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BUG: KASAN: slab-out-of-bounds in fl6_update_dst+0x2bb/0x2c0 net/ipv6/exthdrs.c:1356
Read of size 16 at addr ffff888048f464c8 by task syz-executor.2/24064

CPU: 1 PID: 24064 Comm: syz-executor.2 Not tainted 5.7.0-rc4-syzkaller #0
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+0x188/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd3/0x315 mm/kasan/report.c:382
 __kasan_report.cold+0x35/0x4d mm/kasan/report.c:511
 kasan_report+0x33/0x50 mm/kasan/common.c:625
 fl6_update_dst+0x2bb/0x2c0 net/ipv6/exthdrs.c:1356
 rawv6_sendmsg+0xd7e/0x3900 net/ipv6/raw.c:912
 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:807
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x32f/0x810 net/socket.c:2352
 ___sys_sendmsg+0x100/0x170 net/socket.c:2406
 __sys_sendmmsg+0x195/0x480 net/socket.c:2496
 __do_sys_sendmmsg net/socket.c:2525 [inline]
 __se_sys_sendmmsg net/socket.c:2522 [inline]
 __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2522
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45c829
Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fd18ba3ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00000000004fc320 RCX: 000000000045c829
RDX: 0400000000000107 RSI: 0000000020008440 RDI: 0000000000000003
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000008dd R14: 00000000004cb81f R15: 00007fd18ba3f6d4

Allocated by task 24064:
 save_stack+0x1b/0x40 mm/kasan/common.c:49
 set_track mm/kasan/common.c:57 [inline]
 __kasan_kmalloc mm/kasan/common.c:495 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:468
 __do_kmalloc mm/slab.c:3656 [inline]
 __kmalloc+0x161/0x7a0 mm/slab.c:3665
 kmalloc include/linux/slab.h:560 [inline]
 sock_kmalloc net/core/sock.c:2174 [inline]
 sock_kmalloc+0xb5/0x100 net/core/sock.c:2165
 ipv6_renew_options+0x274/0x940 net/ipv6/exthdrs.c:1275
 do_ipv6_setsockopt.isra.0+0x2ea7/0x42e0 net/ipv6/ipv6_sockglue.c:435
 ipv6_setsockopt+0xfb/0x180 net/ipv6/ipv6_sockglue.c:949
 rawv6_setsockopt+0x55/0x140 net/ipv6/raw.c:1081
 __sys_setsockopt+0x248/0x480 net/socket.c:2127
 __do_sys_setsockopt net/socket.c:2143 [inline]
 __se_sys_setsockopt net/socket.c:2140 [inline]
 __x64_sys_setsockopt+0xba/0x150 net/socket.c:2140
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3

Freed by task 22670:
 save_stack+0x1b/0x40 mm/kasan/common.c:49
 set_track mm/kasan/common.c:57 [inline]
 kasan_set_free_info mm/kasan/common.c:317 [inline]
 __kasan_slab_free+0xf7/0x140 mm/kasan/common.c:456
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x109/0x2b0 mm/slab.c:3757
 ma_put net/ipv6/mcast.c:846 [inline]
 ma_put+0x105/0x160 net/ipv6/mcast.c:842
 __ipv6_dev_mc_dec+0x1fd/0x300 net/ipv6/mcast.c:961
 ipv6_mc_destroy_dev+0x31/0x160 net/ipv6/mcast.c:2611
 addrconf_ifdown+0xd8c/0x12f0 net/ipv6/addrconf.c:3826
 addrconf_notify+0x5a6/0x2270 net/ipv6/addrconf.c:3617
 notifier_call_chain+0xc0/0x230 kernel/notifier.c:83
 call_netdevice_notifiers_info net/core/dev.c:2016 [inline]
 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:2001
 call_netdevice_notifiers_extack net/core/dev.c:2028 [inline]
 call_netdevice_notifiers net/core/dev.c:2042 [inline]
 rollback_registered_many+0x75c/0xe70 net/core/dev.c:8925
 rollback_registered+0xf2/0x1c0 net/core/dev.c:8970
 unregister_netdevice_queue net/core/dev.c:10055 [inline]
 unregister_netdevice_queue+0x1d7/0x2b0 net/core/dev.c:10048
 unregister_netdevice include/linux/netdevice.h:2748 [inline]
 hsr_dev_finalize+0x5ce/0x746 net/hsr/hsr_device.c:502
 hsr_newlink+0x27c/0x520 net/hsr/hsr_netlink.c:83
 __rtnl_newlink+0xf18/0x1590 net/core/rtnetlink.c:3340
 rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3398
 rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5461
 netlink_rcv_skb+0x15a/0x410 net/netlink/af_netlink.c:2469
 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
 netlink_unicast+0x537/0x740 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0x882/0xe10 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x6e6/0x810 net/socket.c:2352
 ___sys_sendmsg+0x100/0x170 net/socket.c:2406
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2439
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3

The buggy address belongs to the object at ffff888048f46400
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 200 bytes inside of
 256-byte region [ffff888048f46400, ffff888048f46500)
The buggy address belongs to the page:
page:ffffea000123d180 refcount:1 mapcount:0 mapping:00000000c30eeddd index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea000183c0c8 ffffea00018441c8 ffff8880aa0008c0
raw: 0000000000000000 ffff888048f46000 0000000100000008 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888048f46380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888048f46400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888048f46480: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
                                              ^
 ffff888048f46500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888048f46580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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