==================================================================
BUG: KASAN: use-after-free in __lock_acquire+0x3556/0x4a30 kernel/locking/lockdep.c:3215
Read of size 8 at addr ffff888096f386d0 by task kworker/u4:1/31257

CPU: 1 PID: 31257 Comm: kworker/u4:1 Not tainted 5.0.0-rc3+ #40
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: ib_addr process_one_req
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1db/0x2d0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
 __lock_acquire+0x3556/0x4a30 kernel/locking/lockdep.c:3215
 lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3841
 __mutex_lock_common kernel/locking/mutex.c:925 [inline]
 __mutex_lock+0x12f/0x1670 kernel/locking/mutex.c:1072
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087
 addr_handler+0xf9/0x440 drivers/infiniband/core/cma.c:2970
 process_one_req+0x190/0x940 drivers/infiniband/core/addr.c:643
 process_one_work+0xd0c/0x1ce0 kernel/workqueue.c:2153
 worker_thread+0x143/0x14a0 kernel/workqueue.c:2296
 kthread+0x357/0x430 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

Allocated by task 26835:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_kmalloc mm/kasan/common.c:496 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:469
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:504
 kmem_cache_alloc_trace+0x151/0x760 mm/slab.c:3609
 kmalloc include/linux/slab.h:545 [inline]
 kzalloc include/linux/slab.h:740 [inline]
 __rdma_create_id+0xce/0x630 drivers/infiniband/core/cma.c:879
 ucma_create_id+0x30f/0x910 drivers/infiniband/core/ucma.c:506
 ucma_write+0x36b/0x480 drivers/infiniband/core/ucma.c:1689
 __vfs_write+0x116/0xb40 fs/read_write.c:485
 vfs_write+0x20c/0x580 fs/read_write.c:549
 ksys_write+0x105/0x260 fs/read_write.c:598
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __ia32_sys_write+0x71/0xb0 fs/read_write.c:607
 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
 do_fast_syscall_32+0x333/0xf98 arch/x86/entry/common.c:397
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

Freed by task 26835:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:458
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:466
 __cache_free mm/slab.c:3487 [inline]
 kfree+0xcf/0x230 mm/slab.c:3806
 rdma_destroy_id+0x8be/0xd80 drivers/infiniband/core/cma.c:1849
 ucma_destroy_id+0x34c/0x540 drivers/infiniband/core/ucma.c:638
 ucma_write+0x36b/0x480 drivers/infiniband/core/ucma.c:1689
 __vfs_write+0x116/0xb40 fs/read_write.c:485
 vfs_write+0x20c/0x580 fs/read_write.c:549
 ksys_write+0x105/0x260 fs/read_write.c:598
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __ia32_sys_write+0x71/0xb0 fs/read_write.c:607
 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
 do_fast_syscall_32+0x333/0xf98 arch/x86/entry/common.c:397
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

The buggy address belongs to the object at ffff888096f38340
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 912 bytes inside of
 2048-byte region [ffff888096f38340, ffff888096f38b40)
The buggy address belongs to the page:
page:ffffea00025bce00 count:1 mapcount:0 mapping:ffff88812c3f0c40 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea0002576608 ffffea00016f3d08 ffff88812c3f0c40
raw: 0000000000000000 ffff888096f38340 0000000100000003 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888096f38580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888096f38600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888096f38680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff888096f38700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888096f38780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================