panic: pr_find_pagehead: mbufpl: page header missing Stopped at db_enter+0xa: popq %rbp TID PID UID PRFLAGS PFLAGS CPU COMMAND db_enter() at db_enter+0xa panic() at panic+0x147 pool_do_put(ffffff0006000100,ffffffff81e958e8) at pool_do_put+0x339 pool_put(0,ffffff0006000100) at pool_put+0x37 m_free(ffffff0006000100) at m_free+0x12c mq_purge(ffff8000036cf880) at mq_purge+0x6d switchclose(ffff800021142e50,ffff800021176088,ffffffff81397c37,ffff800021176030) at switchclose+0x77 spec_close(ffffffff81e25a68) at spec_close+0x271 VOP_CLOSE(ffffff005e804928,ffff800021142e50,ffffff007f7c7ba0,3) at VOP_CLOSE+0x5f vn_closefile(ffff800021142e50,ffffff0006594b50) at vn_closefile+0xfc fdrop(ffffff0006594b50,ffff800021142e50) at fdrop+0xa4 closef(ffff800021142e50,ffffff006e9d4ba0) at closef+0xd5 fdfree(ffff8000210602f8) at fdfree+0x98 exit1(ffff800021176350,ffff800021142e50,ffff8000210602f8) at exit1+0x22f end trace frame: 0xffff800021176270, count: 0 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> show panic pr_find_pagehead: mbufpl: page header missing ddb> trace db_enter() at db_enter+0xa panic() at panic+0x147 pool_do_put(ffffff0006000100,ffffffff81e958e8) at pool_do_put+0x339 pool_put(0,ffffff0006000100) at pool_put+0x37 m_free(ffffff0006000100) at m_free+0x12c mq_purge(ffff8000036cf880) at mq_purge+0x6d switchclose(ffff800021142e50,ffff800021176088,ffffffff81397c37,ffff800021176030) at switchclose+0x77 spec_close(ffffffff81e25a68) at spec_close+0x271 VOP_CLOSE(ffffff005e804928,ffff800021142e50,ffffff007f7c7ba0,3) at VOP_CLOSE+0x5f vn_closefile(ffff800021142e50,ffffff0006594b50) at vn_closefile+0xfc fdrop(ffffff0006594b50,ffff800021142e50) at fdrop+0xa4 closef(ffff800021142e50,ffffff006e9d4ba0) at closef+0xd5 fdfree(ffff8000210602f8) at fdfree+0x98 exit1(ffff800021176350,ffff800021142e50,ffff8000210602f8) at exit1+0x22f sys_exit(ffffffff811d29d3,ffff800021176270,ffff800021176350) at sys_exit+0x13 syscall(0) at syscall+0x3e4 Xsyscall(6,1,0,1,0,7f7ffffc4e80) at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc4e30, count: -17 ddb> show registers rdi 0xffffffff81e02af0 kprintf_mutex rsi 0x5 rbp 0xffff800021175e40 rbx 0xffff800021175ee0 rdx 0x3fd rcx 0 rax 0 r8 0xffff800021175e10 r9 0x8080808080808080 r10 0 r11 0xffffffff810d5f70 x86_bus_space_io_read_1 r12 0x3000000008 r13 0xffff800021175e50 r14 0x100 r15 0xffffffff81c11858 apollo_udma100_tim+0x216e rip 0xffffffff8175717a db_enter+0xa cs 0x8 rflags 0x246 rsp 0xffff800021175e40 ss 0x10 db_enter+0xa: popq %rbp ddb> show proc PROC (syz-executor1) pid=519496 stat=onproc flags process=1008 proc=2000 pri=63, usrpri=63, nice=20 forw=0xffffffffffffffff, list=0xffff8000211424f0,0xffffffff81ea46e8 process=0xffff8000210602f8 user=0xffff800021171000, vmspace=0xffffff007f12ca50 estcpu=13, cpticks=1, pctcpu=0.0 user=0, sys=1, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 67009 477106 1 0 3 0x100083 ttyin getty 31519 116302 0 0 3 0x14200 bored sosplice 93715 425356 7041 0 3 0x82 nanosleep syz-executor1 60084 215403 7041 0 3 0x2 biowait syz-executor0 7041 368675 58548 0 3 0x82 thrsleep syz-fuzzer 7041 61390 58548 0 3 0x4000082 nanosleep syz-fuzzer 7041 157430 58548 0 3 0x4000082 thrsleep syz-fuzzer 7041 102694 58548 0 3 0x4000082 thrsleep syz-fuzzer 7041 46915 58548 0 3 0x4000082 kqread syz-fuzzer 7041 264932 58548 0 3 0x4000082 thrsleep syz-fuzzer 7041 107548 58548 0 3 0x4000082 thrsleep syz-fuzzer 58548 236512 40291 0 3 0x10008a pause ksh 40291 390480 67960 0 3 0x92 select sshd 67960 45833 1 0 3 0x80 select sshd 4771 289645 15460 73 3 0x100090 kqread syslogd 15460 320717 1 0 3 0x100082 netio syslogd 25364 293618 1 77 3 0x100090 poll dhclient 24590 44326 1 0 3 0x80 poll dhclient 98139 113499 0 0 2 0x14200 zerothread 54158 214046 0 0 3 0x14200 aiodoned aiodoned 59075 430207 0 0 3 0x14200 syncer update 76393 117637 0 0 3 0x14200 cleaner cleaner 51278 467806 0 0 3 0x14200 reaper reaper 91533 409213 0 0 3 0x14200 pgdaemon pagedaemon 79656 9292 0 0 3 0x14200 bored crynlk 92129 378216 0 0 3 0x14200 bored crypto 76751 505455 0 0 3 0x40014200 acpi0 acpi0 87799 447142 0 0 3 0x14200 bored softnet 45018 382334 0 0 3 0x14200 bored systqmp 52187 346980 0 0 3 0x14200 bored systq 5742 511016 0 0 3 0x40014200 bored softclock 1293 113164 0 0 3 0x40014200 idle0 1 122073 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper