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BUG: KASAN: slab-use-after-free in __ethtool_get_link_ksettings+0x5e/0x170 net/ethtool/ioctl.c:443
Read of size 8 at addr ffff8880780e82f0 by task kworker/0:0/9

CPU: 0 UID: 0 PID: 9 Comm: kworker/0:0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Workqueue: events smc_ib_port_event_work
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 __ethtool_get_link_ksettings+0x5e/0x170 net/ethtool/ioctl.c:443
 ib_get_eth_speed+0x180/0x800 drivers/infiniband/core/verbs.c:2054
 rxe_query_port+0x93/0x3e0 drivers/infiniband/sw/rxe/rxe_verbs.c:62
 __ib_query_port drivers/infiniband/core/device.c:2153 [inline]
 ib_query_port+0x170/0x840 drivers/infiniband/core/device.c:2185
 smc_ib_remember_port_attr net/smc/smc_ib.c:364 [inline]
 smc_ib_port_event_work+0x15a/0x940 net/smc/smc_ib.c:388
 process_one_work+0x949/0x1650 kernel/workqueue.c:3279
 process_scheduled_works kernel/workqueue.c:3362 [inline]
 worker_thread+0xb46/0x1140 kernel/workqueue.c:3443
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 11184:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5174 [inline]
 __kvmalloc_node_noprof+0x528/0x8a0 mm/slub.c:6665
 alloc_netdev_mqs+0xa8/0x1200 net/core/dev.c:12028
 rtnl_create_link+0x31f/0xd70 net/core/rtnetlink.c:3648
 rtnl_newlink_create+0x277/0xb70 net/core/rtnetlink.c:3830
 __rtnl_newlink net/core/rtnetlink.c:3957 [inline]
 rtnl_newlink+0x1666/0x1be0 net/core/rtnetlink.c:4072
 rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6958
 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec+0x18f/0x1d0 net/socket.c:737
 __sock_sendmsg net/socket.c:752 [inline]
 __sys_sendto+0x3ff/0x590 net/socket.c:2221
 __do_sys_sendto net/socket.c:2228 [inline]
 __se_sys_sendto net/socket.c:2224 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2224
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 12:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2667 [inline]
 slab_free mm/slub.c:6079 [inline]
 kfree+0x1c1/0x630 mm/slub.c:6396
 device_release+0x9e/0x1d0 drivers/base/core.c:-1
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x228/0x560 lib/kobject.c:737
 netdev_run_todo+0xfaf/0x1130 net/core/dev.c:11729
 default_device_exit_batch+0x986/0xa00 net/core/dev.c:13073
 ops_exit_list net/core/net_namespace.c:205 [inline]
 ops_undo_list+0x52b/0x940 net/core/net_namespace.c:252
 cleanup_net+0x4df/0x7b0 net/core/net_namespace.c:696
 process_one_work+0x949/0x1650 kernel/workqueue.c:3279
 process_scheduled_works kernel/workqueue.c:3362 [inline]
 worker_thread+0xb46/0x1140 kernel/workqueue.c:3443
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 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 ffff8880780e8000
 which belongs to the cache kmalloc-cg-4k of size 4096
The buggy address is located 752 bytes inside of
 freed 4096-byte region [ffff8880780e8000, ffff8880780e9000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x780e8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff8880780e9011
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88813ff37500 dead000000000100 dead000000000122
raw: 0000000000000000 0000200000040004 00000000f5000000 ffff8880780e9011
head: 00fff00000000040 ffff88813ff37500 dead000000000100 dead000000000122
head: 0000000000000000 0000200000040004 00000000f5000000 ffff8880780e9011
head: 00fff00000000003 ffffea0001e03a01 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 5957, tgid 5957 (syz-executor), ts 188575693055, free_ts 159319112411
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1883
 prep_new_page mm/page_alloc.c:1891 [inline]
 get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3956
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5244
 alloc_slab_page mm/slub.c:3235 [inline]
 allocate_slab+0x7b/0x660 mm/slub.c:3408
 new_slab mm/slub.c:3466 [inline]
 refill_objects+0x331/0x3c0 mm/slub.c:7088
 refill_sheaf mm/slub.c:2784 [inline]
 __pcs_replace_empty_main+0x2b9/0x620 mm/slub.c:4533
 alloc_from_pcs mm/slub.c:4636 [inline]
 slab_alloc_node mm/slub.c:4770 [inline]
 __do_kmalloc_node mm/slub.c:5173 [inline]
 __kmalloc_noprof+0x474/0x760 mm/slub.c:5186
 kmalloc_noprof include/linux/slab.h:966 [inline]
 kzalloc_noprof include/linux/slab.h:1204 [inline]
 __register_sysctl_table+0x72/0x1340 fs/proc/proc_sysctl.c:1379
 __addrconf_sysctl_register+0x331/0x4d0 net/ipv6/addrconf.c:7328
 addrconf_sysctl_register+0x168/0x1c0 net/ipv6/addrconf.c:7376
 ipv6_add_dev+0xd44/0x13c0 net/ipv6/addrconf.c:460
 addrconf_notify+0x771/0x1050 net/ipv6/addrconf.c:3655
 notifier_call_chain+0x1be/0x400 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2281 [inline]
 call_netdevice_notifiers net/core/dev.c:2295 [inline]
 register_netdevice+0x173a/0x1cf0 net/core/dev.c:11447
 virt_wifi_newlink+0x428/0x860 drivers/net/wireless/virtual/virt_wifi.c:571
 rtnl_newlink_create+0x329/0xb70 net/core/rtnetlink.c:3840
page last free pid 5826 tgid 5826 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1432 [inline]
 __free_frozen_pages+0xc01/0xd80 mm/page_alloc.c:2972
 __folio_put+0x414/0x4f0 mm/swap.c:112
 pipe_buf_release include/linux/pipe_fs_i.h:273 [inline]
 pipe_update_tail fs/pipe.c:242 [inline]
 anon_pipe_read+0x660/0x10a0 fs/pipe.c:361
 new_sync_read fs/read_write.c:493 [inline]
 vfs_read+0x582/0xa70 fs/read_write.c:574
 ksys_read+0x150/0x270 fs/read_write.c:717
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff8880780e8180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880780e8200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880780e8280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                             ^
 ffff8880780e8300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880780e8380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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