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,ffffffff81ecbc58) at pool_do_put+0x339 pool_put(0,ffffff0006000100) at pool_put+0x37 m_free(ffffff0006000100) at m_free+0x12c mq_purge(ffff800000aca600) at mq_purge+0x6d switchclose(ffff8000210c3528,ffff80002110e698,ffffffff818e10a7,ffff80002110e640) at switchclose+0x77 spec_close(ffffffff81dfb940) at spec_close+0x271 VOP_CLOSE(ffffff006e1e9900,ffff8000210c3528,ffffff007f7c7ba0,3) at VOP_CLOSE+0x5f vn_closefile(ffff8000210c3528,ffffff006e471170) at vn_closefile+0xfc fdrop(ffffff006e471170,ffff8000210c3528) at fdrop+0xa4 closef(ffff8000210c3528,ffffff006e994d48) at closef+0xd5 fdfree(ffff80002105f330) at fdfree+0x98 exit1(ffff80002110e960,ffff8000210c3528,ffff80002105f330) at exit1+0x22f end trace frame: 0xffff80002110e880, 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,ffffffff81ecbc58) at pool_do_put+0x339 pool_put(0,ffffff0006000100) at pool_put+0x37 m_free(ffffff0006000100) at m_free+0x12c mq_purge(ffff800000aca600) at mq_purge+0x6d switchclose(ffff8000210c3528,ffff80002110e698,ffffffff818e10a7,ffff80002110e640) at switchclose+0x77 spec_close(ffffffff81dfb940) at spec_close+0x271 VOP_CLOSE(ffffff006e1e9900,ffff8000210c3528,ffffff007f7c7ba0,3) at VOP_CLOSE+0x5f vn_closefile(ffff8000210c3528,ffffff006e471170) at vn_closefile+0xfc fdrop(ffffff006e471170,ffff8000210c3528) at fdrop+0xa4 closef(ffff8000210c3528,ffffff006e994d48) at closef+0xd5 fdfree(ffff80002105f330) at fdfree+0x98 exit1(ffff80002110e960,ffff8000210c3528,ffff80002105f330) at exit1+0x22f sys_exit(ffffffff81ab3003,ffff80002110e880,ffff80002110e960) at sys_exit+0x13 syscall(0) at syscall+0x3e4 Xsyscall(6,1,0,1,7f7fffff1fd0,0) at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff1fc0, count: -17 ddb> show registers rdi 0xffffffff81e10dd8 kprintf_mutex rsi 0x5 rbp 0xffff80002110e450 rbx 0xffff80002110e4f0 rdx 0x3fd rcx 0 rax 0 r8 0xffff80002110e420 r9 0x8080808080808080 r10 0 r11 0xffffffff8174f9a0 x86_bus_space_io_read_1 r12 0x3000000008 r13 0xffff80002110e460 r14 0x100 r15 0xffffffff81c13cbf apollo_udma100_tim+0x4253 rip 0xffffffff81679b8a db_enter+0xa cs 0x8 rflags 0x246 rsp 0xffff80002110e450 ss 0x10 db_enter+0xa: popq %rbp ddb> show proc PROC (syz-executor1529) pid=256821 stat=onproc flags process=1008 proc=2000 pri=50, usrpri=52, nice=20 forw=0xffffffffffffffff, list=0xffff8000210c24c0,0xffff8000210c2980 process=0xffff80002105f330 user=0xffff800021109000, vmspace=0xffffff007f12bc60 estcpu=2, cpticks=3, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 92269 24317 56229 0 2 0 syz-executor1529 92269 296183 56229 0 3 0x4000080 fsleep syz-executor1529 56229 184095 58894 0 3 0x80 nanosleep syz-executor1529 79067 184662 58894 0 3 0x80 nanosleep syz-executor1529 58894 303198 95543 0 3 0x82 nanosleep syz-executor1529 95543 281058 10636 0 3 0x10008a pause ksh 10636 168310 76093 0 3 0x92 select sshd 94196 121686 1 0 3 0x100083 ttyin getty 76093 324165 1 0 3 0x80 select sshd 79609 491412 86175 73 3 0x100090 kqread syslogd 86175 329814 1 0 3 0x100082 netio syslogd 17870 299425 1 77 3 0x100090 poll dhclient 6644 4573 1 0 3 0x80 poll dhclient 32923 101997 0 0 2 0x14200 zerothread 9610 506004 0 0 3 0x14200 aiodoned aiodoned 41544 500091 0 0 3 0x14200 syncer update 77298 147067 0 0 3 0x14200 cleaner cleaner 32985 9534 0 0 3 0x14200 reaper reaper 38828 104275 0 0 3 0x14200 pgdaemon pagedaemon 26122 450894 0 0 3 0x14200 bored crynlk 44138 482470 0 0 3 0x14200 bored crypto 33502 211846 0 0 3 0x40014200 acpi0 acpi0 45102 375338 0 0 3 0x14200 bored softnet 49751 428803 0 0 3 0x14200 bored systqmp 24903 429017 0 0 3 0x14200 bored systq 758 266970 0 0 3 0x40014200 bored softclock 95851 33566 0 0 3 0x40014200 idle0 1 478748 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper