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BUG: KASAN: use-after-free in macsec_get_iflink+0x6d/0x70 drivers/net/macsec.c:3682
Read of size 4 at addr ffff88800a448100 by task kworker/u4:1/9

CPU: 1 PID: 9 Comm: kworker/u4:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2025
Workqueue: events_unbound linkwatch_event
Call Trace:
 __dump_stack+0x21/0x24 lib/dump_stack.c:77
 dump_stack_lvl+0x169/0x1d8 lib/dump_stack.c:118
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:435 [inline]
 kasan_report+0xe2/0x130 mm/kasan/report.c:452
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
 macsec_get_iflink+0x6d/0x70 drivers/net/macsec.c:3682
 dev_get_iflink+0x70/0xc0 net/core/dev.c:824
 default_operstate net/core/link_watch.c:41 [inline]
 rfc2863_policy+0x124/0x2b0 net/core/link_watch.c:53
 linkwatch_do_dev+0x3b/0x140 net/core/link_watch.c:160
 __linkwatch_run_queue+0x4a9/0x7b0 net/core/link_watch.c:213
 linkwatch_event+0x4c/0x60 net/core/link_watch.c:252
 process_one_work+0x6e1/0xba0 kernel/workqueue.c:2301
 worker_thread+0xa6a/0x13b0 kernel/workqueue.c:2447
 kthread+0x346/0x3d0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

Allocated by task 30129:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:430 [inline]
 ____kasan_kmalloc mm/kasan/common.c:509 [inline]
 __kasan_kmalloc+0xda/0x110 mm/kasan/common.c:518
 kasan_kmalloc include/linux/kasan.h:254 [inline]
 __kmalloc+0x1a7/0x330 mm/slub.c:4038
 __kmalloc_node include/linux/slab.h:418 [inline]
 kmalloc_node include/linux/slab.h:575 [inline]
 kvmalloc_node+0x88/0x130 mm/util.c:612
 kvmalloc include/linux/mm.h:833 [inline]
 kvzalloc include/linux/mm.h:841 [inline]
 alloc_netdev_mqs+0x88/0xc80 net/core/dev.c:10527
 rtnl_create_link+0x242/0x930 net/core/rtnetlink.c:3195
 veth_newlink+0x278/0xbb0 drivers/net/veth.c:1344
 __rtnl_newlink net/core/rtnetlink.c:3482 [inline]
 rtnl_newlink+0x11bd/0x1640 net/core/rtnetlink.c:3530
 rtnetlink_rcv_msg+0x9db/0xb90 net/core/rtnetlink.c:5610
 netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2503
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5628
 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
 netlink_unicast+0x876/0xa40 net/netlink/af_netlink.c:1340
 netlink_sendmsg+0x88d/0xb30 net/netlink/af_netlink.c:1914
 sock_sendmsg_nosec net/socket.c:652 [inline]
 __sock_sendmsg net/socket.c:664 [inline]
 __sys_sendto+0x41d/0x580 net/socket.c:2006
 __do_sys_sendto net/socket.c:2018 [inline]
 __se_sys_sendto net/socket.c:2014 [inline]
 __x64_sys_sendto+0xe5/0x100 net/socket.c:2014
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

Freed by task 314:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4a/0x70 mm/kasan/common.c:45
 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370
 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:362
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:370
 kasan_slab_free include/linux/kasan.h:220 [inline]
 slab_free_hook mm/slub.c:1600 [inline]
 slab_free_freelist_hook+0xc5/0x190 mm/slub.c:1626
 slab_free mm/slub.c:3208 [inline]
 kfree+0xc0/0x270 mm/slub.c:4196
 kvfree+0x35/0x40 mm/util.c:647
 netdev_freemem+0x3f/0x60 net/core/dev.c:10481
 netdev_release+0x7f/0xb0 net/core/net-sysfs.c:1886
 device_release+0x96/0x1c0 drivers/base/core.c:-1
 kobject_cleanup lib/kobject.c:713 [inline]
 kobject_release lib/kobject.c:744 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x18a/0x270 lib/kobject.c:761
 netdev_run_todo+0xb99/0xd20 net/core/dev.c:10352
 rtnl_unlock+0xe/0x10 net/core/rtnetlink.c:112
 default_device_exit_batch+0x335/0x390 net/core/dev.c:11288
 ops_exit_list net/core/net_namespace.c:190 [inline]
 cleanup_net+0x5fb/0xb70 net/core/net_namespace.c:609
 process_one_work+0x6e1/0xba0 kernel/workqueue.c:2301
 worker_thread+0xa6a/0x13b0 kernel/workqueue.c:2447
 kthread+0x346/0x3d0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

