On Thu, Jan 14, 2016 at 10:07:31PM -0500, Dave Jones wrote: > I just hit a bunch of instances of this spew.. > This is on Linus' tree from a few hours ago > > ================================================================== > BUG: KASAN: use-after-free in perf_trace_btrfs__work+0x1b1/0x2a0 [btrfs] at > addr ffff8800b7ea2e60 > Read of size 8 by task trinity-c14/6745 > ============================================================================= > BUG kmalloc-256 (Not tainted): kasan: bad access detected > ----------------------------------------------------------------------------- > > Disabling lock debugging due to kernel taint > INFO: Allocated in btrfs_wq_submit_bio+0xd1/0x300 [btrfs] age=63 cpu=1 > pid=6745 > ___slab_alloc.constprop.70+0x4de/0x580 > __slab_alloc.isra.67.constprop.69+0x48/0x80 > kmem_cache_alloc_trace+0x24c/0x2e0 > btrfs_wq_submit_bio+0xd1/0x300 [btrfs] > btrfs_submit_bio_hook+0x118/0x260 [btrfs] > neigh_sysctl_register+0x201/0x360 > devinet_sysctl_register+0x73/0xe0 > inetdev_init+0x119/0x1f0 > inetdev_event+0x5b3/0x7e0 > notifier_call_chain+0x4e/0xd0 > raw_notifier_call_chain+0x16/0x20 > call_netdevice_notifiers_info+0x3d/0x70 > register_netdevice+0x62d/0x730 > register_netdev+0x1a/0x30 > loopback_net_init+0x5d/0xd0 > ops_init+0x5b/0x1e0 > INFO: Freed in run_one_async_free+0x12/0x20 [btrfs] age=177 cpu=1 pid=8018 > __slab_free+0x19e/0x2d0 > kfree+0x24e/0x270 > run_one_async_free+0x12/0x20 [btrfs] > btrfs_scrubparity_helper+0x38d/0x740 [btrfs] > btrfs_worker_helper+0xe/0x10 [btrfs] > process_one_work+0x417/0xa40 > worker_thread+0x8b/0x730 > kthread+0x199/0x1c0 > ret_from_fork+0x3f/0x70 > INFO: Slab 0xffffea0002dfa800 objects=28 used=28 fp=0x (null) > flags=0x4000000000004080 > INFO: Object 0xffff8800b7ea2da0 @offset=11680 fp=0xffff8800b7ea2480
static inline void __btrfs_queue_work(struct __btrfs_workqueue *wq, struct btrfs_work *work) { unsigned long flags; work->wq = wq; thresh_queue_hook(wq); if (work->ordered_func) { spin_lock_irqsave(&wq->list_lock, flags); list_add_tail(&work->ordered_list, &wq->ordered_list); spin_unlock_irqrestore(&wq->list_lock, flags); } queue_work(wq->normal_wq, &work->normal_work); trace_btrfs_work_queued(work); } Qu, 'work' can be freed before queue_work returns. I don't see any reason here to have it after the queue_work() call, do you? -chris