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 *496006 68158 0 0 0x4000000 0 syz-executor.1 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:440 panic(ffffffff82547276) at panic+0x161 sys/kern/subr_prf.c:202 __assert(ffffffff825bae63,ffffffff825cabcb,568,ffffffff8255b781) at __assert+0x25 sys/kern/subr_prf.c:161 m_align(fffffd8073225c00,ffffffc1) at m_align+0x1a0 sys/kern/uipc_mbuf.c:1385 bpf_movein(ffff8000216bb418,ffff800000c5c800,ffff8000216bb178,ffff8000216bb078) at bpf_movein+0x25e sys/net/bpf.c:228 bpfwrite(41700,ffff8000216bb418,11) at bpfwrite+0x128 sys/net/bpf.c:644 spec_write(ffff8000216bb270) at spec_write+0xcb sys/kern/spec_vnops.c:309 VOP_WRITE(fffffd8063da5888,ffff8000216bb418,11,fffffd807f7d8b40) at VOP_WRITE+0xbf sys/kern/vfs_vops.c:245 vn_write(fffffd8067bcbd28,ffff8000216bb418,0) at vn_write+0x152 sys/kern/vfs_vnops.c:414 dofilewritev(ffff80002e7e7a50,3,ffff8000216bb418,0,ffff8000216bb510) at dofilewritev+0x19c sys/kern/sys_generic.c:381 sys_write(ffff80002e7e7a50,ffff8000216bb4b8,ffff8000216bb510) at sys_write+0x83 sys/kern/sys_generic.c:301 syscall(ffff8000216bb580) at syscall+0x44e sys/arch/amd64/amd64/trap.c:585 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xea2dce8fe40, 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(ffffffff82547276) at panic+0x161 sys/kern/subr_prf.c:202 __assert(ffffffff825bae63,ffffffff825cabcb,568,ffffffff8255b781) at __assert+0x25 sys/kern/subr_prf.c:161 m_align(fffffd8073225c00,ffffffc1) at m_align+0x1a0 sys/kern/uipc_mbuf.c:1385 bpf_movein(ffff8000216bb418,ffff800000c5c800,ffff8000216bb178,ffff8000216bb078) at bpf_movein+0x25e sys/net/bpf.c:228 bpfwrite(41700,ffff8000216bb418,11) at bpfwrite+0x128 sys/net/bpf.c:644 spec_write(ffff8000216bb270) at spec_write+0xcb sys/kern/spec_vnops.c:309 VOP_WRITE(fffffd8063da5888,ffff8000216bb418,11,fffffd807f7d8b40) at VOP_WRITE+0xbf sys/kern/vfs_vops.c:245 vn_write(fffffd8067bcbd28,ffff8000216bb418,0) at vn_write+0x152 sys/kern/vfs_vnops.c:414 dofilewritev(ffff80002e7e7a50,3,ffff8000216bb418,0,ffff8000216bb510) at dofilewritev+0x19c sys/kern/sys_generic.c:381 sys_write(ffff80002e7e7a50,ffff8000216bb4b8,ffff8000216bb510) at sys_write+0x83 sys/kern/sys_generic.c:301 syscall(ffff8000216bb580) at syscall+0x44e sys/arch/amd64/amd64/trap.c:585 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xea2dce8fe40, count: -13 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff8000216baea0 rbx 0x8 rdx 0xffff800000bf0c00 rcx 0 rax 0xffff80002e7e7a50 r8 0 r9 0x8080808080808080 r10 0xe2125c370486b471 r11 0x87c9f5d9b3deebfa r12 0 r13 0xffffffc1 r14 0 r15 0x1 rip 0xffffffff81e942b8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff8000216bae90 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (syz-executor.1) pid=496006 