panic: pool_do_put: mcl2k: double pool_put: 0xffffff006d9ad800 Stopped at db_enter+0xa: popq %rbp TID PID UID PRFLAGS PFLAGS CPU COMMAND *176923 4196 0 0 0x4000000 0 syz-executor1 db_enter() at db_enter+0xa panic() at panic+0x147 pool_do_put(ffffff006d9ad800,ffffffff81ea61e0) at pool_do_put+0x2e2 pool_put(0,ffffff0072536700) at pool_put+0x37 m_extfree(97cb50c8e74dc718) at m_extfree+0xb1 m_free(ffffff0072536700) at m_free+0xee m_freem(16) at m_freem+0x2d soreceive(0,ffffff006e70bd88,ffff800021195e40,1ff,ffff800021195ed0,ffff800021195de0) at soreceive+0x1131 recvit(ffff800021195f00,ffff800021196008,ffff800021195ff0,ffff8000ffffa728,0) at recvit+0x28c sys_recvmsg(ffff800021196090,ffff8000ffffa728,ffff80002105f658) at sys_recvmsg+0x120 syscall(0) at syscall+0x3e4 Xsyscall(6,0,ffffffffffffffbf,0,3,4a9c354d010) at Xsyscall+0x128 end of kernel end trace frame: 0x4ac88b1b420, count: 3 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 pool_do_put: mcl2k: double pool_put: 0xffffff006d9ad800 ddb> trace db_enter() at db_enter+0xa panic() at panic+0x147 pool_do_put(ffffff006d9ad800,ffffffff81ea61e0) at pool_do_put+0x2e2 pool_put(0,ffffff0072536700) at pool_put+0x37 m_extfree(97cb50c8e74dc718) at m_extfree+0xb1 m_free(ffffff0072536700) at m_free+0xee m_freem(16) at m_freem+0x2d soreceive(0,ffffff006e70bd88,ffff800021195e40,1ff,ffff800021195ed0,ffff800021195de0) at soreceive+0x1131 recvit(ffff800021195f00,ffff800021196008,ffff800021195ff0,ffff8000ffffa728,0) at recvit+0x28c sys_recvmsg(ffff800021196090,ffff8000ffffa728,ffff80002105f658) at sys_recvmsg+0x120 syscall(0) at syscall+0x3e4 Xsyscall(6,0,ffffffffffffffbf,0,3,4a9c354d010) at Xsyscall+0x128 end of kernel end trace frame: 0x4ac88b1b420, count: -12 ddb> show registers rdi 0xffffffff81e01078 kprintf_mutex rsi 0xffffffff818dd6d9 db_enter+0x9 rbp 0xffff800021195b40 rbx 0xffff800021195be0 rdx 0xffff800000acb000 rcx 0x1dbe __ALIGN_SIZE+0xdbe rax 0xffff800000acb000 r8 0xffff800021195b10 r9 0x8080808080808080 r10 0x97cb50c8e74dc718 r11 0xffffffff81a5c910 x86_bus_space_io_read_1 r12 0x3000000008 r13 0xffff800021195b50 r14 0x100 r15 0xffffffff81c3edad cy_pio_rec+0x9efc rip 0xffffffff818dd6da db_enter+0xa cs 0x8 rflags 0x206 rsp 0xffff800021195b40 ss 0x10 db_enter+0xa: popq %rbp ddb> show proc PROC (syz-executor1) pid=176923 stat=onproc flags process=0 proc=4000000 pri=86, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff8000ffffbc40,0xffff8000ffffae40 process=0xffff80002105f658 user=0xffff800021191000, vmspace=0xffffff007f12b840 estcpu=36, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 4196 207317 41366 0 2 0 syz-executor1 * 4196 176923 41366 0 7 0x4000000 syz-executor1 48021 145332 50181 0 2 0 syz-executor0 48021 223799 50181 0 3 0x4000080 ttyout syz-executor0 48021 514810 50181 0 3 0x4000000 fdlock syz-executor0 11493 277744 1 0 3 0x100083 ttyin getty 40537 499672 0 0 3 0x14200 bored sosplice 50181 18375 49076 0 3 0x82 nanosleep syz-executor0 41366 94100 49076 0 3 0x82 nanosleep syz-executor1 49076 354550 29605 0 3 0x82 thrsleep syz-fuzzer 49076 266601 29605 0 3 0x4000082 thrsleep syz-fuzzer 49076 205521 29605 0 3 0x4000082 thrsleep syz-fuzzer 49076 383157 29605 0 3 0x4000082 thrsleep syz-fuzzer 49076 322146 29605 0 3 0x4000082 kqread syz-fuzzer 49076 94805 29605 0 3 0x4000082 thrsleep syz-fuzzer 49076 100998 29605 0 3 0x4000082 thrsleep syz-fuzzer 29605 183150 35211 0 3 0x10008a pause ksh 35211 280648 67940 0 3 0x92 select sshd 67940 483540 1 0 3 0x80 select sshd 96549 449712 14272 73 3 0x100090 kqread syslogd 14272 485884 1 0 3 0x100082 netio syslogd 75100 52458 1 77 3 0x100090 poll dhclient 45870 277851 1 0 3 0x80 poll dhclient 76443 275439 0 0 2 0x14200 zerothread 28199 188063 0 0 3 0x14200 aiodoned aiodoned 17810 67402 0 0 3 0x14200 syncer update 60959 411053 0 0 3 0x14200 cleaner cleaner 92098 195884 0 0 3 0x14200 reaper reaper 45089 206708 0 0 3 0x14200 pgdaemon pagedaemon 67076 218641 0 0 3 0x14200 bored crynlk 20851 179119 0 0 3 0x14200 bored crypto 35908 336287 0 0 3 0x40014200 acpi0 acpi0 41320 22792 0 0 3 0x14200 bored softnet 95104 514570 0 0 3 0x14200 bored systqmp 2087 82205 0 0 3 0x14200 bored systq 35567 217262 0 0 3 0x40014200 bored softclock 52187 319518 0 0 3 0x40014200 idle0 1 480268 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper