================================================================== BUG: KASAN: use-after-free in ip_check_mc_rcu+0x654/0x660 net/ipv4/igmp.c:2720 Read of size 8 at addr ffff8880193519d0 by task syz-executor.4/23726 CPU: 0 PID: 23726 Comm: syz-executor.4 Not tainted 5.12.0-rc4-next-20210322-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x141/0x1d7 lib/dump_stack.c:120 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:232 __kasan_report mm/kasan/report.c:399 [inline] kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:416 ip_check_mc_rcu+0x654/0x660 net/ipv4/igmp.c:2720 __mkroute_output net/ipv4/route.c:2380 [inline] ip_route_output_key_hash_rcu+0x1959/0x2ce0 net/ipv4/route.c:2659 ip_route_output_key_hash+0x1a4/0x2f0 net/ipv4/route.c:2487 __ip_route_output_key include/net/route.h:126 [inline] ip_route_output_flow+0x23/0x150 net/ipv4/route.c:2719 udp_sendmsg+0x1a2f/0x2730 net/ipv4/udp.c:1206 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:821 sock_sendmsg_nosec net/socket.c:654 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:674 ____sys_sendmsg+0x331/0x810 net/socket.c:2350 ___sys_sendmsg+0xf3/0x170 net/socket.c:2404 __sys_sendmmsg+0x195/0x470 net/socket.c:2490 __do_sys_sendmmsg net/socket.c:2519 [inline] __se_sys_sendmmsg net/socket.c:2516 [inline] __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2516 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x466459 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fa5ca403188 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000466459 RDX: 000000000800001d RSI: 0000000020007fc0 RDI: 0000000000000005 RBP: 00000000004bf9fb R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60 R13: 00007ffd1aee257f R14: 00007fa5ca403300 R15: 0000000000022000 Allocated by task 23726: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:428 [inline] ____kasan_kmalloc mm/kasan/common.c:507 [inline] ____kasan_kmalloc mm/kasan/common.c:466 [inline] __kasan_kmalloc+0x9b/0xd0 mm/kasan/common.c:516 kmalloc include/linux/slab.h:556 [inline] kzalloc include/linux/slab.h:686 [inline] ip_mc_add1_src net/ipv4/igmp.c:1971 [inline] ip_mc_add_src+0x7ef/0xda0 net/ipv4/igmp.c:2095 ip_mc_msfilter+0x899/0xb40 net/ipv4/igmp.c:2479 do_ip_setsockopt net/ipv4/ip_sockglue.c:1255 [inline] ip_setsockopt+0x3248/0x3a00 net/ipv4/ip_sockglue.c:1423 tcp_setsockopt+0x136/0x24a0 net/ipv4/tcp.c:3655 __sys_setsockopt+0x2db/0x610 net/socket.c:2117 __do_sys_setsockopt net/socket.c:2128 [inline] __se_sys_setsockopt net/socket.c:2125 [inline] __x64_sys_setsockopt+0xba/0x150 net/socket.c:2125 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae Freed by task 23716: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:357 ____kasan_slab_free mm/kasan/common.c:360 [inline] ____kasan_slab_free mm/kasan/common.c:325 [inline] __kasan_slab_free+0xfb/0x130 mm/kasan/common.c:368 kasan_slab_free include/linux/kasan.h:212 [inline] slab_free_hook mm/slub.c:1578 [inline] slab_free_freelist_hook+0xdf/0x240 mm/slub.c:1603 slab_free mm/slub.c:3163 [inline] kfree+0xe5/0x7f0 mm/slub.c:4230 ip_mc_del1_src+0x674/0x7f0 net/ipv4/igmp.c:1884 ip_mc_del_src.isra.0+0x3e1/0x950 net/ipv4/igmp.c:1925 ip_mc_leave_src.isra.0+0x102/0x240 net/ipv4/igmp.c:2231 ip_mc_drop_socket+0x11a/0x260 net/ipv4/igmp.c:2677 inet_release+0x97/0x280 net/ipv4/af_inet.c:418 __sock_release+0xcd/0x280 net/socket.c:599 sock_close+0x18/0x20 net/socket.c:1258 __fput+0x288/0x920 fs/file_table.c:280 task_work_run+0xdd/0x1a0 kernel/task_work.c:143 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop kernel/entry/common.c:174 [inline] exit_to_user_mode_prepare+0x249/0x250 kernel/entry/common.c:208 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x44/0xae The buggy address belongs to the object at ffff8880193519c0 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 16 bytes inside of 32-byte region [ffff8880193519c0, ffff8880193519e0) The buggy address belongs to the page: page:ffffea000064d440 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x19351 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffffea00004ebc80 0000000500000005 ffff888010841500 raw: 0000000000000000 0000000000400040 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888019351880: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc ffff888019351900: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc >ffff888019351980: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc ^ ffff888019351a00: fa fb fb fb fc fc fc fc 00 00 00 04 fc fc fc fc ffff888019351a80: 00 00 00 fc fc fc fc fc fa fb fb fb fc fc fc fc ==================================================================