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=83, nice=20 forw=0xffffffffffffffff, list=0xffff80002e7e67f0,0xffff80002e7e7d00 process=0xffff8000216207e8 user=0xffff8000216b6000, vmspace=0xfffffd80761dc340 estcpu=33, cpticks=1, pctcpu=0.0 user=0, sys=1, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 68158 471880 34723 0 2 0 syz-executor.1 *68158 496006 34723 0 7 0x4000000 syz-executor.1 45333 397869 70707 0 2 0 syz-executor.3 45333 214221 70707 0 3 0x4000080 fsleep syz-executor.3 88843 472144 78994 0 3 0x80 nanoslp syz-executor.2 88843 239154 78994 0 3 0x4000080 fsleep syz-executor.2 88843 269971 78994 0 3 0x4000080 fsleep syz-executor.2 30823 340782 30883 0 2 0 syz-executor.0 30823 17067 30883 0 3 0x4000080 fsleep syz-executor.0 30823 265436 30883 0 3 0x4000080 fsleep syz-executor.0 30823 520449 30883 0 3 0x4000080 fsleep syz-executor.0 15183 411608 74819 0 2 0 syz-executor.6 15183 7863 74819 0 3 0x4000080 fsleep syz-executor.6 96468 35324 66236 0 2 0x82000 syz-executor.7 96468 313910 66236 0 4 0x4082000 syz-executor.7 96468 228401 66236 0 3 0x4002000 suspend syz-executor.7 96468 496025 66236 0 4 0x4082000 syz-executor.7 64354 483054 32278 0 2 0x482 syz-executor.5 66236 175063 32278 0 2 0x482 syz-executor.7 30883 511108 32278 0 2 0x482 syz-executor.0 78994 320071 32278 0 2 0x482 syz-executor.2 74819 508181 32278 0 3 0x82 nanoslp syz-executor.6 70707 488974 32278 0 3 0x82 nanoslp syz-executor.3 494 465966 1 0 3 0x100083 ttyin getty 34723 182188 32278 0 3 0x82 nanoslp syz-executor.1 90908 444442 0 0 3 0x14280 nfsidl nfsio 9621 400868 0 0 3 0x14280 nfsidl nfsio 40038 260478 0 0 3 0x14280 nfsidl nfsio 30790 67226 0 0 3 0x14280 nfsidl nfsio 19386 421449 0 0 3 0x14280 nfsidl nfsio 17253 410149 0 0 3 0x14280 nfsidl nfsio 95526 457361 0 0 3 0x14280 nfsidl nfsio 15759 392336 0 0 3 0x14280 nfsidl nfsio 64347 449476 0 0 3 0x14280 nfsidl nfsio 36401 456995 0 0 3 0x14280 nfsidl nfsio 41868 236542 0 0 3 0x14280 nfsidl nfsio 42157 460631 0 0 3 0x14280 nfsidl nfsio 37224 72491 0 0 3 0x14280 nfsidl nfsio 45288 30296 0 0 3 0x14280 nfsidl nfsio 36640 281776 0 0 3 0x14280 nfsidl nfsio 77405 186123 0 0 3 0x14280 nfsidl nfsio 28893 223773 0 0 3 0x14280 nfsidl nfsio 24444 296330 0 0 3 0x14280 nfsidl nfsio 5726 219111 0 0 3 0x14280 nfsidl nfsio 62115 356475 0 0 3 0x14280 nfsidl nfsio 70261 306116 0 0 3 0x14200 bored sosplice 32278 406132 71800 0 3 0x82 thrsleep syz-fuzzer 32278 183569 71800 0 3 0x4000082 nanoslp syz-fuzzer 32278 3514 71800 0 3 0x4000082 thrsleep syz-fuzzer 32278 219425 71800 0 3 0x4000082 kqread syz-fuzzer 32278 330985 71800 0 3 0x4000082 thrsleep syz-fuzzer 32278 260576 71800 0 2 0x4000002 syz-fuzzer 32278 438434 71800 0 3 0x4000082 thrsleep syz-fuzzer 32278 477322 