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BUG: KASAN: slab-out-of-bounds in sctp_setsockopt_delayed_ack net/sctp/socket.c:2773 [inline]
BUG: KASAN: slab-out-of-bounds in sctp_setsockopt net/sctp/socket.c:4499 [inline]
BUG: KASAN: slab-out-of-bounds in sctp_setsockopt+0x91b5/0x95e0 net/sctp/socket.c:4431
Write of size 4 at addr ffff88809eb28188 by task syz-executor.0/32697

CPU: 1 PID: 32697 Comm: syz-executor.0 Not tainted 5.8.0-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+0x18f/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x436 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 sctp_setsockopt_delayed_ack net/sctp/socket.c:2773 [inline]
 sctp_setsockopt net/sctp/socket.c:4499 [inline]
 sctp_setsockopt+0x91b5/0x95e0 net/sctp/socket.c:4431
 __sys_setsockopt+0x337/0x6a0 net/socket.c:2137
 __do_sys_setsockopt net/socket.c:2153 [inline]
 __se_sys_setsockopt net/socket.c:2150 [inline]
 __x64_sys_setsockopt+0xba/0x150 net/socket.c:2150
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45c1f9
Code: Bad RIP value.
RSP: 002b:00007f98f8588c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 000000000002f3c0 RCX: 000000000045c1f9
RDX: 0000000000000010 RSI: 0000000000000084 RDI: 0000000000000008
RBP: 000000000078bf50 R08: 0000000000000008 R09: 0000000000000000
R10: 00000000200000c0 R11: 0000000000000246 R12: 000000000078bf0c
R13: 00007ffca6be43af R14: 00007f98f85899c0 R15: 000000000078bf0c

Allocated by task 32697:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:494
 __do_kmalloc mm/slab.c:3656 [inline]
 __kmalloc_track_caller+0x178/0x330 mm/slab.c:3671
 memdup_user+0x22/0xd0 mm/util.c:172
 sctp_setsockopt net/sctp/socket.c:4452 [inline]
 sctp_setsockopt+0x17a/0x95e0 net/sctp/socket.c:4431
 __sys_setsockopt+0x337/0x6a0 net/socket.c:2137
 __do_sys_setsockopt net/socket.c:2153 [inline]
 __se_sys_setsockopt net/socket.c:2150 [inline]
 __x64_sys_setsockopt+0xba/0x150 net/socket.c:2150
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 32328:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0xf5/0x140 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x103/0x2c0 mm/slab.c:3757
 kfree_const+0x51/0x60 mm/util.c:40
 kernfs_put.part.0+0x159/0x540 fs/kernfs/dir.c:528
 kernfs_put+0x42/0x50 fs/kernfs/dir.c:511
 sysfs_put include/linux/sysfs.h:611 [inline]
 kobject_del+0xfc/0x1f0 lib/kobject.c:631
 device_del+0x86a/0xd20 drivers/base/core.c:2869
 rollback_registered_many+0xa07/0xf60 net/core/dev.c:9013
 unregister_netdevice_many.part.0+0x1a/0x2f0 net/core/dev.c:10131
 unregister_netdevice_many+0x36/0x50 net/core/dev.c:10130
 rtnl_delete_link net/core/rtnetlink.c:2953 [inline]
 rtnl_dellink+0x351/0xa70 net/core/rtnetlink.c:3005
 rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5460
 netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2470
 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
 netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:671
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2363
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2417
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2450
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff88809eb28180
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 8 bytes inside of
 32-byte region [ffff88809eb28180, ffff88809eb281a0)
The buggy address belongs to the page:
page:ffffea00027aca00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88809eb28fc1
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00024db488 ffffea0002731d48 ffff8880aa0001c0
raw: ffff88809eb28fc1 ffff88809eb28000 0000000100000020 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809eb28080: 05 fc fc fc fc fc fc fc 05 fc fc fc fc fc fc fc
 ffff88809eb28100: 05 fc fc fc fc fc fc fc 05 fc fc fc fc fc fc fc
>ffff88809eb28180: 00 fc fc fc fc fc fc fc 07 fc fc fc fc fc fc fc
                      ^
 ffff88809eb28200: 07 fc fc fc fc fc fc fc 07 fc fc fc fc fc fc fc
 ffff88809eb28280: 04 fc fc fc fc fc fc fc fb fb fb fb fc fc fc fc
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