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BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
BUG: KASAN: use-after-free in refcount_read include/linux/refcount.h:42 [inline]
BUG: KASAN: use-after-free in check_net include/net/net_namespace.h:236 [inline]
BUG: KASAN: use-after-free in rds_destroy_pending net/rds/rds.h:902 [inline]
BUG: KASAN: use-after-free in rds_cong_queue_updates+0x25d/0x5b0 net/rds/cong.c:226
Read of size 4 at addr ffff8801d909c404 by task kworker/u4:4/19208

CPU: 0 PID: 19208 Comm: kworker/u4:4 Not tainted 4.18.0-rc3+ #127
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: krdsd rds_send_worker
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113
 print_address_description+0x6c/0x20b mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
 kasan_check_read+0x11/0x20 mm/kasan/kasan.c:272
 atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
 refcount_read include/linux/refcount.h:42 [inline]
 check_net include/net/net_namespace.h:236 [inline]
 rds_destroy_pending net/rds/rds.h:902 [inline]
 rds_cong_queue_updates+0x25d/0x5b0 net/rds/cong.c:226
 rds_recv_rcvbuf_delta.part.3+0x332/0x3e0 net/rds/recv.c:123
 rds_recv_rcvbuf_delta net/rds/recv.c:382 [inline]
 rds_recv_incoming+0x85a/0x1320 net/rds/recv.c:382
 rds_loop_xmit+0x16a/0x340 net/rds/loop.c:82
 rds_send_xmit+0x1343/0x29c0 net/rds/send.c:355
 rds_send_worker+0x153/0x300 net/rds/threads.c:199
 process_one_work+0xc73/0x1ba0 kernel/workqueue.c:2153
 worker_thread+0x189/0x13c0 kernel/workqueue.c:2296
 kthread+0x345/0x410 kernel/kthread.c:240
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412

Allocated by task 21536:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553
 __do_kmalloc mm/slab.c:3718 [inline]
 __kmalloc_track_caller+0x14a/0x760 mm/slab.c:3733
 kstrdup+0x39/0x70 mm/util.c:56
 kstrdup_const+0x66/0x80 mm/util.c:77
 alloc_vfsmnt+0x1bb/0x9f0 fs/namespace.c:214
 clone_mnt+0x124/0x14a0 fs/namespace.c:1077
 copy_tree+0x485/0xb00 fs/namespace.c:1806
 propagate_one+0x4e3/0x930 fs/pnode.c:265
 propagate_mnt+0x18a/0x3e0 fs/pnode.c:315
 attach_recursive_mnt+0x60c/0xb70 fs/namespace.c:2033
 graft_tree+0x1aa/0x240 fs/namespace.c:2133
 do_loopback fs/namespace.c:2254 [inline]
 do_mount+0x279a/0x30e0 fs/namespace.c:2842
 ksys_mount+0x12d/0x140 fs/namespace.c:3064
 __do_sys_mount fs/namespace.c:3078 [inline]
 __se_sys_mount fs/namespace.c:3075 [inline]
 __x64_sys_mount+0xbe/0x150 fs/namespace.c:3075
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 0:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kfree+0xd9/0x260 mm/slab.c:3813
 kfree_const+0x59/0x70 mm/util.c:38
 free_vfsmnt+0x37/0x80 fs/namespace.c:640
 delayed_free_vfsmnt+0x16/0x20 fs/namespace.c:649
 __rcu_reclaim kernel/rcu/rcu.h:178 [inline]
 rcu_do_batch kernel/rcu/tree.c:2558 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2818 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2785 [inline]
 rcu_process_callbacks+0xed5/0x1850 kernel/rcu/tree.c:2802
 __do_softirq+0x2e8/0xb17 kernel/softirq.c:288

The buggy address belongs to the object at ffff8801d909c400
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 4 bytes inside of
 32-byte region [ffff8801d909c400, ffff8801d909c420)
The buggy address belongs to the page:
page:ffffea0007642700 count:1 mapcount:0 mapping:ffff8801da8001c0 index:0xffff8801d909cfc1
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffffea00059116c8 ffffea00064c6048 ffff8801da8001c0
raw: ffff8801d909cfc1 ffff8801d909c000 000000010000003f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d909c300: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801d909c380: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8801d909c400: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
                   ^
 ffff8801d909c480: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801d909c500: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
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