71800 0 3 0x4000082 thrsleep syz-fuzzer 32278 136078 71800 0 3 0x4000082 thrsleep syz-fuzzer 71800 19529 91362 0 3 0x10008a sigsusp ksh 91362 143915 43549 0 3 0x9a kqread sshd 43549 225990 1 0 3 0x88 kqread sshd 68925 330891 68807 73 3 0x100090 kqread syslogd 68807 316600 1 0 3 0x100082 netio syslogd 96180 384395 1 0 3 0x100080 kqread resolvd 67642 346295 7409 77 3 0x100092 kqread dhcpleased 36451 440802 7409 77 3 0x100092 kqread dhcpleased 7409 516223 1 0 3 0x80 kqread dhcpleased 66530 351488 0 0 3 0x14200 bored smr 80290 296523 0 0 2 0x14200 zerothread 29227 43802 0 0 3 0x14200 aiodoned aiodoned 23627 484418 0 0 3 0x14200 syncer update 32384 414597 0 0 3 0x14200 cleaner cleaner 48652 418007 0 0 3 0x14200 reaper reaper 27344 94697 0 0 3 0x14200 pgdaemon pagedaemon 52524 292332 0 0 3 0x14200 bored viomb 62359 115603 0 0 3 0x40014200 acpi0 acpi0 69885 97997 0 0 3 0x14200 bored softnet 38957 295220 0 0 3 0x14200 bored systqmp 39033 139034 0 0 3 0x14200 bored systq 37333 85608 0 0 3 0x40014200 bored softclock 86839 435093 0 0 3 0x40014200 idle0 1 100101 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 10215 6628K 7574K 78643K 34779 0 pcb 13 16K 18K 78643K 962 0 rtable 210 14K 15K 78643K 1934 0 ifaddr 79 18K 19K 78643K 574 0 sysctl 3 1K 1K 78643K 3 0 counters 26 17K 17K 78643K 113 0 ioctlops 0 0K 4K 78643K 1434 0 iov 0 0K 26K 78643K 715 0 mount 1 1K 1K 78643K 1 0 log 0 0K 0K 78643K 4 0 vnodes 1439 90K 90K 78643K 8804 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 82 0 VM map 2 0K 0K 78643K 2 0 sem 12 1K 1K 78643K 445 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12548 0 file desc 15 53K 85K 78643K 6739 0 sigio 0 0K 0K 78643K 41 0 proc 58 55K 71K 78643K 1607 0 subproc 91 5K 6K 78643K 559 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 346 0 in_multi 88 5K 7K 78643K 735 0 ether_multi 1 0K 0K 78643K 85 0 mrt 1 0K 0K 78643K 27 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 241 1076K 1076K 78643K 241 0 exec 0 0K 2K 78643K 2441 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 410 358K 1006K 78643K 81461 0 UVM aobj 131 7K 7K 78643K 138 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 378 0 NDP 11 0K 1K 78643K 193 0 temp 121 4694K 6231K 78643K 50455 0 kqueue 13 20K 26K 78643K 517 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 120 479 0 476 7 6 1 3 0 8 0 rtentry 112 591 0 499 4 1 3 4 0 8 0 unpcb 136 5003 0 4990 48 46 2 9 0 8 1 syncache 296 30 0 30 7 7 0 1 0 8 0 sackhl 24 1 0 1 1 1 0 1 0 8 0 tcpqe 32 10 0 10 5 5 0 1 0 8 0 tcpcb 736 2096 0 2091 75 74 1 15 0 8 0 arp 88 97 0 81 1 0 1 1 0 8 0 ipq 40 85 0 85 8 7 1 1 0 8 1 ipqe 40 3008 0 3008 8 7 1 1 0 8 1 inpcb 304 5598 0 5590 71 67 4 12 0 8 3 rttmr 72 3 0 3 1 1 0 1 0 8 0 ip6q 72 1 0 1 1 1 0 1 0 8 0 nd6 48 143 0 