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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:228 [inline]
BUG: KASAN: use-after-free in rds_destroy_pending net/rds/rds.h:868 [inline]
BUG: KASAN: use-after-free in rds_queue_reconnect+0x434/0x990 net/rds/threads.c:152
Read of size 4 at addr ffff880194812104 by task kworker/u4:0/6

CPU: 0 PID: 6 Comm: kworker/u4:0 Not tainted 4.16.0+ #288
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: krdsd rds_connect_worker
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1a7/0x27d lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report+0x23c/0x360 mm/kasan/report.c:412
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x137/0x190 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:228 [inline]
 rds_destroy_pending net/rds/rds.h:868 [inline]
 rds_queue_reconnect+0x434/0x990 net/rds/threads.c:152
 rds_connect_worker+0x1cd/0x210 net/rds/threads.c:183
 process_one_work+0xc97/0x1c40 kernel/workqueue.c:2113
 worker_thread+0x1c3/0x1380 kernel/workqueue.c:2247
 kthread+0x33c/0x400 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411

Allocated by task 4531:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:552
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3542
 kmem_cache_zalloc include/linux/slab.h:691 [inline]
 net_alloc net/core/net_namespace.c:369 [inline]
 copy_net_ns+0x152/0x5c0 net/core/net_namespace.c:409
 create_new_namespaces+0x432/0x890 kernel/nsproxy.c:107
 unshare_nsproxy_namespaces+0xae/0x1e0 kernel/nsproxy.c:206
 ksys_unshare+0x68a/0xe90 kernel/fork.c:2407
 SYSC_unshare kernel/fork.c:2475 [inline]
 SyS_unshare+0x15/0x20 kernel/fork.c:2473
 do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline]
 do_fast_syscall_32+0x3ec/0xf9f arch/x86/entry/common.c:392
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

Freed by task 6:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:520
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527
 __cache_free mm/slab.c:3486 [inline]
 kmem_cache_free+0x83/0x2a0 mm/slab.c:3744
 net_free+0xca/0x110 net/core/net_namespace.c:385
 net_drop_ns.part.12+0x26/0x30 net/core/net_namespace.c:392
 net_drop_ns net/core/net_namespace.c:391 [inline]
 cleanup_net+0x988/0xcd0 net/core/net_namespace.c:535
 process_one_work+0xc97/0x1c40 kernel/workqueue.c:2113
 worker_thread+0x1c3/0x1380 kernel/workqueue.c:2247
 kthread+0x33c/0x400 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411

The buggy address belongs to the object at ffff880194812100
 which belongs to the cache net_namespace of size 6848
The buggy address is located 4 bytes inside of
 6848-byte region [ffff880194812100, ffff880194813bc0)
The buggy address belongs to the page:
page:ffffea0006520480 count:1 mapcount:0 mapping:ffff880194812100 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffff880194812100 0000000000000000 0000000100000001
raw: ffffea000653a320 ffffea00064e6f20 ffff8801d9fbee00 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff880194812000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff880194812080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff880194812100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff880194812180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff880194812200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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