In the Linux kernel, the following vulnerability has been resolved: nvmet: fix race in nvmetbiodone() leading to NULL pointer dereference There is a race condition in nvmetbiodone() that can cause a NULL pointer dereference in blkcgroupbiostart(): 1. nvmetbiodone() is called when a bio completes 2. nvmetreqcomplete() is called, which invokes req->ops->queueresponse(req) 3. The queueresponse callback can re-queue and re-submit the same request 4. The re-submission reuses the same inlinebio from nvmetreq 5. Meanwhile, nvmetreqbioput() (called after nvmetreqcomplete) invokes biouninit() for inlinebio, which sets bio->biblkg to NULL 6. The re-submitted bio enters submitbionoacctnocheck() 7. blkcgroupbiostart() dereferences bio->biblkg, causing a crash: BUG: kernel NULL pointer dereference, address: 0000000000000028 #PF: supervisor read access in kernel mode RIP: 0010:blkcgroupbiostart+0x10/0xd0 Call Trace: submitbionoacctnocheck+0x44/0x250 nvmetbdevexecuterw+0x254/0x370 [nvmet] processonework+0x193/0x3c0 workerthread+0x281/0x3a0 Fix this by reordering nvmetbiodone() to call nvmetreqbioput() BEFORE nvmetreq_complete(). This ensures the bio is cleaned up before the request can be re-submitted, preventing the race condition.