# Iteration 1 panic (MY PoC bug, NOT the kernel finding): first module version # ran two consumer lwkt threads on a single SPSC ring -> same slot popped twice # -> same chunk kfree()d twice -> INVARIANTS bitmap caught it exactly as designed. # Fixed by giving each consumer its own ring (NRING=2). Kept for honesty. slabstrand: run 3s size=2048 which=7 panic: memory chunk 0xfffff80118932000 is already free! cpuid = 0 Trace beginning at frame 0xfffff8011859fa00 chunk_mark_free() at chunk_mark_free+0xae 0xffffffff80655dbe chunk_mark_free() at chunk_mark_free+0xae 0xffffffff80655dbe _kmalloc() at _kmalloc+0x97e 0xffffffff8065773e producer_loop() at producer_loop+0x5c 0xffffffff826004bc Debugger("panic")