syzbot

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BUG: KASAN: slab-use-after-free in __ethtool_get_link_ksettings+0x6e/0x190 net/ethtool/ioctl.c:443
Read of size 8 at addr ffff8880327d02e8 by task kworker/1:5/6088

CPU: 1 UID: 0 PID: 6088 Comm: kworker/1:5 Not tainted 6.16.0-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: events smc_ib_port_event_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 __ethtool_get_link_ksettings+0x6e/0x190 net/ethtool/ioctl.c:443
 ib_get_eth_speed+0x15e/0x7b0 drivers/infiniband/core/verbs.c:1996
 rxe_query_port+0x93/0x3b0 drivers/infiniband/sw/rxe/rxe_verbs.c:62
 __ib_query_port drivers/infiniband/core/device.c:2111 [inline]
 ib_query_port+0x16d/0x830 drivers/infiniband/core/device.c:2143
 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 kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 6377:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4328 [inline]
 __kvmalloc_node_noprof+0x30d/0x5f0 mm/slub.c:5015
 alloc_netdev_mqs+0xa6/0x11e0 net/core/dev.c:11711
 rtnl_create_link+0x31f/0xd10 net/core/rtnetlink.c:3631
 rtnl_newlink_create+0x25c/0xb00 net/core/rtnetlink.c:3813
 __rtnl_newlink net/core/rtnetlink.c:3940 [inline]
 rtnl_newlink+0x16d6/0x1c70 net/core/rtnetlink.c:4055
 rtnetlink_rcv_msg+0x7cc/0xb70 net/core/rtnetlink.c:6944
 netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2552
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x75c/0x8e0 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:727
 __sys_sendto+0x3bd/0x520 net/socket.c:2180
 __do_sys_sendto net/socket.c:2187 [inline]
 __se_sys_sendto net/socket.c:2183 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2183
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 49:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kfree+0x18e/0x440 mm/slub.c:4842
 device_release+0x9c/0x1c0 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+0x22b/0x480 lib/kobject.c:737
 netdev_run_todo+0xd2e/0xea0 net/core/dev.c:11412
 default_device_exit_batch+0x81e/0x890 net/core/dev.c:12645
 ops_exit_list net/core/net_namespace.c:206 [inline]
 ops_undo_list+0x522/0x990 net/core/net_namespace.c:253
 cleanup_net+0x4c5/0x800 net/core/net_namespace.c:686
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff8880327d0000
 which belongs to the cache kmalloc-cg-4k of size 4096
The buggy address is located 744 bytes inside of
 freed 4096-byte region [ffff8880327d0000, ffff8880327d1000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x327d0
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff88803448b641
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801a44b500 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000040004 00000000f5000000 ffff88803448b641
head: 00fff00000000040 ffff88801a44b500 dead000000000100 dead000000000122
head: 0000000000000000 0000000000040004 00000000f5000000 ffff88803448b641
head: 00fff00000000003 ffffea0000c9f401 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 0xd60c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_RETRY_MAYFAIL|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5954, tgid 5954 (syz-executor), ts 96983514666, free_ts 96381138886
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x21d5/0x22b0 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4959
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419
 alloc_slab_page mm/slub.c:2451 [inline]
 allocate_slab+0x8a/0x3b0 mm/slub.c:2619
 new_slab mm/slub.c:2673 [inline]
 ___slab_alloc+0xbfc/0x1480 mm/slub.c:3859
 __slab_alloc mm/slub.c:3949 [inline]
 __slab_alloc_node mm/slub.c:4024 [inline]
 slab_alloc_node mm/slub.c:4185 [inline]
 __do_kmalloc_node mm/slub.c:4327 [inline]
 __kvmalloc_node_noprof+0x429/0x5f0 mm/slub.c:5015
 kvmalloc_array_node_noprof include/linux/slab.h:1065 [inline]
 veth_alloc_queues drivers/net/veth.c:1432 [inline]
 veth_dev_init+0x363/0x570 drivers/net/veth.c:1455
 register_netdevice+0x6bf/0x1ae0 net/core/dev.c:11032
 veth_newlink+0x42f/0xa50 drivers/net/veth.c:1855
 rtnl_newlink_create+0x30d/0xb00 net/core/rtnetlink.c:3823
 __rtnl_newlink net/core/rtnetlink.c:3940 [inline]
 rtnl_newlink+0x16d6/0x1c70 net/core/rtnetlink.c:4055
 rtnetlink_rcv_msg+0x7cc/0xb70 net/core/rtnetlink.c:6944
 netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2552
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x75c/0x8e0 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
page last free pid 3441 tgid 3441 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1248 [inline]
 __free_frozen_pages+0xc65/0xe60 mm/page_alloc.c:2706
 __slab_free+0x326/0x400 mm/slub.c:4554
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4148 [inline]
 slab_alloc_node mm/slub.c:4197 [inline]
 kmem_cache_alloc_node_noprof+0x1bb/0x3c0 mm/slub.c:4249
 __alloc_skb+0x112/0x2d0 net/core/skbuff.c:660
 alloc_skb include/linux/skbuff.h:1336 [inline]
 nlmsg_new include/net/netlink.h:1041 [inline]
 rtmsg_fib+0xea/0x4c0 net/ipv4/fib_semantics.c:552
 fib_table_delete+0xca9/0xf80 net/ipv4/fib_trie.c:1740
 fib_magic+0x2e4/0x390 net/ipv4/fib_frontend.c:1135
 fib_del_ifaddr+0x1082/0x1480 net/ipv4/fib_frontend.c:1346
 fib_inetaddr_event+0xbb/0x190 net/ipv4/fib_frontend.c:1477
 notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85
 blocking_notifier_call_chain+0x6a/0x90 kernel/notifier.c:380
 __inet_del_ifa+0x87d/0x1040 net/ipv4/devinet.c:451
 inet_del_ifa net/ipv4/devinet.c:488 [inline]
 inetdev_destroy net/ipv4/devinet.c:328 [inline]
 inetdev_event+0x632/0x15b0 net/ipv4/devinet.c:1656

Memory state around the buggy address:
 ffff8880327d0180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880327d0200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880327d0280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                          ^
 ffff8880327d0300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880327d0380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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