Hello, syzbot found the following issue on: HEAD commit: 26aed0ea Add linux-next specific files for 20201216 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=16c492cb500000 kernel config: https://syzkaller.appspot.com/x/.config?x=5c81cc44aa25b5b3 dashboard link: https://syzkaller.appspot.com/bug?extid=48313eb09ec08f5ea43a compiler: gcc (GCC) 10.1.0-syz 20200507 Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+48313eb09ec08f5ea43a@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KASAN: double-free or invalid-free in slab_free mm/slub.c:3157 [inline] BUG: KASAN: double-free or invalid-free in kfree+0xdb/0x3c0 mm/slub.c:4156 CPU: 0 PID: 4913 Comm: systemd-udevd Not tainted 5.10.0-next-20201216-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:120 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:230 kasan_report_invalid_free+0x51/0x80 mm/kasan/report.c:355 ____kasan_slab_free.part.0+0xfd/0x110 mm/kasan/common.c:345 kasan_slab_free include/linux/kasan.h:188 [inline] slab_free_hook mm/slub.c:1548 [inline] slab_free_freelist_hook+0x82/0x1d0 mm/slub.c:1586 slab_free mm/slub.c:3157 [inline] kfree+0xdb/0x3c0 mm/slub.c:4156 bdev_free_inode+0x57/0x80 fs/block_dev.c:788 i_callback+0x3f/0x70 fs/inode.c:222 rcu_do_batch kernel/rcu/tree.c:2489 [inline] rcu_core+0x75d/0xf80 kernel/rcu/tree.c:2723 __do_softirq+0x2bc/0xa77 kernel/softirq.c:343 asm_call_irq_on_stack+0xf/0x20 </IRQ> __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline] do_softirq_own_stack+0xaa/0xd0 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:226 [inline] __irq_exit_rcu+0x17f/0x200 kernel/softirq.c:420 irq_exit_rcu+0x5/0x20 kernel/softirq.c:432 sysvec_apic_timer_interrupt+0x4d/0x100 arch/x86/kernel/apic/apic.c:1096 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:628 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/irqflags.h:85 [inline] RIP: 0010:lock_acquire kernel/locking/lockdep.c:5440 [inline] RIP: 0010:lock_acquire+0x2c7/0x750 kernel/locking/lockdep.c:5402 Code: 48 c7 c7 c0 9f 6b 89 48 83 c4 20 e8 63 ac c1 07 b8 ff ff ff ff 65 0f c1 05 66 e3 a9 7e 83 f8 01 0f 85 40 03 00 00 ff 34 24 9d <e9> 3a fe ff ff 65 ff 05 cd d1 a9 7e 48 8b 05 c6 32 12 0c e8 81 a1 RSP: 0018:ffffc900015af8c0 EFLAGS: 00000246 RAX: 0000000000000001 RBX: 1ffff920002b5f1a RCX: 0000000000000001 RDX: 1ffff1100322c491 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff8f5157b7 R10: fffffbfff1ea2af6 R11: 0000000000000001 R12: 0000000000000000 R13: ffffffff8b8e89c0 R14: 0000000000000000 R15: 0000000000000000 fs_reclaim_acquire mm/page_alloc.c:4338 [inline] fs_reclaim_acquire+0xd2/0x150 mm/page_alloc.c:4329 might_alloc include/linux/sched/mm.h:193 [inline] slab_pre_alloc_hook mm/slab.h:499 [inline] slab_alloc_node mm/slub.c:2822 [inline] slab_alloc mm/slub.c:2911 [inline] kmem_cache_alloc+0x3e/0x380 mm/slub.c:2916 anon_vma_chain_alloc mm/rmap.c:136 [inline] anon_vma_fork+0x1df/0x630 mm/rmap.c:357 dup_mmap kernel/fork.c:551 [inline] dup_mm+0x9a6/0x1380 kernel/fork.c:1362 copy_mm kernel/fork.c:1418 [inline] copy_process+0x2a3e/0x6fe0 kernel/fork.c:2100 kernel_clone+0xe7/0xad0 kernel/fork.c:2465 __do_sys_clone+0xc8/0x110 kernel/fork.c:2582 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f645bff638b Code: db 45 85 f6 0f 85 95 01 00 00 64 4c 8b 04 25 10 00 00 00 31 d2 4d 8d 90 d0 02 00 00 31 f6 bf 11 00 20 01 