panic: pool_cache_item_magic_check: mbufpl cpu free list modified: item addr 0xfffffd8066255200+16 0x0!=0x9d08f969c9bdb95d Stopped at db_enter+0x1c: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND * 11477 5205 0 0x1a000002 0x4000000 1 syz-fuzzer 122505 94007 0 0x14000 0x200 0 softnet0 db_enter() at db_enter+0x1c sys/arch/amd64/amd64/db_interface.c:437 panic(ffffffff8284c656) at panic+0x17b sys/kern/subr_prf.c:198 pool_cache_get(ffffffff82e2e178) at pool_cache_get+0x302 pool_get(ffffffff82e2e178,1) at pool_get+0x96 sys/kern/subr_pool.c:573 m_gethdr(1,1) at m_gethdr+0x67 sys/kern/uipc_mbuf.c:276 m_getuio(ffff80002a209fa0,0,43af,ffff80002a20a0f8) at m_getuio+0xa4 sys/kern/uipc_socket.c:706 sosend(ffff800010fd4fa0,0,ffff80002a20a0f8,0,0,80) at sosend+0x524 sys/kern/uipc_socket.c:660 dofilewritev(ffff80002a1aece8,6,ffff80002a20a0f8,0,ffff80002a20a1b0) at dofilewritev+0x1a9 sys/kern/sys_generic.c:375 sys_write(ffff80002a1aece8,ffff80002a20a260,ffff80002a20a1b0) at sys_write+0x87 sys/kern/sys_generic.c:295 syscall(ffff80002a20a260) at syscall+0x8cf mi_syscall sys/sys/syscall_mi.h:180 [inline] syscall(ffff80002a20a260) at syscall+0x8cf sys/arch/amd64/amd64/trap.c:577 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x2bfdb9590, 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.