login: panic: pool_do_get: semupl free list modified: page 0xffffff0064c6c000; item addr 0xffffff0064c6cef0; offset 0x10=0xdeadbef0 Stopped at db_enter+0xa: popq %rbp TID PID UID PRFLAGS PFLAGS CPU COMMAND *406835 93049 0 0 0x4000000 0 syz-executor0 db_enter() at db_enter+0xa panic() at panic+0x147 pool_do_get(2,ffffffff81ed1150,0) at pool_do_get+0x3e9 pool_get(ffff800021160b78,ffff8000ffffd2c8) at pool_get+0x77 semundo_adjust(ffffffffffffffff,ffff800021160b78,ffff8000ffffd2c8,ffffff006e4e4ee0,ffff800021160b7e) at semundo_adjust+0xd5 sys_semop(ffff800021160cc0,ffff8000ffffd2c8,ffff8000210a5988) at sys_semop+0x5a8 syscall(0) at syscall+0x3e4 Xsyscall(6,0,ffffffffffffffd0,0,3,1353b718010) at Xsyscall+0x128 end of kernel end trace frame: 0x137592a66a0, count: 7 https://www.openbsd.org/ddb.html describes the minimum info required in bug reports. Insufficient info makes it difficult to find and fix bugs.