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 de 00 00 00 85 c0 41 89 c5 0f 85 e5 00 00 RSP: 002b:00007ffe156cbc30 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffe156cbc30 RCX: 00007f645bff638b RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007ffe156cbc80 R08: 00007f645d1a68c0 R09: 0000000000000210 R10: 00007f645d1a6b90 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000020 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 760: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:39 kasan_set_track mm/kasan/common.c:47 [inline] set_alloc_info mm/kasan/common.c:405 [inline] ____kasan_kmalloc mm/kasan/common.c:436 [inline] ____kasan_kmalloc.constprop.0+0xa0/0xd0 mm/kasan/common.c:408 kasan_slab_alloc include/linux/kasan.h:205 [inline] slab_post_alloc_hook mm/slab.h:518 [inline] slab_alloc_node mm/slub.c:2903 [inline] slab_alloc mm/slub.c:2911 [inline] __kmalloc_track_caller+0x163/0x2e0 mm/slub.c:4496 kmemdup+0x23/0x50 mm/util.c:128 kmemdup include/linux/string.h:520 [inline] mpls_dev_sysctl_register+0xaa/0x2d0 net/mpls/af_mpls.c:1407 mpls_add_dev net/mpls/af_mpls.c:1473 [inline] mpls_dev_notify+0x281/0x970 net/mpls/af_mpls.c:1589 notifier_call_chain+0xb5/0x200 kernel/notifier.c:83 call_netdevice_notifiers_info+0xb5/0x150 net/core/dev.c:2022 call_netdevice_notifiers_extack net/core/dev.c:2034 [inline] call_netdevice_notifiers net/core/dev.c:2048 [inline] register_netdevice+0x1085/0x16a0 net/core/dev.c:10059 register_netdev+0x2d/0x50 net/core/dev.c:10159 loopback_net_init+0x73/0x160 drivers/net/loopback.c:216 ops_init+0xaf/0x490 net/core/net_namespace.c:152 setup_net+0x2de/0x850 net/core/net_namespace.c:342 copy_net_ns+0x376/0x7b0 net/core/net_namespace.c:483 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110 copy_namespaces+0x3e5/0x4a0 kernel/nsproxy.c:178 copy_process+0x2aa7/0x6fe0 kernel/fork.c:2103 kernel_clone+0xe7/0xad0 kernel/fork.c:2465 __do_sys_clone+0xc8/0x110 kernel/fork.c:2582 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 9: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:39 kasan_set_track+0x1c/0x30 mm/kasan/common.c:47 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:355 ____kasan_slab_free.part.0+0xe1/0x110 mm/kasan/common.c:366 kasan_slab_free include/linux/kasan.h:188 [inline] slab_free_hook mm/slub.c:1548 [inline] slab_free_freelist_hook+0x82/0x1d0 mm/slub.c:1586 slab_free mm/slub.c:3157 [inline] kfree+0xdb/0x3c0 mm/slub.c:4156 mpls_dev_sysctl_unregister net/mpls/af_mpls.c:1443 [inline] mpls_dev_notify+0x684/0x970 net/mpls/af_mpls.c:1622 notifier_call_chain+0xb5/0x200 kernel/notifier.c:83 call_netdevice_notifiers_info+0xb5/0x150 net/core/dev.c:2022 call_netdevice_notifiers_extack net/core/dev.c:2034 [inline] call_netdevice_notifiers net/core/dev.c:2048 [inline] rollback_registered_many+0x92e/0x1530 net/core/dev.c:9477 unregister_netdevice_many.part.0+0x1a/0x2f0 net/core/dev.c:10701 unregister_netdevice_many net/core/dev.c:10700 [inline] default_device_exit_batch+0x30c/0x3d0 net/core/dev.c:11184 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:190 cleanup_net+0x4ea/0xb10 net/core/net_namespace.c:604 process_one_work+0x98d/0x1630 kernel/workqueue.c:2275 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Last potentially related work creation: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:39 kasan_record_aux_stack+0xdc/0x100 