================================================================== BUG: KASAN: slab-use-after-free in macvlan_forward_source+0x512/0x630 drivers/net/macvlan.c:436 Read of size 2 at addr ffff888029fb8dfc by task syz.1.2073/14062 CPU: 0 UID: 0 PID: 14062 Comm: syz.1.2073 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: 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 macvlan_forward_source+0x512/0x630 drivers/net/macvlan.c:436 macvlan_handle_frame+0x1ba/0x12e0 drivers/net/macvlan.c:495 __netif_receive_skb_core+0x95f/0x2f90 net/core/dev.c:6024 __netif_receive_skb_one_core net/core/dev.c:6135 [inline] __netif_receive_skb+0x72/0x380 net/core/dev.c:6250 netif_receive_skb_internal net/core/dev.c:6336 [inline] netif_receive_skb+0x1bb/0x750 net/core/dev.c:6395 tun_rx_batched+0x1b9/0x730 drivers/net/tun.c:1485 tun_get_user+0x2aa3/0x3dc0 drivers/net/tun.c:1953 tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:1999 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5c9/0xb30 fs/read_write.c:686 ksys_write+0x145/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f90edf8e1ff Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48 RSP: 002b:00007f90eedb6000 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f90ee1e6180 RCX: 00007f90edf8e1ff RDX: 000000000000004e RSI: 0000200000000180 RDI: 00000000000000c8 RBP: 00007f90ee013f91 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000004e R11: 0000000000000293 R12: 0000000000000000 R13: 00007f90ee1e6218 R14: 00007f90ee1e6180 R15: 00007ffd5dc50558 Allocated by task 13998: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:397 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414 kasan_kmalloc include/linux/kasan.h:262 [inline] __do_kmalloc_node mm/slub.c:5657 [inline] __kvmalloc_node_noprof+0x5d5/0x920 mm/slub.c:7134 alloc_netdev_mqs+0xa6/0x11b0 net/core/dev.c:11997 vti6_init_net+0x104/0x370 net/ipv6/ip6_vti.c:1146 ops_init+0x35c/0x5c0 net/core/net_namespace.c:137 setup_net+0x110/0x330 net/core/net_namespace.c:446 copy_net_ns+0x3e3/0x570 net/core/net_namespace.c:581 create_new_namespaces+0x3e7/0x6a0 kernel/nsproxy.c:130 unshare_nsproxy_namespaces+0x11c/0x170 kernel/nsproxy.c:226 ksys_unshare+0x4c8/0x8c0 kernel/fork.c:3171 __do_sys_unshare kernel/fork.c:3242 [inline] __se_sys_unshare kernel/fork.c:3240 [inline] __x64_sys_unshare+0x38/0x50 kernel/fork.c:3240 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 13998: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6668 [inline] kfree+0x1c0/0x660 mm/slub.c:6876 vti6_init_net+0x2e2/0x370 net/ipv6/ip6_vti.c:1168 ops_init+0x35c/0x5c0 net/core/net_namespace.c:137 setup_net+0x110/0x330 net/core/net_namespace.c:446 copy_net_ns+0x3e3/0x570 net/core/net_namespace.c:581 create_new_namespaces+0x3e7/0x6a0 kernel/nsproxy.c:130 unshare_nsproxy_namespaces+0x11c/0x170 kernel/nsproxy.c:226 ksys_unshare+0x4c8/0x8c0 kernel/fork.c:3171 __do_sys_unshare kernel/fork.c:3242 [inline] __se_sys_unshare kernel/fork.c:3240 [inline] __x64_sys_unshare+0x38/0x50 kernel/fork.c:3240 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888029fb8000 which belongs to the cache kmalloc-cg-4k of size 4096 The buggy address is located 3580 bytes inside of freed 4096-byte region [ffff888029fb8000, ffff888029fb9000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x29fb8 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 memcg:ffff88803317c501 anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88813ffb0500 0000000000000000 dead000000000001 raw: 0000000000000000 0000000000040004 00000000f5000000 ffff88803317c501 head: 00fff00000000040 ffff88813ffb0500 0000000000000000 dead000000000001 head: 0000000000000000 0000000000040004 00000000f5000000 ffff88803317c501 head: 00fff00000000003 ffffea0000a7ee01 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 11169, tgid 11169 (modprobe), ts 207829820236, free_ts 207789169305 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x234/0x290 mm/page_alloc.c:1846 prep_new_page mm/page_alloc.c:1854 [inline] get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3915 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486 alloc_slab_page mm/slub.c:3075 [inline] allocate_slab+0x86/0x3b0 mm/slub.c:3248 new_slab mm/slub.c:3302 [inline] ___slab_alloc+0xf2b/0x1960 mm/slub.c:4656 __slab_alloc+0x65/0x100 mm/slub.c:4779 __slab_alloc_node mm/slub.c:4855 [inline] slab_alloc_node mm/slub.c:5251 [inline] __do_kmalloc_node mm/slub.c:5656 [inline] __kvmalloc_node_noprof+0x6b6/0x920 mm/slub.c:7134 seq_buf_alloc fs/seq_file.c:38 [inline] seq_read_iter+0x202/0xe20 fs/seq_file.c:210 proc_reg_read_iter+0x1b7/0x280 fs/proc/inode.c:299 new_sync_read fs/read_write.c:491 [inline] vfs_read+0x55a/0xa30 fs/read_write.c:572 ksys_read+0x145/0x250 fs/read_write.c:715 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 11127 tgid 11119 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] __free_frozen_pages+0xbc8/0xd30 mm/page_alloc.c:2943 __folio_put+0x21b/0x2c0 mm/swap.c:112 folio_put include/linux/mm.h:1612 [inline] put_page include/linux/mm.h:1681 [inline] do_exit+0x183b/0x2310 kernel/exit.c:1002 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112 get_signal+0x1285/0x1340 kernel/signal.c:3034 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop+0x87/0x4f0 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2d0/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888029fb8c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888029fb8d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888029fb8d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888029fb8e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888029fb8e80: fb fb 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