122 1 0 1 1 0 8 0 pkpcb 40 7 0 7 2 2 0 1 0 8 0 kcovpl 48 43 0 36 1 0 1 1 0 8 0 ppxss 1152 27 0 27 7 7 0 1 0 8 0 pftag 88 2 0 0 1 0 1 1 0 8 0 pfrule 1360 4 0 4 1 1 0 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 2643 0 2236 45 16 29 29 0 8 0 art_table 32 2644 0 2236 4 0 4 4 0 8 0 art_node 16 585 0 505 1 0 1 1 0 8 0 sysvmsgpl 40 121 0 107 1 0 1 1 0 8 0 semupl 112 5 0 5 1 1 0 1 0 8 0 semapl 112 438 0 428 1 0 1 1 0 8 0 shmpl 112 135 0 7 4 0 4 4 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 10365 0 8910 92 0 92 92 0 8 0 ffsino 240 10365 0 8910 86 0 86 86 0 8 0 nchpl 144 20030 0 18405 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 75932 0 75932 9 8 1 2 0 8 1 vcpupl 1984 18 0 0 3 0 3 3 0 8 0 vmpool 528 25 0 7 2 0 2 2 0 8 0 scxspl 216 65011 0 65011 19 18 1 8 0 8 1 plimitpl 152 550 0 535 1 0 1 1 0 8 0 sigapl 424 6974 0 6914 10 2 8 8 0 8 0 futexpl 64 64505 0 64498 7 6 1 1 0 8 0 knotepl 120 68370 0 68295 18 15 3 10 0 8 0 kqueuepl 184 1461 0 1452 20 19 1 4 0 8 0 pipepl 304 1765 0 1740 42 39 3 12 0 8 0 fdescpl 432 6938 0 6912 4 0 4 4 0 8 0 filepl 120 51428 0 51200 77 66 11 16 0 8 3 lockfpl 104 1795 0 1793 4 3 1 2 0 8 0 lockfspl 48 380 0 378 1 0 1 1 0 8 0 sessionpl 144 60 0 45 1 0 1 1 0 8 0 pgrppl 48 185 0 170 1 0 1 1 0 8 0 ucredpl 96 7299 0 7289 1 0 1 1 0 8 0 zombiepl 144 6914 0 6913 2 1 1 1 0 8 0 processpl 1000 6974 0 6913 9 0 9 9 0 8 0 procpl 672 16636 0 16556 24 16 8 9 0 8 0 sosppl 168 48 0 48 8 8 0 1 0 8 0 sockpl 448 11095 0 11067 223 216 7 31 0 8 3 mcl64k 65536 297 0 297 19 18 1 1 0 8 1 mcl16k 16384 63 0 63 14 13 1 1 0 8 1 mcl12k 12288 175 0 175 13 12 1 1 0 8 1 mcl9k 9216 99 0 99 18 17 1 1 0 8 1 mcl8k 8192 475 0 475 13 12 1 1 0 8 1 mcl4k 4096 674 0 674 13 12 1 1 0 8 1 mcl2k2 2112 56 0 56 18 17 1 1 0 8 1 mcl2k 2048 88504 0 88434 48 34 14 30 0 8 0 mtagpl 96 6677 0 6259 61 49 12 41 0 8 0 mbufpl 256 208309 0 207672 654 607 47 561 0 8 0 bufpl 288 15704 0 9296 459 0 459 459 0 8 0 anonpl 24 1935100 0 1917064 273 140 133 178 0 188 0 amapchunkpl 152 272136 0 271353 1203 1065 138 662 0 158 106 amappl16 200 20392 0 19662 112 69 43 52 0 8 0 amappl15 192 2037 0 2029 1 0 1 1 0 8 0 amappl14 184 791 0 786 1 0 1 1 0 8 0 amappl13 176 432 0 430 1 0 1 1 0 8 0 amappl12 168 1096 0 1092 2 1 1 1 0 8 0 amappl11 160 399 0 384 1 0 1 1 0 8 0 amappl10 152 732 0 727 1 0 1 1 0 8 0 amappl9 144 1923 0 1920 1 0 1 1 0 8 0 amappl8 136 1983 0 1881 4 0 4 4 0 8 0 amappl7 128 917 0 907 1 0 1 1 0 8 0 amappl6 120 1761 0 1741 2 1 1 2 0 8 0 amappl5 112 6016 0 5997 1 0 1 1 0 8 0 amappl4 104 2962 0 2925 2 0 2 2 0 8 0 amappl3 96 1820 0 1808 1 0 1 1 0 8 0 amappl2 88 1485 0 1428 3 1 2 3 0 8 0 amappl1 80 123747 0 123185 18 5 13 18 0 8 0 amappl 88 80272 0 80009 8 1 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 72 137 0 7 3 