sshd (5974) used greatest stack depth: 15440 bytes left
==================================================================
BUG: KASAN: use-after-free in tipc_group_bc_cong+0x327/0x3f0 net/tipc/group.c:448
Read of size 2 at addr ffff8881d9069d74 by task syz-executor912/5991

CPU: 1 PID: 5991 Comm: syz-executor912 Not tainted 4.20.0-rc6+ #274
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_load2_noabort+0x14/0x20 mm/kasan/report.c:431
 tipc_group_bc_cong+0x327/0x3f0 net/tipc/group.c:448
 tipc_send_group_bcast+0x50a/0xd90 net/tipc/socket.c:1023
 __tipc_sendmsg+0xeec/0x1d40 net/tipc/socket.c:1307
 tipc_sendmsg+0x50/0x70 net/tipc/socket.c:1272
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:631
 ___sys_sendmsg+0x7fd/0x930 net/socket.c:2116
 __sys_sendmsg+0x11d/0x280 net/socket.c:2154
 __compat_sys_sendmsg net/compat.c:754 [inline]
 __do_compat_sys_sendmsg net/compat.c:761 [inline]
 __se_compat_sys_sendmsg net/compat.c:758 [inline]
 __ia32_compat_sys_sendmsg+0x7a/0xb0 net/compat.c:758
 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
 do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7feea29
Code: 85 d2 74 02 89 0a 5b 5d c3 8b 04 24 c3 8b 14 24 c3 8b 3c 24 c3 90 90 90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000f7fea1fc EFLAGS: 00000297 ORIG_RAX: 0000000000000172
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000200001c0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00000000003d0f00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 5991:
 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]
 tipc_group_create+0x152/0xa70 net/tipc/group.c:171
 tipc_sk_join net/tipc/socket.c:2829 [inline]
 tipc_setsockopt+0x2d1/0xd70 net/tipc/socket.c:2944
 __compat_sys_setsockopt+0x329/0x860 net/compat.c:407
 __do_compat_sys_setsockopt net/compat.c:417 [inline]
 __se_compat_sys_setsockopt net/compat.c:414 [inline]
 __ia32_compat_sys_setsockopt+0xbd/0x150 net/compat.c:414
 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
 do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

Freed by task 5992:
 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
 tipc_group_delete+0x2e4/0x3f0 net/tipc/group.c:227
 tipc_sk_leave+0x113/0x220 net/tipc/socket.c:2863
 tipc_setsockopt+0x97d/0xd70 net/tipc/socket.c:2947
 __compat_sys_setsockopt+0x329/0x860 net/compat.c:407
 __do_compat_sys_setsockopt net/compat.c:417 [inline]
 __se_compat_sys_setsockopt net/compat.c:414 [inline]
 __ia32_compat_sys_setsockopt+0xbd/0x150 net/compat.c:414
 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
 do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

The buggy address belongs to the object at ffff8881d9069d00
 which belongs to the cache kmalloc-192 of size 192
The buggy address is located 116 bytes inside of
 192-byte region [ffff8881d9069d00, ffff8881d9069dc0)
The buggy address belongs to the page:
page:ffffea0007641a40 count:1 mapcount:0 mapping:ffff8881da800040 index:0x0
flags: 0x2fffc0000000200(slab)
raw: 02fffc0000000200 ffffea000717b048 ffffea0007615e08 ffff8881da800040
raw: 0000000000000000 ffff8881d9069000 0000000100000010 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881d9069c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881d9069c80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff8881d9069d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                             ^
 ffff8881d9069d80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8881d9069e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================