc880,ffff80002b389bf0,1,fffffd807f7d8720) at VOP_WRITE+0xbf sys/kern/vfs_vops.c:245 vn_write(fffffd805b7e05b0,ffff80002b389bf0,1) at vn_write+0x19c sys/kern/vfs_vnops.c:414 dofilewritev(ffff80002cdbd510,5,ffff80002b389bf0,1,ffff80002b389cf0) at dofilewritev+0x19c sys/kern/sys_generic.c:381 sys_pad_pwrite(ffff80002cdbd510,ffff80002b389c98,ffff80002b389cf0) at sys_pad_pwrite+0x92 sys_pwrite sys/kern/vfs_syscalls.c:3354 [inline] sys_pad_pwrite(ffff80002cdbd510,ffff80002b389c98,ffff80002b389cf0) at sys_pad_pwrite+0x92 sys/kern/vfs_syscalls.c:3426 syscall(ffff80002b389d60) at syscall+0x44e sys/arch/amd64/amd64/trap.c:585 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x3032a075df0, count: -13 ddb> machine ddbcpu 1 No such command ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:440 panic(ffffffff8254c243) at panic+0x161 sys/kern/subr_prf.c:202 __assert(ffffffff825bc0e6,ffffffff825cea0d,568,ffffffff8255f800) at __assert+0x25 sys/kern/subr_prf.c:161 m_align(fffffd807ad3f000,ffffffc0) at m_align+0x1a0 sys/kern/uipc_mbuf.c:1385 bpf_movein(ffff80002b389bf0,ffff800000c0ca00,ffff80002b389958,ffff80002b389858) at bpf_movein+0x25e sys/net/bpf.c:228 bpfwrite(91700,ffff80002b389bf0,1) at bpfwrite+0x128 sys/net/bpf.c:648 spec_write(ffff80002b389a50) at spec_write+0xcb sys/kern/spec_vnops.c:309 VOP_WRITE(fffffd807b3dc880,ffff80002b389bf0,1,fffffd807f7d8720) at VOP_WRITE+0xbf sys/kern/vfs_vops.c:245 vn_write(fffffd805b7e05b0,ffff80002b389bf0,1) at vn_write+0x19c sys/kern/vfs_vnops.c:414 dofilewritev(ffff80002cdbd510,5,ffff80002b389bf0,1,ffff80002b389cf0) at dofilewritev+0x19c sys/kern/sys_generic.c:381 sys_pad_pwrite(ffff80002cdbd510,ffff80002b389c98,ffff80002b389cf0) at sys_pad_pwrite+0x92 sys_pwrite sys/kern/vfs_syscalls.c:3354 [inline] sys_pad_pwrite(ffff80002cdbd510,ffff80002b389c98,ffff80002b389cf0) at sys_pad_pwrite+0x92 sys/kern/vfs_syscalls.c:3426 syscall(ffff80002b389d60) at syscall+0x44e sys/arch/amd64/amd64/trap.c:585 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x3032a075df0, count: -13