mm/kasan/generic.c:343 __call_rcu kernel/rcu/tree.c:2965 [inline] call_rcu+0xbb/0x710 kernel/rcu/tree.c:3038 nf_hook_entries_free net/netfilter/core.c:88 [inline] nf_hook_entries_free net/netfilter/core.c:75 [inline] __nf_register_net_hook+0x2c7/0x630 net/netfilter/core.c:424 nf_register_net_hook+0x114/0x170 net/netfilter/core.c:541 nf_register_net_hooks+0x59/0xc0 net/netfilter/core.c:557 nf_nat_register_fn+0x38d/0x5a0 net/netfilter/nf_nat_core.c:1063 ipt_nat_register_lookups net/ipv4/netfilter/iptable_nat.c:68 [inline] iptable_nat_table_init.part.0+0x84/0x1e0 net/ipv4/netfilter/iptable_nat.c:106 iptable_nat_table_init+0x4f/0x70 net/ipv4/netfilter/iptable_nat.c:114 xt_find_table_lock+0x2d9/0x540 net/netfilter/x_tables.c:1223 xt_request_find_table_lock+0x27/0xf0 net/netfilter/x_tables.c:1253 get_info+0x16a/0x710 net/ipv6/netfilter/ip6_tables.c:980 do_ipt_get_ctl+0x152/0x9d0 net/ipv4/netfilter/ip_tables.c:1651 nf_getsockopt+0x72/0xd0 net/netfilter/nf_sockopt.c:116 ip_getsockopt net/ipv4/ip_sockglue.c:1777 [inline] ip_getsockopt+0x164/0x1c0 net/ipv4/ip_sockglue.c:1756 tcp_getsockopt+0x86/0xd0 net/ipv4/tcp.c:4141 __sys_getsockopt+0x219/0x4c0 net/socket.c:2156 __do_sys_getsockopt net/socket.c:2171 [inline] __se_sys_getsockopt net/socket.c:2168 [inline] __x64_sys_getsockopt+0xba/0x150 net/socket.c:2168 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Second to last potentially related work creation: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:39 kasan_record_aux_stack+0xdc/0x100 mm/kasan/generic.c:343 __call_rcu kernel/rcu/tree.c:2965 [inline] call_rcu+0xbb/0x710 kernel/rcu/tree.c:3038 inet_free_ifa net/ipv4/devinet.c:231 [inline] inetdev_destroy net/ipv4/devinet.c:319 [inline] inetdev_event+0x6f9/0x16c0 net/ipv4/devinet.c:1598 notifier_call_chain+0xb5/0x200 kernel/notifier.c:83 call_netdevice_notifiers_info+0xb5/0x150 net/core/dev.c:2022 call_netdevice_notifiers_extack net/core/dev.c:2034 [inline] call_netdevice_notifiers net/core/dev.c:2048 [inline] rollback_registered_many+0x92e/0x1530 net/core/dev.c:9477 unregister_netdevice_many.part.0+0x1a/0x2f0 net/core/dev.c:10701 unregister_netdevice_many net/core/dev.c:10700 [inline] default_device_exit_batch+0x30c/0x3d0 net/core/dev.c:11184 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:190 cleanup_net+0x4ea/0xb10 net/core/net_namespace.c:604 process_one_work+0x98d/0x1630 kernel/workqueue.c:2275 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 The buggy address belongs to the object at ffff888018fa2000 which belongs to the cache kmalloc-128 of size 128 The buggy address is located 0 bytes inside of 128-byte region [ffff888018fa2000, ffff888018fa2080) The buggy address belongs to the page: page:0000000085654d51 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x18fa2 flags: 0xfff00000000200(slab) raw: 00fff00000000200 dead000000000100 dead000000000122 ffff888010841640 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888018fa1f00: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc ffff888018fa1f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888018fa2000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888018fa2080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888018fa2100: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- This report is generated by a bot. 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