On 9/26/20 4:58 AM, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 98477740 Merge branch 'rcu/urgent' of git://git.kernel.org.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=153e929b900000 > kernel config: https://syzkaller.appspot.com/x/.config?x=af502ec9a451c9fc > dashboard link: https://syzkaller.appspot.com/bug?extid=9af99580130003da82b1 > compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14138009900000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17d0f809900000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+9af99580130003da82b1@xxxxxxxxxxxxxxxxxxxxxxxxx > > ================================================================== > BUG: KASAN: use-after-free in __lock_acquire+0x92/0x2ae0 kernel/locking/lockdep.c:4311 > Read of size 8 at addr ffff88821ae5f818 by task io_wqe_worker-0/11054 > > CPU: 1 PID: 11054 Comm: io_wqe_worker-0 Not tainted 5.9.0-rc6-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x1d6/0x29e lib/dump_stack.c:118 > print_address_description+0x66/0x620 mm/kasan/report.c:383 > __kasan_report mm/kasan/report.c:513 [inline] > kasan_report+0x132/0x1d0 mm/kasan/report.c:530 > __lock_acquire+0x92/0x2ae0 kernel/locking/lockdep.c:4311 > lock_acquire+0x148/0x720 kernel/locking/lockdep.c:5029 > __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline] > _raw_spin_lock_irq+0xa6/0xc0 kernel/locking/spinlock.c:167 > spin_lock_irq include/linux/spinlock.h:379 [inline] > io_wqe_worker+0x756/0x810 fs/io-wq.c:589 > kthread+0x37e/0x3a0 drivers/block/aoe/aoecmd.c:1234 > ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 > > Allocated by task 11048: > kasan_save_stack mm/kasan/common.c:48 [inline] > kasan_set_track mm/kasan/common.c:56 [inline] > __kasan_kmalloc+0x100/0x130 mm/kasan/common.c:461 > kmem_cache_alloc_node_trace+0x1f7/0x2a0 mm/slab.c:3594 > kmalloc_node include/linux/slab.h:572 [inline] > kzalloc_node include/linux/slab.h:677 [inline] > io_wq_create+0x295/0x880 fs/io-wq.c:1064 > io_init_wq_offload fs/io_uring.c:7432 [inline] > io_sq_offload_start fs/io_uring.c:7504 [inline] > io_uring_create fs/io_uring.c:8625 [inline] > io_uring_setup fs/io_uring.c:8694 [inline] > __do_sys_io_uring_setup fs/io_uring.c:8700 [inline] > __se_sys_io_uring_setup+0x18ed/0x2a00 fs/io_uring.c:8697 > do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > Freed by task 128: > kasan_save_stack mm/kasan/common.c:48 [inline] > kasan_set_track+0x3d/0x70 mm/kasan/common.c:56 > kasan_set_free_info+0x17/0x30 mm/kasan/generic.c:355 > __kasan_slab_free+0xdd/0x110 mm/kasan/common.c:422 > __cache_free mm/slab.c:3418 [inline] > kfree+0x113/0x200 mm/slab.c:3756 > __io_wq_destroy fs/io-wq.c:1138 [inline] > io_wq_destroy+0x470/0x510 fs/io-wq.c:1146 > io_finish_async fs/io_uring.c:6836 [inline] > io_ring_ctx_free fs/io_uring.c:7870 [inline] > io_ring_exit_work+0x195/0x520 fs/io_uring.c:7954 > process_one_work+0x789/0xfc0 kernel/workqueue.c:2269 > worker_thread+0xaa4/0x1460 kernel/workqueue.c:2415 > kthread+0x37e/0x3a0 drivers/block/aoe/aoecmd.c:1234 > ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 > > The buggy address belongs to the object at ffff88821ae5f800 > which belongs to the cache kmalloc-1k of size 1024 > The buggy address is located 24 bytes inside of > 1024-byte region [ffff88821ae5f800, ffff88821ae5fc00) > The buggy address belongs to the page: > page:000000008e41b1c2 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x21ae5f > flags: 0x57ffe0000000200(slab) > raw: 057ffe0000000200 ffffea00086a10c8 ffffea00085d1848 ffff8880aa440700 > raw: 0000000000000000 ffff88821ae5f000 0000000100000002 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff88821ae5f700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff88821ae5f780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >> ffff88821ae5f800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff88821ae5f880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff88821ae5f900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ================================================================== Hillf, you've been looking at this one, care to spend a bit of time on it and pull it to completion? -- Jens Axboe
