syzbot

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BUG: KASAN: use-after-free in sk_psock_unlink+0x3dd/0x4b0 net/core/sock_map.c:988
Read of size 4 at addr ffff888099466a98 by task syz-executor.2/23870

CPU: 1 PID: 23870 Comm: syz-executor.2 Not tainted 5.2.0-rc6-next-20190624 #21
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+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0xd4/0x306 mm/kasan/report.c:351
 __kasan_report.cold+0x1b/0x36 mm/kasan/report.c:482
 kasan_report+0x12/0x20 mm/kasan/common.c:614
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:131
 sk_psock_unlink+0x3dd/0x4b0 net/core/sock_map.c:988
 tcp_bpf_remove+0x21/0x50 net/ipv4/tcp_bpf.c:535
 tcp_bpf_close+0x130/0x390 net/ipv4/tcp_bpf.c:575
 inet_release+0xed/0x200 net/ipv4/af_inet.c:427
 inet6_release+0x53/0x80 net/ipv6/af_inet6.c:470
 __sock_release+0xce/0x2a0 net/socket.c:601
 sock_close+0x1b/0x30 net/socket.c:1273
 __fput+0x2ff/0x890 fs/file_table.c:280
 ____fput+0x16/0x20 fs/file_table.c:313
 task_work_run+0x145/0x1c0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x280/0x2d0 arch/x86/entry/common.c:168
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:279 [inline]
 do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:304
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x413201
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 04 1b 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:00007fffddcda890 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000006 RCX: 0000000000413201
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 0000000000000001 R08: ffffffffffffffff R09: ffffffffffffffff
R10: 00007fffddcda970 R11: 0000000000000293 R12: 00000000007610a8
R13: 000000000007b92a R14: 000000000007b957 R15: ffffffffffffffff

Allocated by task 23871:
 save_stack+0x23/0x90 mm/kasan/common.c:71
 set_track mm/kasan/common.c:79 [inline]
 __kasan_kmalloc mm/kasan/common.c:489 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:462
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:503
 kmem_cache_alloc_trace+0x158/0x790 mm/slab.c:3550
 kmalloc include/linux/slab.h:547 [inline]
 kzalloc include/linux/slab.h:743 [inline]
 sock_map_alloc net/core/sock_map.c:38 [inline]
 sock_map_alloc+0x1bb/0x3a0 net/core/sock_map.c:24
 find_and_alloc_map kernel/bpf/syscall.c:121 [inline]
 map_create kernel/bpf/syscall.c:569 [inline]
 __do_sys_bpf+0x475/0x42f0 kernel/bpf/syscall.c:2812
 __se_sys_bpf kernel/bpf/syscall.c:2789 [inline]
 __x64_sys_bpf+0x73/0xb0 kernel/bpf/syscall.c:2789
 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 9190:
 save_stack+0x23/0x90 mm/kasan/common.c:71
 set_track mm/kasan/common.c:79 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:451
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:459
 __cache_free mm/slab.c:3425 [inline]
 kfree+0x10a/0x2c0 mm/slab.c:3756
 sock_map_free+0x22a/0x310 net/core/sock_map.c:251
 bpf_map_free_deferred+0xb3/0x100 kernel/bpf/syscall.c:307
 process_one_work+0x9af/0x1740 kernel/workqueue.c:2269
 worker_thread+0x98/0xe40 kernel/workqueue.c:2415
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:353

The buggy address belongs to the object at ffff888099466a80
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 24 bytes inside of
 512-byte region [ffff888099466a80, ffff888099466c80)
The buggy address belongs to the page:
page:ffffea0002651980 refcount:1 mapcount:0 mapping:ffff8880aa400a80 index:0xffff888099466800
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea000266cb88 ffffea00025e83c8 ffff8880aa400a80
raw: ffff888099466800 ffff888099466080 0000000100000003 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888099466980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888099466a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888099466a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff888099466b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888099466b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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