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BUG: KASAN: use-after-free in rxrpc_send_keepalive+0x83e/0x8e0 net/rxrpc/output.c:637
Read of size 8 at addr ffff88808fbd3698 by task kworker/0:3/7599

CPU: 0 PID: 7599 Comm: kworker/0:3 Not tainted 4.19.81 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: krxrpcd rxrpc_peer_keepalive_worker
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report mm/kasan/report.c:412 [inline]
 kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:396
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 rxrpc_send_keepalive+0x83e/0x8e0 net/rxrpc/output.c:637
 rxrpc_peer_keepalive_dispatch net/rxrpc/peer_event.c:366 [inline]
 rxrpc_peer_keepalive_worker+0x7be/0xd02 net/rxrpc/peer_event.c:427
 process_one_work+0x989/0x1750 kernel/workqueue.c:2153
 worker_thread+0x98/0xe40 kernel/workqueue.c:2296
 kthread+0x354/0x420 kernel/kthread.c:246
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

Allocated by task 16794:
 save_stack+0x45/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc mm/kasan/kasan.c:553 [inline]
 kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:531
 kmem_cache_alloc_trace+0x152/0x760 mm/slab.c:3625
 kmalloc include/linux/slab.h:515 [inline]
 kzalloc include/linux/slab.h:709 [inline]
 rxrpc_alloc_local net/rxrpc/local_object.c:83 [inline]
 rxrpc_lookup_local+0x562/0x1b70 net/rxrpc/local_object.c:281
 rxrpc_sendmsg+0x36f/0x5b0 net/rxrpc/af_rxrpc.c:573
 sock_sendmsg_nosec net/socket.c:622 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:632
 ___sys_sendmsg+0x3e2/0x920 net/socket.c:2115
 __sys_sendmmsg+0x1bf/0x4e0 net/socket.c:2210
 __do_sys_sendmmsg net/socket.c:2239 [inline]
 __se_sys_sendmmsg net/socket.c:2236 [inline]
 __x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2236
 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 7572:
 save_stack+0x45/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xcf/0x220 mm/slab.c:3822
 rxrpc_local_rcu+0x53/0x60 net/rxrpc/local_object.c:500
 __rcu_reclaim kernel/rcu/rcu.h:236 [inline]
 rcu_do_batch kernel/rcu/tree.c:2584 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2897 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2864 [inline]
 rcu_process_callbacks+0xba0/0x1a30 kernel/rcu/tree.c:2881
 __do_softirq+0x25c/0x921 kernel/softirq.c:292

The buggy address belongs to the object at ffff88808fbd3680
 which belongs to the cache kmalloc-1024 of size 1024
The buggy address is located 24 bytes inside of
 1024-byte region [ffff88808fbd3680, ffff88808fbd3a80)
The buggy address belongs to the page:
page:ffffea00023ef480 count:1 mapcount:0 mapping:ffff88812c3f0ac0 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000008100(slab|head)
raw: 01fffc0000008100 ffffea0002693708 ffffea000262de08 ffff88812c3f0ac0
raw: 0000000000000000 ffff88808fbd2000 0000000100000007 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808fbd3580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808fbd3600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88808fbd3680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88808fbd3700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808fbd3780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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