sshd (6084) used greatest stack depth: 16296 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 ffff8881d882d774 by task syz-executor113/6103 CPU: 0 PID: 6103 Comm: syz-executor113 Not tainted 4.20.0-rc6-next-20181213+ #170 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.4+0x9/0x1ff mm/kasan/report.c:187 kasan_report.cold.5+0x1b/0x39 mm/kasan/report.c:317 __asan_report_load2_noabort+0x14/0x20 mm/kasan/generic_report.c:133 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:622 [inline] sock_sendmsg+0xd5/0x120 net/socket.c:632 ___sys_sendmsg+0x7fd/0x930 net/socket.c:2117 __sys_sendmsg+0x11d/0x280 net/socket.c:2155 __do_sys_sendmsg net/socket.c:2164 [inline] __se_sys_sendmsg net/socket.c:2162 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2162 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x446389 Code: e8 2c b3 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 2b 09 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007faaade0fdb8 EFLAGS: 00000297 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00000000006dac38 RCX: 0000000000446389 RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 0000000000000005 RBP: 00000000006dac30 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000297 R12: 00000000006dac3c R13: 00007ffca0f14eef R14: 00007faaade109c0 R15: 00000000006dad2c Allocated by task 6104: save_stack+0x43/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] kasan_kmalloc+0xcb/0xd0 mm/kasan/common.c:482 kmem_cache_alloc_trace+0x154/0x740 mm/slab.c:3607 kmalloc include/linux/slab.h:545 [inline] kzalloc include/linux/slab.h:740 [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 __sys_setsockopt+0x1ba/0x3c0 net/socket.c:1903 __do_sys_setsockopt net/socket.c:1914 [inline] __se_sys_setsockopt net/socket.c:1911 [inline] __x64_sys_setsockopt+0xbe/0x150 net/socket.c:1911 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 6104: save_stack+0x43/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:444 kasan_slab_free+0xe/0x10 mm/kasan/common.c:452 __cache_free mm/slab.c:3485 [inline] kfree+0xcf/0x230 mm/slab.c:3804 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 __sys_setsockopt+0x1ba/0x3c0 net/socket.c:1903 __do_sys_setsockopt net/socket.c:1914 [inline] __se_sys_setsockopt net/socket.c:1911 [inline] __x64_sys_setsockopt+0xbe/0x150 net/socket.c:1911 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8881d882d700 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 116 bytes inside of 192-byte region [ffff8881d882d700, ffff8881d882d7c0) The buggy address belongs to the page: page:ffffea0007620b40 count:1 mapcount:0 mapping:ffff8881da800040 index:0xffff8881d882df00 flags: 0x2fffc0000000200(slab) raw: 02fffc0000000200 ffffea0007620e48 ffffea0007621388 ffff8881da800040 raw: ffff8881d882df00 ffff8881d882d000 0000000100000009 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881d882d600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881d882d680: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >ffff8881d882d700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881d882d780: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff8881d882d800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================