On Wed, Oct 30, 2019 at 1:52 PM syzbot <syzbot+6d8505fcdf25f00ac276@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > Hello, > > syzbot found the following crash on: > > HEAD commit: ff6409a6 usb-fuzzer: main usb gadget fuzzer driver > git tree: https://github.com/google/kasan.git usb-fuzzer > console output: https://syzkaller.appspot.com/x/log.txt?x=15e1ba24e00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=3230c37d442895b7 > dashboard link: https://syzkaller.appspot.com/bug?extid=6d8505fcdf25f00ac276 > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=169b8904e00000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=166f3104e00000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+6d8505fcdf25f00ac276@xxxxxxxxxxxxxxxxxxxxxxxxx > > usb 3-1: string descriptor 0 read error: -71 > usb 3-1: USB disconnect, device number 2 > ================================================================== > BUG: KASAN: use-after-free in atomic_read > include/asm-generic/atomic-instrumented.h:26 [inline] > BUG: KASAN: use-after-free in refcount_inc_not_zero_checked+0x72/0x1e0 > lib/refcount.c:123 > Read of size 4 at addr ffff8881cf679820 by task kworker/1:1/1730 > > CPU: 1 PID: 1730 Comm: kworker/1:1 Not tainted 5.4.0-rc5+ #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Workqueue: usb_hub_wq hub_event > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0xca/0x13e lib/dump_stack.c:113 > print_address_description.constprop.0+0x36/0x50 mm/kasan/report.c:374 > __kasan_report.cold+0x1a/0x33 mm/kasan/report.c:506 > kasan_report+0xe/0x20 mm/kasan/common.c:634 > check_memory_region_inline mm/kasan/generic.c:185 [inline] > check_memory_region+0x128/0x190 mm/kasan/generic.c:192 > atomic_read include/asm-generic/atomic-instrumented.h:26 [inline] > refcount_inc_not_zero_checked+0x72/0x1e0 lib/refcount.c:123 > refcount_inc_checked+0x12/0x60 lib/refcount.c:156 > get_task_struct include/linux/sched/task.h:110 [inline] > kthread_stop+0x6c/0x610 kernel/kthread.c:554 > hwrng_unregister+0x190/0x210 drivers/char/hw_random/core.c:538 > chaoskey_disconnect+0x1b2/0x200 drivers/usb/misc/chaoskey.c:232 > usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423 > __device_release_driver drivers/base/dd.c:1134 [inline] > device_release_driver_internal+0x42f/0x500 drivers/base/dd.c:1165 > bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:532 > device_del+0x420/0xb20 drivers/base/core.c:2376 > usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237 > usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2200 > hub_port_connect drivers/usb/core/hub.c:5035 [inline] > hub_port_connect_change drivers/usb/core/hub.c:5324 [inline] > port_event drivers/usb/core/hub.c:5470 [inline] > hub_event+0x16f2/0x3800 drivers/usb/core/hub.c:5552 > process_one_work+0x92b/0x1530 kernel/workqueue.c:2269 > process_scheduled_works kernel/workqueue.c:2331 [inline] > worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417 > kthread+0x318/0x420 kernel/kthread.c:255 > ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 > > Allocated by task 2: > save_stack+0x1b/0x80 mm/kasan/common.c:69 > set_track mm/kasan/common.c:77 [inline] > __kasan_kmalloc mm/kasan/common.c:510 [inline] > __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:483 > slab_post_alloc_hook mm/slab.h:584 [inline] > slab_alloc_node mm/slub.c:2779 [inline] > kmem_cache_alloc_node+0xdc/0x310 mm/slub.c:2815 > alloc_task_struct_node kernel/fork.c:169 [inline] > dup_task_struct kernel/fork.c:865 [inline] > copy_process+0x4201/0x6470 kernel/fork.c:1851 > _do_fork+0x129/0xec0 kernel/fork.c:2366 > kernel_thread+0xaa/0xe0 kernel/fork.c:2453 > create_kthread kernel/kthread.c:278 [inline] > kthreadd+0x4a2/0x680 kernel/kthread.c:596 > ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 > > Freed by task 16: > save_stack+0x1b/0x80 mm/kasan/common.c:69 > set_track mm/kasan/common.c:77 [inline] > kasan_set_free_info mm/kasan/common.c:332 [inline] > __kasan_slab_free+0x130/0x180 mm/kasan/common.c:471 > slab_free_hook mm/slub.c:1424 [inline] > slab_free_freelist_hook mm/slub.c:1475 [inline] > slab_free mm/slub.c:3025 [inline] > kmem_cache_free+0xb9/0x380 mm/slub.c:3041 > __put_task_struct+0x1e2/0x4c0 kernel/fork.c:748 > put_task_struct include/linux/sched/task.h:119 [inline] > delayed_put_task_struct+0x1b4/0x2c0 kernel/exit.c:182 > __rcu_reclaim kernel/rcu/rcu.h:222 [inline] > rcu_do_batch kernel/rcu/tree.c:2157 [inline] > rcu_core+0x630/0x1ca0 kernel/rcu/tree.c:2377 > __do_softirq+0x221/0x912 kernel/softirq.c:292 > > The buggy address belongs to the object at ffff8881cf679800 > which belongs to the cache task_struct of size 5888 > The buggy address is located 32 bytes inside of > 5888-byte region [ffff8881cf679800, ffff8881cf67af00) > The buggy address belongs to the page: > page:ffffea00073d9e00 refcount:1 mapcount:0 mapping:ffff8881da116000 > index:0x0 compound_mapcount: 0 > flags: 0x200000000010200(slab|head) > raw: 0200000000010200 dead000000000100 dead000000000122 ffff8881da116000 > raw: 0000000000000000 0000000080050005 00000001ffffffff 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8881cf679700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff8881cf679780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > > ffff8881cf679800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff8881cf679880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8881cf679900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ================================================================== > > > --- > This bug is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > syzbot can test patches for this bug, for details see: > https://goo.gl/tpsmEJ#testing-patches #syz fix: USB: chaoskey: fix use-after-free on release
