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BUG: KASAN: use-after-free in tipc_send_group_bcast+0xb08/0xcf0 net/tipc/socket.c:1021
Read of size 1 at addr ffff8801d5bb1f5e by task syz-executor5/8446

CPU: 0 PID: 8446 Comm: syz-executor5 Not tainted 4.14.0-rc5+ #88
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:52
 print_address_description+0x73/0x250 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report+0x25b/0x340 mm/kasan/report.c:409
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:427
 tipc_send_group_bcast+0xb08/0xcf0 net/tipc/socket.c:1021
 __tipc_sendmsg+0xc97/0x1b20 net/tipc/socket.c:1284
 tipc_sendmsg+0x50/0x70 net/tipc/socket.c:1249
 sock_sendmsg_nosec net/socket.c:633 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:643
 ___sys_sendmsg+0x31c/0x890 net/socket.c:2049
 __sys_sendmmsg+0x1e6/0x5f0 net/socket.c:2139
 SYSC_sendmmsg net/socket.c:2170 [inline]
 SyS_sendmmsg+0x35/0x60 net/socket.c:2165
 entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x452719
RSP: 002b:00007fc40fd2dbe8 EFLAGS: 00000212 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00000000007580d8 RCX: 0000000000452719
RDX: 0000000000000004 RSI: 0000000020004f10 RDI: 0000000000000015
RBP: 00000000000003d9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020008004 R11: 0000000000000212 R12: 00000000006f3cf8
R13: 00000000ffffffff R14: 00007fc40fd2e6d4 R15: 0000000000000002

Allocated by task 8436:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
 kmem_cache_alloc_trace+0x136/0x750 mm/slab.c:3627
 kmalloc include/linux/slab.h:493 [inline]
 kzalloc include/linux/slab.h:666 [inline]
 tipc_group_create+0x116/0x9c0 net/tipc/group.c:167
 tipc_sk_join net/tipc/socket.c:2747 [inline]
 tipc_setsockopt+0x25e/0xc00 net/tipc/socket.c:2859
 SYSC_setsockopt net/socket.c:1852 [inline]
 SyS_setsockopt+0x189/0x360 net/socket.c:1831
 entry_SYSCALL_64_fastpath+0x1f/0xbe

Freed by task 8436:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xca/0x250 mm/slab.c:3820
 tipc_group_delete+0x2c0/0x3c0 net/tipc/group.c:206
 tipc_sk_join net/tipc/socket.c:2760 [inline]
 tipc_setsockopt+0xb33/0xc00 net/tipc/socket.c:2859
 SYSC_setsockopt net/socket.c:1852 [inline]
 SyS_setsockopt+0x189/0x360 net/socket.c:1831
 entry_SYSCALL_64_fastpath+0x1f/0xbe

The buggy address belongs to the object at ffff8801d5bb1f00
 which belongs to the cache kmalloc-192 of size 192
The buggy address is located 94 bytes inside of
 192-byte region [ffff8801d5bb1f00, ffff8801d5bb1fc0)
The buggy address belongs to the page:
page:ffffea000756ec40 count:1 mapcount:0 mapping:ffff8801d5bb1000 index:0x0
flags: 0x200000000000100(slab)
raw: 0200000000000100 ffff8801d5bb1000 0000000000000000 0000000100000010
raw: ffffea0007644ca0 ffffea0006ff6d60 ffff8801dac00040 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d5bb1e00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801d5bb1e80: 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8801d5bb1f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff8801d5bb1f80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8801d5bb2000: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
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