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BUG: KASAN: slab-use-after-free in __ethtool_get_link_ksettings+0x230/0x250
Read of size 1 at addr ffff88811080ae09 by task kworker/0:14/17042

CPU: 0 UID: 0 PID: 17042 Comm: kworker/0:14 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: events smc_ib_port_event_work
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 print_address_description+0x55/0x1e0
 print_report+0x58/0x70
 kasan_report+0x117/0x150
 __ethtool_get_link_ksettings+0x230/0x250
 __ethtool_get_link_ksettings+0x11f/0x250
 ib_get_eth_speed+0x180/0x7f0
 rxe_query_port+0x93/0x3d0
 ib_query_port+0x16e/0x830
 smc_ib_port_event_work+0x147/0x920
 process_scheduled_works+0xa88/0x14c0
 worker_thread+0xa47/0xfb0
 kthread+0x38b/0x480
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Allocated by task 5597:
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kvmalloc_node_noprof+0x543/0x870
 alloc_netdev_mqs+0xa9/0x12b0
 rtnl_create_link+0x321/0xd70
 rtnl_newlink_create+0x25f/0xb00
 rtnl_newlink+0x167f/0x1bd0
 rtnetlink_rcv_msg+0x802/0xc00
 netlink_rcv_skb+0x226/0x4a0
 netlink_unicast+0x7bd/0x940
 netlink_sendmsg+0x813/0xb40
 sock_sendmsg_nosec+0x13a/0x180
 __sys_sendto+0x408/0x5a0
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 16223:
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x40/0x50
 __kasan_slab_free+0x5c/0x80
 kfree+0x1c5/0x640
 device_release+0xc4/0x1f0
 kobject_put+0x222/0x550
 netdev_run_todo+0xf56/0x10d0
 default_device_exit_batch+0x966/0x9e0
 ops_undo_list+0x4b4/0x8d0
 cleanup_net+0x572/0x810
 process_scheduled_works+0xa88/0x14c0
 worker_thread+0xa47/0xfb0
 kthread+0x38b/0x480
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30

The buggy address belongs to the object at ffff88811080a000
 which belongs to the cache kmalloc-cg-4k of size 4096
The buggy address is located 3593 bytes inside of
 freed 4096-byte region [ffff88811080a000, ffff88811080b000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x110808
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888111c88001
flags: 0x17ff00000000040(head|node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 017ff00000000040 ffff88810004b500 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800040004 00000000f5000000 ffff888111c88001
head: 017ff00000000040 ffff88810004b500 dead000000000100 dead000000000122
head: 0000000000000000 0000000800040004 00000000f5000000 ffff888111c88001
head: 017ff00000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5597, tgid 5597 (syz-executor), ts 69120487245, free_ts 69105185608
 post_alloc_hook+0x1f9/0x250
 get_page_from_freelist+0x21fe/0x2270
 __alloc_frozen_pages_noprof+0x18d/0x380
 allocate_slab+0x79/0x5e0
 refill_objects+0x2d5/0x350
 __pcs_replace_empty_main+0x2c3/0x6b0
 __kmalloc_noprof+0x489/0x720
 __register_sysctl_table+0x6f/0x1370
 __addrconf_sysctl_register+0x31c/0x4b0
 addrconf_sysctl_register+0x168/0x1c0
 ipv6_add_dev+0xd26/0x13a0
 addrconf_notify+0x771/0x1050
 notifier_call_chain+0x1a5/0x3d0
 register_netdevice+0x18a4/0x1eb0
 virt_wifi_newlink+0x3be/0x7c0
 rtnl_newlink_create+0x310/0xb00
page last free pid 5597 tgid 5597 stack trace:
 __free_frozen_pages+0xc22/0xd20
 __slab_free+0x274/0x2c0
 qlist_free_all+0x99/0x100
 kasan_quarantine_reduce+0x148/0x160
 __kasan_slab_alloc+0x22/0x80
 __kmalloc_cache_noprof+0x2af/0x660
 ref_tracker_alloc+0x15b/0x4b0
 netdev_queue_update_kobjects+0x1d1/0x6b0
 netdev_register_kobject+0x277/0x350
 register_netdevice+0x1433/0x1eb0
 veth_newlink+0x676/0xb70
 rtnl_newlink_create+0x310/0xb00
 rtnl_newlink+0x167f/0x1bd0
 rtnetlink_rcv_msg+0x802/0xc00
 netlink_rcv_skb+0x226/0x4a0
 netlink_unicast+0x7bd/0x940

Memory state around the buggy address:
 ffff88811080ad00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88811080ad80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811080ae00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff88811080ae80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88811080af00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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