panic: pool_do_put: mbufpl: double pool_put: 0xffffff00736c0800 Stopped at db_enter+0xa: popq %rbp TID PID UID PRFLAGS PFLAGS CPU COMMAND *356261 65950 0 0 0x4000000 0 syz-executor0 db_enter() at db_enter+0xa panic() at panic+0x147 pool_do_put(ffffff00736c0800,ffffffff81ecbc58) at pool_do_put+0x2e2 pool_put(4652bed4755a7bca,ffffff00736c0800) at pool_put+0x37 m_free(ffffff00736c0800) at m_free+0x12c m_freem(16) at m_freem+0x2d soreceive(0,ffffff006f2e6900,ffff800021172c30,14b,ffff800021172cc0,ffff800021172bd0) at soreceive+0x1131 recvit(ffff800021172cf0,ffff800021172df8,ffff800021172de0,ffff8000ffffce18,0) at recvit+0x28c sys_recvmsg(ffff800021172e80,ffff8000ffffce18,ffff8000210a5010) at sys_recvmsg+0x120 syscall(0) at syscall+0x3e4 Xsyscall(6,0,ffffffffffffffbf,0,3,1482965f010) at Xsyscall+0x128 end of kernel end trace frame: 0x14a497c0ef0, count: 4 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: mbufpl: double pool_put: 0xffffff00736c0800 ddb> trace db_enter() at db_enter+0xa panic() at panic+0x147 pool_do_put(ffffff00736c0800,ffffffff81ecbc58) at pool_do_put+0x2e2 pool_put(4652bed4755a7bca,ffffff00736c0800) at pool_put+0x37 m_free(ffffff00736c0800) at m_free+0x12c m_freem(16) at m_freem+0x2d soreceive(0,ffffff006f2e6900,ffff800021172c30,14b,ffff800021172cc0,ffff800021172bd0) at soreceive+0x1131 recvit(ffff800021172cf0,ffff800021172df8,ffff800021172de0,ffff8000ffffce18,0) at recvit+0x28c sys_recvmsg(ffff800021172e80,ffff8000ffffce18,ffff8000210a5010) at sys_recvmsg+0x120 syscall(0) at syscall+0x3e4 Xsyscall(6,0,ffffffffffffffbf,0,3,1482965f010) at Xsyscall+0x128 end of kernel end trace frame: 0x14a497c0ef0, count: -11 ddb> show registers rdi 0xffffffff81e10dd8 kprintf_mutex rsi 0xffffffff81679b89 db_enter+0x9 rbp 0xffff800021172950 rbx 0xffff8000211729f0 rdx 0xffff800002acc000 rcx 0x1d05 __ALIGN_SIZE+0xd05 rax 0xffff800002acc000 r8 0xffff800021172920 r9 0x8080808080808080 r10 0x4652bed4755a7bca r11 0xffffffff8174f9a0 x86_bus_space_io_read_1 r12 0x3000000008 r13 0xffff800021172960 r14 0x100 r15 0xffffffff81c3c06c cy_pio_rec+0x4090 rip 0xffffffff81679b8a db_enter+0xa cs 0x8 rflags 0x206 rsp 0xffff800021172950 ss 0x10 db_enter+0xa: popq %rbp ddb> show proc PROC (syz-executor0) pid=356261 stat=onproc flags process=0 proc=4000000 pri=75, usrpri=75, nice=20 forw=0xffffffffffffffff, list=0xffff8000ffffcbc0,0xffffffff81eafaa0 process=0xffff8000210a5010 user=0xffff80002116d000, vmspace=0xffffff007f12b420 estcpu=36, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 65950 170859 91301 0 2 0 syz-executor0 *65950 356261 91301 0 7 0x4000000 syz-executor0 46557 125189 63691 0 3 0x80 nanosleep syz-executor1 46557 168149 63691 0 3 0x4000080 ttyin syz-executor1 32740 154487 0 0 3 0x14200 bored sosplice 91301 227740 5366 0 3 0x82 nanosleep syz-executor0 63691 375353 5366 0 3 0x82 nanosleep syz-executor1 5366 188135 70383 0 3 0x82 thrsleep syz-fuzzer 5366 92670 70383 0 3 0x4000082 nanosleep syz-fuzzer 5366 74147 70383 0 3 0x4000082 thrsleep syz-fuzzer 5366 21266 70383 0 3 0x4000082 kqread syz-fuzzer 5366 1054 70383 0 3 0x4000082 thrsleep syz-fuzzer 5366 323873 70383 0 3 0x4000082 thrsleep syz-fuzzer 5366 206216 70383 0 3 0x4000082 thrsleep syz-fuzzer 70383 194300 79968 0 3 0x10008a pause ksh 79968 122716 10872 0 3 0x92 select sshd 82671 7868 1 0 3 0x100083 ttyin getty 10872 239437 1 0 3 0x80 select sshd 60541 118351 30648 73 3 0x100090 kqread syslogd 30648 283851 1 0 3 0x100082 netio syslogd 55122 271063 1 77 3 0x100090 poll dhclient 62839 245936 1 0 3 0x80 poll dhclient 35341 280820 0 0 2 0x14200 zerothread 91003 383329 0 0 3 0x14200 aiodoned aiodoned 25106 12791 0 0 3 0x14200 syncer update 1804 57432 0 0 3 0x14200 cleaner cleaner 37553 172569 0 0 3 0x14200 reaper reaper 10540 182063 0 0 3 0x14200 pgdaemon pagedaemon 85035 511761 0 0 3 0x14200 bored crynlk 26763 161618 0 0 3 0x14200 bored crypto 66625 335791 0 0 3 0x40014200 acpi0 acpi0 58857 77479 0 0 3 0x14200 bored softnet 7220 207815 0 0 3 0x14200 bored systqmp 29207 359656 0 0 3 0x14200 bored systq 20363 178078 0 0 3 0x40014200 bored softclock 18662 262039 0 0 3 0x40014200 idle0 1 213407 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper