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BUG: KASAN: slab-use-after-free in __ethtool_get_link_ksettings+0x1bf/0x200 net/ethtool/ioctl.c:443
Read of size 8 at addr ffff88806d1fc2e8 by task kworker/2:0/24

CPU: 2 UID: 0 PID: 24 Comm: kworker/2:0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: events smc_ib_port_event_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xcd/0x630 mm/kasan/report.c:482
 kasan_report+0xe0/0x110 mm/kasan/report.c:595
 __ethtool_get_link_ksettings+0x1bf/0x200 net/ethtool/ioctl.c:443
 __ethtool_get_link_ksettings+0x148/0x200 net/ethtool/ioctl.c:450
 ib_get_eth_speed+0x122/0xb50 drivers/infiniband/core/verbs.c:1996
 rxe_query_port+0x108/0x330 drivers/infiniband/sw/rxe/rxe_verbs.c:62
 __ib_query_port drivers/infiniband/core/device.c:2148 [inline]
 ib_query_port drivers/infiniband/core/device.c:2180 [inline]
 ib_query_port+0x441/0x8a0 drivers/infiniband/core/device.c:2170
 smc_ib_remember_port_attr net/smc/smc_ib.c:364 [inline]
 smc_ib_port_event_work+0x12f/0xbf0 net/smc/smc_ib.c:388
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
 process_scheduled_works kernel/workqueue.c:3346 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 5952:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 poison_kmalloc_redzone mm/kasan/common.c:400 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:417
 kasan_kmalloc include/linux/kasan.h:262 [inline]
 __do_kmalloc_node mm/slub.c:5642 [inline]
 __kvmalloc_node_noprof+0x3a3/0x9c0 mm/slub.c:7100
 alloc_netdev_mqs+0xd7/0x1550 net/core/dev.c:11900
 rtnl_create_link+0xc08/0xf90 net/core/rtnetlink.c:3641
 rtnl_newlink_create net/core/rtnetlink.c:3823 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3950 [inline]
 rtnl_newlink+0xb69/0x2000 net/core/rtnetlink.c:4065
 rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:6951
 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2552
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg net/socket.c:742 [inline]
 __sys_sendto+0x4a3/0x520 net/socket.c:2244
 __do_compat_sys_socketcall net/compat.c:475 [inline]
 __se_compat_sys_socketcall net/compat.c:423 [inline]
 __ia32_compat_sys_socketcall+0x625/0x770 net/compat.c:423
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0x7c/0x300 arch/x86/entry/syscall_32.c:306
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Freed by task 90:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 __kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:587
 kasan_save_free_info mm/kasan/kasan.h:406 [inline]
 poison_slab_object mm/kasan/common.c:252 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2539 [inline]
 slab_free mm/slub.c:6630 [inline]
 kfree+0x2b8/0x6d0 mm/slub.c:6837
 device_release+0xa4/0x240 drivers/base/core.c:2565
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1e7/0x5a0 lib/kobject.c:737
 netdev_run_todo+0x7e9/0x1320 net/core/dev.c:11601
 default_device_exit_batch+0x858/0xaf0 net/core/dev.c:12852
 ops_exit_list net/core/net_namespace.c:205 [inline]
 ops_undo_list+0x363/0xab0 net/core/net_namespace.c:252
 cleanup_net+0x41b/0x8b0 net/core/net_namespace.c:695
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
 process_scheduled_works kernel/workqueue.c:3346 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff88806d1fc000
 which belongs to the cache kmalloc-cg-4k of size 4096
The buggy address is located 744 bytes inside of
 freed 4096-byte region [ffff88806d1fc000, ffff88806d1fd000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x6d1f8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000040 ffff88801b44c280 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000
head: 04fff00000000040 ffff88801b44c280 dead000000000122 0000000000000000
head: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000
head: 04fff00000000003 ffffea0001b47e01 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 5952, tgid 5952 (syz-executor), ts 49140560517, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1850
 prep_new_page mm/page_alloc.c:1858 [inline]
 get_page_from_freelist+0x10a3/0x3a30 mm/page_alloc.c:3884
 __alloc_frozen_pages_noprof+0x25f/0x2470 mm/page_alloc.c:5183
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:3055 [inline]
 allocate_slab mm/slub.c:3228 [inline]
 new_slab+0x24a/0x360 mm/slub.c:3282
 ___slab_alloc+0xdae/0x1a60 mm/slub.c:4651
 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4770
 __slab_alloc_node mm/slub.c:4846 [inline]
 slab_alloc_node mm/slub.c:5268 [inline]
 __do_kmalloc_node mm/slub.c:5641 [inline]
 __kmalloc_node_track_caller_noprof+0x4db/0x8a0 mm/slub.c:5751
 kmemdup_noprof+0x29/0x60 mm/util.c:138
 kmemdup_noprof include/linux/fortify-string.h:765 [inline]
 __addrconf_sysctl_register+0xbb/0x360 net/ipv6/addrconf.c:7305
 addrconf_sysctl_register net/ipv6/addrconf.c:7371 [inline]
 addrconf_sysctl_register+0x15f/0x1f0 net/ipv6/addrconf.c:7360
 ipv6_add_dev+0xb31/0x15f0 net/ipv6/addrconf.c:460
 addrconf_notify+0x53e/0x19e0 net/ipv6/addrconf.c:3650
 notifier_call_chain+0xbc/0x410 kernel/notifier.c:85
 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2229
 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline]
 call_netdevice_notifiers net/core/dev.c:2281 [inline]
 register_netdevice+0x182e/0x2270 net/core/dev.c:11332
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88806d1fc180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88806d1fc200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88806d1fc280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                          ^
 ffff88806d1fc300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88806d1fc380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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