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BUG: KASAN: use-after-free in kernel_accept+0x2a4/0x310 net/socket.c:3246
Read of size 8 at addr ffff88017a9e0628 by task kworker/1:2/3114

CPU: 1 PID: 3114 Comm: kworker/1:2 Not tainted 4.19.0-rc8-next-20181019+ #98
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events smc_tcp_listen_work
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_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 kernel_accept+0x2a4/0x310 net/socket.c:3246
 smc_clcsock_accept net/smc/af_smc.c:834 [inline]
 smc_tcp_listen_work+0x218/0x11c0 net/smc/af_smc.c:1302
 process_one_work+0xc8b/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

Allocated by task 7983:
 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
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490
 kmem_cache_alloc+0x12e/0x730 mm/slab.c:3554
 sock_alloc_inode+0x1d/0x260 net/socket.c:244
 alloc_inode+0x63/0x190 fs/inode.c:210
 new_inode_pseudo+0x71/0x1a0 fs/inode.c:903
 sock_alloc+0x41/0x270 net/socket.c:548
 __sock_create+0x175/0x930 net/socket.c:1242
 sock_create_kern+0x3b/0x50 net/socket.c:1324
 smc_create+0x17c/0x3b0 net/smc/af_smc.c:1907
 __sock_create+0x536/0x930 net/socket.c:1278
 sock_create net/socket.c:1318 [inline]
 __sys_socket+0x106/0x260 net/socket.c:1348
 __do_sys_socket net/socket.c:1357 [inline]
 __se_sys_socket net/socket.c:1355 [inline]
 __x64_sys_socket+0x73/0xb0 net/socket.c:1355
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 7981:
 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]
 kmem_cache_free+0x83/0x290 mm/slab.c:3760
 sock_destroy_inode+0x51/0x60 net/socket.c:272
 destroy_inode+0x159/0x200 fs/inode.c:267
 evict+0x5e0/0x980 fs/inode.c:575
 iput_final fs/inode.c:1547 [inline]
 iput+0x674/0xa90 fs/inode.c:1573
 __sock_release+0x1ec/0x250 net/socket.c:591
 sock_release+0x17/0x20 net/socket.c:599
 smc_release+0x1a8/0x730 net/smc/af_smc.c:148
 __sock_release+0xd7/0x250 net/socket.c:580
 sock_close+0x19/0x20 net/socket.c:1142
 __fput+0x3bc/0xa70 fs/file_table.c:279
 ____fput+0x15/0x20 fs/file_table.c:312
 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

The buggy address belongs to the object at ffff88017a9e0600
 which belongs to the cache sock_inode_cache(49:syz2) of size 976
The buggy address is located 40 bytes inside of
 976-byte region [ffff88017a9e0600, ffff88017a9e09d0)
The buggy address belongs to the page:
page:ffffea0005ea7800 count:1 mapcount:0 mapping:ffff8801c27476c0 index:0xffff88017a9e0ffd
flags: 0x2fffc0000000200(slab)
raw: 02fffc0000000200 ffffea0007138488 ffffea0005ea7fc8 ffff8801c27476c0
raw: ffff88017a9e0ffd ffff88017a9e0180 0000000100000003 ffff880185d70900
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff880185d70900

Memory state around the buggy address:
 ffff88017a9e0500: fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc
 ffff88017a9e0580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88017a9e0600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff88017a9e0680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88017a9e0700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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