================================================================== BUG: KASAN: use-after-free in inet_frag_destroy_rcu+0xd9/0xe0 net/ipv4/inet_fragment.c:201 Read of size 8 at addr ffff8880969c4d18 by task kworker/u4:3/686 CPU: 0 PID: 686 Comm: kworker/u4:3 Not tainted 5.2.0-rc1+ #2 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+0x7c/0x20d mm/kasan/report.c:188 __kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 kasan_report+0x12/0x20 mm/kasan/common.c:614 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132 inet_frag_destroy_rcu+0xd9/0xe0 net/ipv4/inet_fragment.c:201 __rcu_reclaim kernel/rcu/rcu.h:222 [inline] rcu_do_batch kernel/rcu/tree.c:2092 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2310 [inline] rcu_core+0xba5/0x1500 kernel/rcu/tree.c:2291 __do_softirq+0x25c/0x94c kernel/softirq.c:293 invoke_softirq kernel/softirq.c:374 [inline] irq_exit+0x180/0x1d0 kernel/softirq.c:414 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x13b/0x550 arch/x86/kernel/apic/apic.c:1068 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:806 RIP: 0010:should_resched arch/x86/include/asm/preempt.h:102 [inline] RIP: 0010:__local_bh_enable_ip+0x18e/0x270 kernel/softirq.c:197 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 7f f6 6d 07 00 0f 84 8f 00 00 00 fb 66 0f 1f 44 00 00 <65> 8b 05 73 83 bd 7e 85 c0 74 7f 5b 41 5c 41 5d 5d c3 80 3d c0 40 RSP: 0018:ffff8880a8ad7b78 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff1164e10 RBX: 0000000000000201 RCX: 1ffff1101517d9be RDX: dffffc0000000000 RSI: ffff8880a8becdd0 RDI: ffff8880a8becd7c RBP: ffff8880a8ad7b90 R08: ffff8880a8bec500 R09: ffff8880a8becdf0 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff85f54821 R13: ffff8880a8bec500 R14: dffffc0000000000 R15: 0000000000000000 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:176 [inline] _raw_spin_unlock_bh+0x31/0x40 kernel/locking/spinlock.c:207 spin_unlock_bh include/linux/spinlock.h:383 [inline] tcp_metrics_flush_all+0x261/0x340 net/ipv4/tcp_metrics.c:893 tcp_net_metrics_exit_batch+0x10/0x20 net/ipv4/tcp_metrics.c:1012 ops_exit_list.isra.0+0xfc/0x150 net/core/net_namespace.c:157 cleanup_net+0x3fb/0x960 net/core/net_namespace.c:553 process_one_work+0x989/0x1790 kernel/workqueue.c:2269 worker_thread+0x98/0xe40 kernel/workqueue.c:2415 kthread+0x354/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Allocated by task 8986: save_stack+0x23/0x90 mm/kasan/common.c:71 set_track mm/kasan/common.c:79 [inline] __kasan_kmalloc mm/kasan/common.c:489 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:462 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:503 kmem_cache_alloc_trace+0x151/0x750 mm/slab.c:3555 kmalloc include/linux/slab.h:547 [inline] kzalloc include/linux/slab.h:742 [inline] fqdir_init include/net/inet_frag.h:115 [inline] ipv4_frags_init_net+0x48/0x4e0 net/ipv4/ip_fragment.c:645 ops_init+0xb3/0x410 net/core/net_namespace.c:130 setup_net+0x2d3/0x740 net/core/net_namespace.c:316 copy_net_ns+0x1df/0x340 net/core/net_namespace.c:439 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:2692 __do_sys_unshare kernel/fork.c:2760 [inline] __se_sys_unshare kernel/fork.c:2758 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:2758 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 14091: save_stack+0x23/0x90 mm/kasan/common.c:71 set_track mm/kasan/common.c:79 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:451 kasan_slab_free+0xe/0x10 mm/kasan/common.c:459 __cache_free mm/slab.c:3432 [inline] kfree+0xcf/0x220 mm/slab.c:3755 fqdir_rwork_fn+0x33/0x40 net/ipv4/inet_fragment.c:154 process_one_work+0x989/0x1790 kernel/workqueue.c:2269 worker_thread+0x98/0xe40 kernel/workqueue.c:2415 kthread+0x354/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 The buggy address belongs to the object at ffff8880969c4d00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 24 bytes inside of 512-byte region [ffff8880969c4d00, ffff8880969c4f00) The buggy address belongs to the page: page:ffffea00025a7100 refcount:1 mapcount:0 mapping:ffff8880aa400940 index:0x0 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea00022edcc8 ffffea00022928c8 ffff8880aa400940 raw: 0000000000000000 ffff8880969c4080 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880969c4c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880969c4c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880969c4d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880969c4d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880969c4e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================