==================================================================
BUG: KASAN: use-after-free in ip_check_mc_rcu+0x654/0x660 net/ipv4/igmp.c:2720
Read of size 8 at addr ffff888021465a90 by task syz-executor.2/13276

CPU: 2 PID: 13276 Comm: syz-executor.2 Not tainted 5.11.0-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0xfa/0x151 lib/dump_stack.c:120
 print_address_description.constprop.0.cold+0x5b/0x2c6 mm/kasan/report.c:230
 __kasan_report mm/kasan/report.c:397 [inline]
 kasan_report.cold+0x79/0xd5 mm/kasan/report.c:414
 ip_check_mc_rcu+0x654/0x660 net/ipv4/igmp.c:2720
 __mkroute_output net/ipv4/route.c:2405 [inline]
 ip_route_output_key_hash_rcu+0x1959/0x2ce0 net/ipv4/route.c:2684
 ip_route_output_key_hash+0x1a4/0x2f0 net/ipv4/route.c:2512
 __ip_route_output_key include/net/route.h:126 [inline]
 ip_route_output_flow+0x23/0x150 net/ipv4/route.c:2773
 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:2494
 __do_sys_sendmmsg net/socket.c:2523 [inline]
 __se_sys_sendmmsg net/socket.c:2520 [inline]
 __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2520
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x465ef9
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:00007f8c1414e188 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 000000000056c008 RCX: 0000000000465ef9
RDX: 000000000800001d RSI: 0000000020007fc0 RDI: 0000000000000003
RBP: 00000000004bcd1c R08: 0000000000000000 R09: 0000000000000000
R10: 00000000000001f4 R11: 0000000000000246 R12: 000000000056c008
R13: 00007ffc06d4f14f R14: 00007f8c1414e300 R15: 0000000000022000

Allocated by task 13269:
 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:400 [inline]
 ____kasan_kmalloc.constprop.0+0x7f/0xa0 mm/kasan/common.c:428
 kasan_kmalloc include/linux/kasan.h:218 [inline]
 kmem_cache_alloc_trace+0x1d8/0x3f0 mm/slab.c:3553
 kmalloc include/linux/slab.h:554 [inline]
 kzalloc include/linux/slab.h:684 [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+0x136/0x2440 net/ipv4/tcp.c:3636
 __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 13267:
 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:356
 ____kasan_slab_free+0xb0/0xe0 mm/kasan/common.c:361
 kasan_slab_free include/linux/kasan.h:191 [inline]
 __cache_free mm/slab.c:3423 [inline]
 kfree+0xe9/0x260 mm/slab.c:3779
 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:140
 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+0x19/0x50 kernel/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x44/0xae

The buggy address belongs to the object at ffff888021465a80
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 16 bytes inside of
 32-byte region [ffff888021465a80, ffff888021465aa0)
The buggy address belongs to the page:
page:00000000e566dfda refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888021465fc1 pfn:0x21465
flags: 0xfff00000000200(slab)
raw: 00fff00000000200 ffffea00008415c8 ffff888010c41240 ffff888010c40100
raw: ffff888021465fc1 ffff888021465000 000000010000003d 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888021465980: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
 ffff888021465a00: fa fb fb fb fc fc fc fc 00 00 00 04 fc fc fc fc
>ffff888021465a80: fa fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
                         ^
 ffff888021465b00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff888021465b80: fb fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
==================================================================