================================================================== BUG: KASAN: use-after-free in tcp_probe_timer net/ipv4/tcp_timer.c:360 [inline] BUG: KASAN: use-after-free in tcp_write_timer_handler+0x8c6/0x8d0 net/ipv4/tcp_timer.c:596 Read of size 4 at addr ffff8880a539c750 by task kworker/u4:6/10774 CPU: 0 PID: 10774 Comm: kworker/u4:6 Not tainted 5.3.0-rc2+ #97 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+0x172/0x1f0 lib/dump_stack.c:113 print_address_description.cold+0xd4/0x306 mm/kasan/report.c:351 __kasan_report.cold+0x1b/0x36 mm/kasan/report.c:482 kasan_report+0x12/0x17 mm/kasan/common.c:612 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:131 tcp_probe_timer net/ipv4/tcp_timer.c:360 [inline] tcp_write_timer_handler+0x8c6/0x8d0 net/ipv4/tcp_timer.c:596 tcp_write_timer+0xa8/0x1e0 net/ipv4/tcp_timer.c:612 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1322 expire_timers kernel/time/timer.c:1366 [inline] __run_timers kernel/time/timer.c:1685 [inline] __run_timers kernel/time/timer.c:1653 [inline] run_timer_softirq+0x697/0x17a0 kernel/time/timer.c:1698 __do_softirq+0x262/0x98c kernel/softirq.c:292 do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1080 do_softirq.part.0+0x11a/0x170 kernel/softirq.c:337 do_softirq kernel/softirq.c:329 [inline] __local_bh_enable_ip+0x211/0x270 kernel/softirq.c:189 local_bh_enable include/linux/bottom_half.h:32 [inline] get_next_corpse net/netfilter/nf_conntrack_core.c:2014 [inline] nf_ct_iterate_cleanup+0x217/0x4e0 net/netfilter/nf_conntrack_core.c:2037 nf_ct_iterate_cleanup_net net/netfilter/nf_conntrack_core.c:2122 [inline] nf_ct_iterate_cleanup_net+0x133/0x190 net/netfilter/nf_conntrack_core.c:2107 masq_device_event+0xb5/0xe0 net/netfilter/nf_nat_masquerade.c:88 notifier_call_chain+0xc2/0x230 kernel/notifier.c:95 __raw_notifier_call_chain kernel/notifier.c:396 [inline] raw_notifier_call_chain+0x2e/0x40 kernel/notifier.c:403 call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1749 call_netdevice_notifiers_extack net/core/dev.c:1761 [inline] call_netdevice_notifiers net/core/dev.c:1775 [inline] dev_close_many+0x33f/0x6f0 net/core/dev.c:1518 rollback_registered_many+0x33f/0xdd0 net/core/dev.c:8173 unregister_netdevice_many.part.0+0x1b/0x1f0 net/core/dev.c:9304 unregister_netdevice_many net/core/dev.c:9303 [inline] default_device_exit_batch+0x34e/0x410 net/core/dev.c:9773 ops_exit_list.isra.0+0xfc/0x150 net/core/net_namespace.c:175 cleanup_net+0x4e2/0xa70 net/core/net_namespace.c:594 process_one_work+0x9af/0x1740 kernel/workqueue.c:2269 worker_thread+0x98/0xe40 kernel/workqueue.c:2415 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Allocated by task 28577: save_stack+0x23/0x90 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] __kasan_kmalloc mm/kasan/common.c:487 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:460 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:495 slab_post_alloc_hook mm/slab.h:520 [inline] slab_alloc mm/slab.c:3319 [inline] kmem_cache_alloc+0x121/0x710 mm/slab.c:3483 kmem_cache_zalloc include/linux/slab.h:738 [inline] net_alloc net/core/net_namespace.c:410 [inline] copy_net_ns+0xf1/0x41f net/core/net_namespace.c:462 create_new_namespaces+0x400/0x7b0 kernel/nsproxy.c:103 unshare_nsproxy_namespaces+0xc2/0x200 kernel/nsproxy.c:202 ksys_unshare+0x444/0x980 kernel/fork.c:2831 __do_sys_unshare kernel/fork.c:2899 [inline] __se_sys_unshare kernel/fork.c:2897 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:2897 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 10774: save_stack+0x23/0x90 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:449 kasan_slab_free+0xe/0x10 mm/kasan/common.c:457 __cache_free mm/slab.c:3425 [inline] kmem_cache_free+0x86/0x320 mm/slab.c:3693 net_free net/core/net_namespace.c:438 [inline] net_drop_ns.part.0+0x70/0x90 net/core/net_namespace.c:445 net_drop_ns net/core/net_namespace.c:444 [inline] cleanup_net+0x77a/0xa70 net/core/net_namespace.c:613 process_one_work+0x9af/0x1740 kernel/workqueue.c:2269 worker_thread+0x98/0xe40 kernel/workqueue.c:2415 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 The buggy address belongs to the object at ffff8880a539c180 which belongs to the cache net_namespace of size 6784 The buggy address is located 1488 bytes inside of 6784-byte region [ffff8880a539c180, ffff8880a539dc00) The buggy address belongs to the page: page:ffffea000294e700 refcount:1 mapcount:0 mapping:ffff8880a99a1e00 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea0001b0f488 ffffea0001eac108 ffff8880a99a1e00 raw: 0000000000000000 ffff8880a539c180 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a539c600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a539c680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880a539c700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a539c780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a539c800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================