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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 ffff88809a9fda88 by task syz-executor.1/2760

CPU: 1 PID: 2760 Comm: syz-executor.1 Not tainted 5.7.0-rc7-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+0xd3/0x413 mm/kasan/report.c:382
 __kasan_report.cold+0x20/0x38 mm/kasan/report.c:511
 kasan_report+0x33/0x50 mm/kasan/common.c:625
 fl6_update_dst+0x2bb/0x2c0 net/ipv6/exthdrs.c:1356
 sctp_v6_get_dst+0x5e7/0x1c30 net/sctp/ipv6.c:276
 sctp_transport_route+0x125/0x350 net/sctp/transport.c:297
 sctp_assoc_add_peer+0x5a0/0x1030 net/sctp/associola.c:659
 sctp_connect_new_asoc+0x19b/0x580 net/sctp/socket.c:1092
 __sctp_connect+0x430/0xc70 net/sctp/socket.c:1190
 sctp_connect net/sctp/socket.c:4908 [inline]
 sctp_inet_connect+0x14b/0x1b0 net/sctp/socket.c:4923
 __sys_connect_file+0x155/0x1a0 net/socket.c:1859
 __sys_connect+0x160/0x190 net/socket.c:1876
 __do_sys_connect net/socket.c:1887 [inline]
 __se_sys_connect net/socket.c:1884 [inline]
 __x64_sys_connect+0x6f/0xb0 net/socket.c:1884
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45ca29
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:00007f5ef92f2c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00000000004daf40 RCX: 000000000045ca29
RDX: 000000000000001c RSI: 0000000020000080 RDI: 0000000000000005
RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000084 R14: 00000000004c33c2 R15: 00007f5ef92f36d4

Allocated by task 2760:
 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:2166 [inline]
 sock_kmalloc+0xb5/0x100 net/core/sock.c:2157
 ipv6_renew_options+0x274/0x940 net/ipv6/exthdrs.c:1275
 do_ipv6_setsockopt.isra.0+0x2eaf/0x42f0 net/ipv6/ipv6_sockglue.c:435
 ipv6_setsockopt+0xfb/0x180 net/ipv6/ipv6_sockglue.c:949
 sctp_setsockopt+0x13e/0x7090 net/sctp/socket.c:4685
 __sys_setsockopt+0x248/0x480 net/socket.c:2132
 __do_sys_setsockopt net/socket.c:2148 [inline]
 __se_sys_setsockopt net/socket.c:2145 [inline]
 __x64_sys_setsockopt+0xba/0x150 net/socket.c:2145
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3

Freed by task 2371:
 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
 call_usermodehelper_freeinfo kernel/umh.c:48 [inline]
 umh_complete kernel/umh.c:62 [inline]
 umh_complete+0x81/0x90 kernel/umh.c:51
 call_usermodehelper_exec_async+0x45f/0x710 kernel/umh.c:122
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351

The buggy address belongs to the object at ffff88809a9fda00
 which belongs to the cache kmalloc-192 of size 192
The buggy address is located 136 bytes inside of
 192-byte region [ffff88809a9fda00, ffff88809a9fdac0)
The buggy address belongs to the page:
page:ffffea00026a7f40 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88809a9fd600
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea000268ed08 ffffea0002877d08 ffff8880aa000000
raw: ffff88809a9fd600 ffff88809a9fd000 0000000100000007 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809a9fd980: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff88809a9fda00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88809a9fda80: 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                      ^
 ffff88809a9fdb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88809a9fdb80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
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