0 3 3 0 8 0 uaddrrnd 24 6963 0 6919 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 6963 0 6919 1 0 1 1 0 8 0 vmmpekpl 168 51615 0 51556 4 0 4 4 0 8 0 vmmpepl 168 641733 0 639072 267 126 141 147 0 357 5 vmsppl 272 6962 0 6919 9 5 4 4 0 8 0 rwobjpl 24 154616 0 146828 49 0 49 49 0 8 0 pdppl 4096 13932 0 13856 446 364 82 82 0 8 6 pvpl 32 3372258 0 3350484 506 293 213 307 0 265 9 pmappl 216 6962 0 6919 4 1 3 3 0 8 0 extentpl 40 58 0 38 1 0 1 1 0 8 0 phpool 112 2213 0 1382 39 11 28 39 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(ffffffff82547276) at panic+0x161 sys/kern/subr_prf.c:202 __assert(ffffffff825bae63,ffffffff825cabcb,568,ffffffff8255b781) at __assert+0x25 sys/kern/subr_prf.c:161 m_align(fffffd8073225c00,ffffffc1) at m_align+0x1a0 sys/kern/uipc_mbuf.c:1385 bpf_movein(ffff8000216bb418,ffff800000c5c800,ffff8000216bb178,ffff8000216bb078) at bpf_movein+0x25e sys/net/bpf.c:228 bpfwrite(41700,ffff8000216bb418,11) at bpfwrite+0x128 sys/net/bpf.c:644 spec_write(ffff8000216bb270) at spec_write+0xcb sys/kern/spec_vnops.c:309 VOP_WRITE(fffffd8063da5888,ffff8000216bb418,11,fffffd807f7d8b40) at VOP_WRITE+0xbf sys/kern/vfs_vops.c:245 vn_write(fffffd8067bcbd28,ffff8000216bb418,0) at vn_write+0x152 sys/kern/vfs_vnops.c:414 dofilewritev(ffff80002e7e7a50,3,ffff8000216bb418,0,ffff8000216bb510) at dofilewritev+0x19c sys/kern/sys_generic.c:381 sys_write(ffff80002e7e7a50,ffff8000216bb4b8,ffff8000216bb510) at sys_write+0x83 sys/kern/sys_generic.c:301 syscall(ffff8000216bb580) at syscall+0x44e sys/arch/amd64/amd64/trap.c:585 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xea2dce8fe40, 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(ffffffff82547276) at panic+0x161 sys/kern/subr_prf.c:202 __assert(ffffffff825bae63,ffffffff825cabcb,568,ffffffff8255b781) at __assert+0x25 sys/kern/subr_prf.c:161 m_align(fffffd8073225c00,ffffffc1) at m_align+0x1a0 sys/kern/uipc_mbuf.c:1385 bpf_movein(ffff8000216bb418,ffff800000c5c800,ffff8000216bb178,ffff8000216bb078) at bpf_movein+0x25e sys/net/bpf.c:228 bpfwrite(41700,ffff8000216bb418,11) at bpfwrite+0x128 sys/net/bpf.c:644 spec_write(ffff8000216bb270) at spec_write+0xcb sys/kern/spec_vnops.c:309 VOP_WRITE(fffffd8063da5888,ffff8000216bb418,11,fffffd807f7d8b40) at VOP_WRITE+0xbf sys/kern/vfs_vops.c:245 vn_write(fffffd8067bcbd28,ffff8000216bb418,0) at vn_write+0x152 sys/kern/vfs_vnops.c:414 dofilewritev(ffff80002e7e7a50,3,ffff8000216bb418,0,ffff8000216bb510) at dofilewritev+0x19c sys/kern/sys_generic.c:381 sys_write(ffff80002e7e7a50,ffff8000216bb4b8,ffff8000216bb510) at sys_write+0x83 sys/kern/sys_generic.c:301 syscall(ffff8000216bb580) at syscall+0x44e sys/arch/amd64/amd64/trap.c:585 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xea2dce8fe40, count: -13