The buggy address belongs to the object at ffff88800a448000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 256 bytes inside of
 4096-byte region [ffff88800a448000, ffff88800a449000)
The buggy address belongs to the page:
page:ffffea0000291200 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88800a44e000 pfn:0xa448
head:ffffea0000291200 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x10200(slab|head)
raw: 0000000000010200 ffffea0007572808 ffffea00001ee008 ffff888100042c00
raw: ffff88800a44e000 0000000000040002 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d2a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 30129, ts 368129290227, free_ts 368119936777
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2456 [inline]
 prep_new_page+0x179/0x180 mm/page_alloc.c:2462
 get_page_from_freelist+0x2235/0x23d0 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x268/0x5f0 mm/page_alloc.c:5370
 alloc_slab_page mm/slub.c:-1 [inline]
 allocate_slab mm/slub.c:1813 [inline]
 new_slab+0x84/0x3f0 mm/slub.c:1874
 new_slab_objects mm/slub.c:2632 [inline]
 ___slab_alloc+0x2a6/0x450 mm/slub.c:2796
 __slab_alloc+0x63/0xa0 mm/slub.c:2836
 slab_alloc_node mm/slub.c:2918 [inline]
 slab_alloc mm/slub.c:2960 [inline]
 __kmalloc_track_caller+0x1ef/0x320 mm/slub.c:4541
 __kmalloc_reserve net/core/skbuff.c:144 [inline]
 __alloc_skb+0xdc/0x520 net/core/skbuff.c:212
 alloc_skb include/linux/skbuff.h:1126 [inline]
 nlmsg_new include/net/netlink.h:953 [inline]
 rtmsg_ifinfo_build_skb+0x7c/0x180 net/core/rtnetlink.c:3844
 rtmsg_ifinfo_event net/core/rtnetlink.c:3880 [inline]
 rtmsg_ifinfo+0x7a/0x130 net/core/rtnetlink.c:3889
 __dev_notify_flags+0xdb/0x500 net/core/dev.c:8568
 rtnl_configure_link+0x22e/0x330 net/core/rtnetlink.c:-1
 __rtnl_newlink net/core/rtnetlink.c:3490 [inline]
 rtnl_newlink+0x12d1/0x1640 net/core/rtnetlink.c:3530
 rtnetlink_rcv_msg+0x9db/0xb90 net/core/rtnetlink.c:5610
 netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2503
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5628
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:28 [inline]
 free_pages_prepare mm/page_alloc.c:1349 [inline]
 __free_pages_ok+0x7fc/0x820 mm/page_alloc.c:1629
 free_the_page mm/page_alloc.c:5431 [inline]
 __free_pages+0xdd/0x380 mm/page_alloc.c:5440
 __free_slab+0xcf/0x190 mm/slub.c:1899
 free_slab mm/slub.c:1914 [inline]
 discard_slab mm/slub.c:1920 [inline]
 unfreeze_partials+0x15f/0x190 mm/slub.c:2415
 put_cpu_partial+0xc1/0x180 mm/slub.c:2451
 __slab_free+0x2c9/0x3a0 mm/slub.c:3100
 do_slab_free mm/slub.c:3196 [inline]
 ___cache_free+0x111/0x130 mm/slub.c:3215
 qlink_free+0x50/0x90 mm/kasan/quarantine.c:157
 qlist_free_all+0x5f/0xb0 mm/kasan/quarantine.c:176
 kasan_quarantine_reduce+0x14a/0x160 mm/kasan/quarantine.c:283
 __kasan_slab_alloc+0x2f/0xf0 mm/kasan/common.c:440
 kasan_slab_alloc include/linux/kasan.h:244 [inline]
 slab_post_alloc_hook+0x5d/0x2f0 mm/slab.h:580
 slab_alloc_node mm/slub.c:2952 [inline]
 slab_alloc mm/slub.c:2960 [inline]
 kmem_cache_alloc+0x165/0x2e0 mm/slub.c:2965
 kmem_cache_zalloc include/linux/slab.h:654 [inline]
 __kernfs_new_node+0xdb/0x680 fs/kernfs/dir.c:662
 kernfs_new_node+0x150/0x260 fs/kernfs/dir.c:739
 __kernfs_create_file+0x4e/0x270 fs/kernfs/file.c:987

Memory state around the buggy address:
 ffff88800a448000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88800a448080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88800a448100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff88800a448180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88800a448200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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