syzbot

tipc: TX() has been purged, node left!
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BUG: KASAN: use-after-free in afs_wake_up_async_call+0x430/0x4a0 fs/afs/rxrpc.c:707
Write of size 1 at addr ffff8880938241e4 by task kworker/u4:1/21

CPU: 1 PID: 21 Comm: kworker/u4:1 Not tainted 5.8.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x18f/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x436 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 afs_wake_up_async_call+0x430/0x4a0 fs/afs/rxrpc.c:707
 rxrpc_notify_socket+0x1db/0x5d0 net/rxrpc/recvmsg.c:40
 __rxrpc_set_call_completion.part.0+0x172/0x410 net/rxrpc/recvmsg.c:76
 __rxrpc_set_call_completion net/rxrpc/recvmsg.c:112 [inline]
 __rxrpc_call_completed net/rxrpc/recvmsg.c:102 [inline]
 __rxrpc_call_completed net/rxrpc/recvmsg.c:100 [inline]
 rxrpc_call_completed+0xd0/0xf0 net/rxrpc/recvmsg.c:111
 rxrpc_discard_prealloc+0x777/0xab0 net/rxrpc/call_accept.c:233
 rxrpc_listen+0x11c/0x330 net/rxrpc/af_rxrpc.c:245
 afs_close_socket+0x95/0x320 fs/afs/rxrpc.c:110
 afs_net_exit+0x1bc/0x310 fs/afs/main.c:155
 ops_exit_list+0xb0/0x160 net/core/net_namespace.c:186
 cleanup_net+0x4ea/0xa00 net/core/net_namespace.c:603
 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Allocated by task 6823:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:494
 kmem_cache_alloc_trace+0x14f/0x2d0 mm/slab.c:3551
 kmalloc include/linux/slab.h:555 [inline]
 kzalloc include/linux/slab.h:669 [inline]
 afs_alloc_call+0x4f/0x360 fs/afs/rxrpc.c:141
 afs_charge_preallocation+0xe9/0x2d0 fs/afs/rxrpc.c:757
 afs_open_socket+0x294/0x360 fs/afs/rxrpc.c:92
 afs_net_init+0xa6c/0xe30 fs/afs/main.c:125
 ops_init+0xaf/0x470 net/core/net_namespace.c:151
 setup_net+0x2d8/0x850 net/core/net_namespace.c:341
 copy_net_ns+0x2cf/0x5e0 net/core/net_namespace.c:482
 create_new_namespaces+0x3f6/0xb10 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xbd/0x1f0 kernel/nsproxy.c:231
 ksys_unshare+0x36c/0x9a0 kernel/fork.c:2983
 __do_sys_unshare kernel/fork.c:3051 [inline]
 __se_sys_unshare kernel/fork.c:3049 [inline]
 __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3049
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 21:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0xf5/0x140 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x103/0x2c0 mm/slab.c:3757
 afs_put_call+0x345/0x440 fs/afs/rxrpc.c:190
 rxrpc_discard_prealloc+0x75a/0xab0 net/rxrpc/call_accept.c:230
 rxrpc_listen+0x11c/0x330 net/rxrpc/af_rxrpc.c:245
 afs_close_socket+0x95/0x320 fs/afs/rxrpc.c:110
 afs_net_exit+0x1bc/0x310 fs/afs/main.c:155
 ops_exit_list+0xb0/0x160 net/core/net_namespace.c:186
 cleanup_net+0x4ea/0xa00 net/core/net_namespace.c:603
 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

The buggy address belongs to the object at ffff888093824000
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 484 bytes inside of
 1024-byte region [ffff888093824000, ffff888093824400)
The buggy address belongs to the page:
page:ffffea00024e0900 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00027d41c8 ffffea00028a0388 ffff8880aa000c40
raw: 0000000000000000 ffff888093824000 0000000100000002 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888093824080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888093824100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888093824180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                       ^
 ffff888093824200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888093824280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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