overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. overlayfs: filesystem on './file0' not supported as upperdir ================================================================== BUG: KASAN: use-after-free in tcp_retransmit_timer+0x2bd3/0x2f90 net/ipv4/tcp_timer.c:485 Read of size 8 at addr ffff888094eecbb8 by task kworker/u4:1/9117 CPU: 0 PID: 9117 Comm: kworker/u4:1 Not tainted 4.19.91-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report mm/kasan/report.c:412 [inline] kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:396 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 tcp_retransmit_timer+0x2bd3/0x2f90 net/ipv4/tcp_timer.c:485 tcp_write_timer_handler+0x513/0x900 net/ipv4/tcp_timer.c:598 tcp_write_timer+0x111/0x1d0 net/ipv4/tcp_timer.c:618 call_timer_fn+0x18d/0x720 kernel/time/timer.c:1326 expire_timers kernel/time/timer.c:1363 [inline] __run_timers kernel/time/timer.c:1684 [inline] __run_timers kernel/time/timer.c:1652 [inline] run_timer_softirq+0x64f/0x16a0 kernel/time/timer.c:1697 __do_softirq+0x25c/0x921 kernel/softirq.c:292 invoke_softirq kernel/softirq.c:372 [inline] irq_exit+0x180/0x1d0 kernel/softirq.c:412 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x13b/0x550 arch/x86/kernel/apic/apic.c:1094 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893 RIP: 0010:should_resched arch/x86/include/asm/preempt.h:99 [inline] RIP: 0010:__local_bh_enable_ip+0x18e/0x270 kernel/softirq.c:196 Code: 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85 df 00 00 00 48 83 3d 57 f8 b1 07 00 0f 84 8f 00 00 00 fb 66 0f 1f 44 00 00 <65> 8b 05 3b 8a c1 7e 85 c0 74 7f 5b 41 5c 41 5d 5d c3 80 3d 3c 22 RSP: 0018:ffff8880841df6c0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff11e4b7b RBX: 0000000000000200 RCX: 1ffff1101214c1b3 RDX: dffffc0000000000 RSI: ffff888090a60d78 RDI: ffff888090a60cfc RBP: ffff8880841df6d8 R08: ffff888090a60480 R09: ffff888090a60d98 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff85ee28e1 R13: ffff888090a60480 R14: 0000000000000001 R15: dffffc0000000000 local_bh_enable include/linux/bottom_half.h:32 [inline] get_next_corpse net/netfilter/nf_conntrack_core.c:1928 [inline] nf_ct_iterate_cleanup+0x217/0x4e0 net/netfilter/nf_conntrack_core.c:1951 nf_ct_iterate_cleanup_net net/netfilter/nf_conntrack_core.c:2036 [inline] nf_ct_iterate_cleanup_net+0x133/0x190 net/netfilter/nf_conntrack_core.c:2021 masq_device_event+0xb5/0xe0 net/ipv6/netfilter/nf_nat_masquerade_ipv6.c:77 notifier_call_chain+0xc2/0x230 kernel/notifier.c:93 __raw_notifier_call_chain kernel/notifier.c:394 [inline] raw_notifier_call_chain+0x2e/0x40 kernel/notifier.c:401 call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1747 call_netdevice_notifiers net/core/dev.c:1765 [inline] dev_close_many+0x33f/0x6f0 net/core/dev.c:1517 rollback_registered_many+0x33f/0xda0 net/core/dev.c:7997 unregister_netdevice_many.part.0+0x1b/0x1f0 net/core/dev.c:9130 unregister_netdevice_many+0x3b/0x50 net/core/dev.c:9129 ip_tunnel_delete_nets+0x41e/0x5f0 net/ipv4/ip_tunnel.c:1079 ipgre_tap_exit_batch_net+0x23/0x30 net/ipv4/ip_gre.c:1661 ops_exit_list.isra.0+0xfc/0x150 net/core/net_namespace.c:156 cleanup_net+0x404/0x960 net/core/net_namespace.c:553 process_one_work+0x989/0x1750 kernel/workqueue.c:2153 worker_thread+0x98/0xe40 kernel/workqueue.c:2296 kthread+0x354/0x420 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Allocated by task 28074: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc mm/kasan/kasan.c:553 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:531 kasan_slab_alloc+0xf/0x20 mm/kasan/kasan.c:490 kmem_cache_alloc+0x12e/0x700 mm/slab.c:3559 kmem_cache_zalloc include/linux/slab.h:699 [inline] net_alloc net/core/net_namespace.c:385 [inline] copy_net_ns+0xed/0x33c net/core/net_namespace.c:425 create_new_namespaces+0x400/0x7b0 kernel/nsproxy.c:107 unshare_nsproxy_namespaces+0xc2/0x200 kernel/nsproxy.c:206 ksys_unshare+0x440/0x980 kernel/fork.c:2520 __do_sys_unshare kernel/fork.c:2588 [inline] __se_sys_unshare kernel/fork.c:2586 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:2586 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 9117: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3503 [inline] kmem_cache_free+0x86/0x260 mm/slab.c:3765 net_free net/core/net_namespace.c:401 [inline] net_drop_ns+0x7e/0x90 net/core/net_namespace.c:408 cleanup_net+0x53b/0x960 net/core/net_namespace.c:571 process_one_work+0x989/0x1750 kernel/workqueue.c:2153 worker_thread+0x98/0xe40 kernel/workqueue.c:2296 kthread+0x354/0x420 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 The buggy address belongs to the object at ffff888094eec980 which belongs to the cache net_namespace of size 8640 The buggy address is located 568 bytes inside of 8640-byte region [ffff888094eec980, ffff888094eeeb40) The buggy address belongs to the page: page:ffffea000253bb00 count:1 mapcount:0 mapping:ffff88821bab2540 index:0x0 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffffea0002720d08 ffffea0000be0608 ffff88821bab2540 raw: 0000000000000000 ffff888094eec980 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888094eeca80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888094eecb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888094eecb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb kobject: 'loop2' (0000000004da3b6e): fill_kobj_path: path = '/devices/virtual/block/loop2' ^ ffff888094eecc00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888094eecc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================