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BUG: KASAN: use-after-free in sk_psock_unlink+0x4d8/0x700 net/core/sock_map.c:993
Read of size 4 at addr ffff8881d1ff4a98 by task syz-executor2/10007

CPU: 1 PID: 10007 Comm: syz-executor2 Not tainted 4.20.0-rc2+ #333
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x244/0x39d lib/dump_stack.c:113
 print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432
 sk_psock_unlink+0x4d8/0x700 net/core/sock_map.c:993
 tcp_bpf_remove+0xd0/0x130 net/ipv4/tcp_bpf.c:512
 tcp_bpf_close+0x1c6/0x4a0 net/ipv4/tcp_bpf.c:552
 inet_release+0x104/0x1f0 net/ipv4/af_inet.c:428
 __sock_release+0xd7/0x250 net/socket.c:579
 sock_close+0x19/0x20 net/socket.c:1141
 __fput+0x385/0xa30 fs/file_table.c:278
 ____fput+0x15/0x20 fs/file_table.c:309
 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
 do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x411021
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 34 19 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007ffe2eabd460 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000411021
RDX: 0000000000000000 RSI: 0000000000732bc0 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 00007ffe2eabd390 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000001 R14: 0000000000000456 R15: 0000000000000002

Allocated by task 10014:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
 kmem_cache_alloc_trace+0x152/0x750 mm/slab.c:3620
 kmalloc include/linux/slab.h:546 [inline]
 kzalloc include/linux/slab.h:741 [inline]
 sock_hash_alloc+0x1eb/0x5a0 net/core/sock_map.c:802
 find_and_alloc_map kernel/bpf/syscall.c:129 [inline]
 map_create+0x3bd/0x1110 kernel/bpf/syscall.c:509
 __do_sys_bpf kernel/bpf/syscall.c:2489 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:2466 [inline]
 __x64_sys_bpf+0x303/0x520 kernel/bpf/syscall.c:2466
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 31598:
 save_stack+0x43/0xd0 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:3498 [inline]
 kfree+0xcf/0x230 mm/slab.c:3817
 sock_hash_free+0x450/0x640 net/core/sock_map.c:865
 bpf_map_free_deferred+0xd9/0x110 kernel/bpf/syscall.c:290
 process_one_work+0xc90/0x1c40 kernel/workqueue.c:2153
 worker_thread+0x17f/0x1390 kernel/workqueue.c:2296
 kthread+0x35a/0x440 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

The buggy address belongs to the object at ffff8881d1ff4a80
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 24 bytes inside of
 512-byte region [ffff8881d1ff4a80, ffff8881d1ff4c80)
The buggy address belongs to the page:
page:ffffea000747fd00 count:1 mapcount:0 mapping:ffff8881da800940 index:0x0
flags: 0x2fffc0000000200(slab)
raw: 02fffc0000000200 ffffea0006f75008 ffffea0006dc0c08 ffff8881da800940
raw: 0000000000000000 ffff8881d1ff4080 0000000100000006 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881d1ff4980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881d1ff4a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8881d1ff4a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff8881d1ff4b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881d1ff4b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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