panic: pool_cache_item_magic_check: mbufpl cpu free list modified: item addr 0xfffffd806beee200+16 0x0!=0x4bc9bf8fc1bdb680 Stopped at db_enter+0x25: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 480501 39595 0 0x8000000 0 1 syz-executor *343863 39595 0 0x8000000 0x4000000 0 syz-executor db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:437 panic(ffffffff82fd648a) at panic+0x1e5 sys/kern/subr_prf.c:198 pool_cache_get(ffffffff8353b718) at pool_cache_get+0x3e4 pool_get(ffffffff8353b718,2) at pool_get+0xba m_get(2,3) at m_get+0x82 sys/kern/uipc_mbuf.c:243 sbappendaddr(ffff8000012ead58,ffff8000012eae18,ffffffff8336ae10,fffffd8079a42b00,0) at sbappendaddr+0x47e uipc_dgram_send(ffff8000012ea2f8,fffffd8079a42b00,0,0) at uipc_dgram_send+0x218 sys/kern/uipc_usrreq.c:622 sosend(ffff8000012ea2f8,0,ffff80002a0ae858,0,0,0) at sosend+0xa40 sendit(ffff80002a03b1d0,3,ffff80002a0ae9e0,0,ffff80002a0ae9d0) at sendit+0x721 sys/kern/uipc_syscalls.c:786 sys_sendmmsg(ffff80002a03b1d0,ffff80002a0aeb80,ffff80002a0aead0) at sys_sendmmsg+0x3f3 sys/kern/uipc_syscalls.c:677 syscall(ffff80002a0aeb80) at syscall+0xbb6 mi_syscall sys/sys/syscall_mi.h:179 [inline] syscall(ffff80002a0aeb80) at syscall+0xbb6 sys/arch/amd64/amd64/trap.c:577 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xa4354d41d90, 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.