================================================================== BUG: KASAN: use-after-free in inet_frag_destroy_rcu+0xd9/0xe0 net/ipv4/inet_fragment.c:201 Read of size 8 at addr ffff8880a46a25d8 by task syz-executor.1/9012 CPU: 0 PID: 9012 Comm: syz-executor.1 Not tainted 5.2.0-rc2-next-20190529 #2 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 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:arch_local_irq_restore arch/x86/include/asm/paravirt.h:767 [inline] RIP: 0010:lock_acquire+0x1ea/0x3f0 kernel/locking/lockdep.c:4303 Code: 84 08 00 00 00 00 00 00 48 c1 e8 03 80 3c 10 00 0f 85 c4 01 00 00 48 83 3d a2 d7 7a 07 00 0f 84 38 01 00 00 48 8b 7d c8 57 9d <0f> 1f 44 00 00 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 65 8b RSP: 0018:ffff88808b92ed00 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff11a4e8e RBX: ffff88809397e100 RCX: ffff88809397e988 RDX: dffffc0000000000 RSI: 0000000000000001 RDI: 0000000000000286 RBP: ffff88808b92ed48 R08: 00000000e93eea39 R09: ffff88809397e9f8 R10: ffff88809397e9d8 R11: ffff88809397e100 R12: ffffffff88da3740 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000002 rcu_lock_acquire include/linux/rcupdate.h:210 [inline] rcu_read_lock include/linux/rcupdate.h:595 [inline] list_lru_count_one+0x66/0x380 mm/list_lru.c:194 list_lru_shrink_count include/linux/list_lru.h:122 [inline] super_cache_count+0x14c/0x2e0 fs/super.c:146 do_shrink_slab+0x109/0xa70 mm/vmscan.c:469 shrink_slab_memcg mm/vmscan.c:616 [inline] shrink_slab+0x36a/0x5e0 mm/vmscan.c:688 shrink_node+0x5f9/0x1660 mm/vmscan.c:2720 shrink_zones mm/vmscan.c:2949 [inline] do_try_to_free_pages+0x3cb/0x11e0 mm/vmscan.c:3007 try_to_free_mem_cgroup_pages+0x2dd/0x9f0 mm/vmscan.c:3302 try_charge+0x5bd/0x1790 mm/memcontrol.c:2349 __memcg_kmem_charge_memcg+0x7c/0x130 mm/memcontrol.c:2713 memcg_kmem_charge_memcg include/linux/memcontrol.h:1339 [inline] memcg_charge_slab mm/slab.h:282 [inline] kmem_getpages mm/slab.c:1379 [inline] cache_grow_begin+0x402/0x650 mm/slab.c:2606 fallback_alloc+0x1fd/0x2d0 mm/slab.c:3153 ____cache_alloc_node+0x1be/0x1e0 mm/slab.c:3221 __do_cache_alloc mm/slab.c:3290 [inline] slab_alloc mm/slab.c:3318 [inline] kmem_cache_alloc+0x1e8/0x6f0 mm/slab.c:3488 ext4_alloc_inode+0x1f/0x640 fs/ext4/super.c:1073 alloc_inode+0x68/0x1e0 fs/inode.c:227 iget_locked+0x196/0x4a0 fs/inode.c:1181 __ext4_iget+0x273/0x3f10 fs/ext4/inode.c:4847 ext4_lookup fs/ext4/namei.c:1649 [inline] ext4_lookup+0x39e/0x760 fs/ext4/namei.c:1624 __lookup_slow+0x279/0x500 fs/namei.c:1669 lookup_slow+0x58/0x80 fs/namei.c:1686 mountpoint_last fs/namei.c:2663 [inline] path_mountpoint+0x5d2/0x1e60 fs/namei.c:2693 filename_mountpoint+0x190/0x3c0 fs/namei.c:2715 user_path_mountpoint_at+0x3a/0x50 fs/namei.c:2745 ksys_umount+0x167/0xf00 fs/namespace.c:1688 __do_sys_umount fs/namespace.c:1714 [inline] __se_sys_umount fs/namespace.c:1712 [inline] __x64_sys_umount+0x54/0x80 fs/namespace.c:1712 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45bca7 Code: 64 89 04 25 d0 02 00 00 58 5f ff d0 48 89 c7 e8 2f be ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 a6 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 9d 8d fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffe4d680308 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6 RAX: ffffffffffffffda RBX: 0000555555d11940 RCX: 000000000045bca7 RDX: 00000000004036a0 RSI: 0000000000000002 RDI: 00007ffe4d6803b0 RBP: 00000000000006fc R08: 0000000000000000 R09: 0000000000000010 R10: 000000000000000a R11: 0000000000000202 R12: 00007ffe4d681440 R13: 0000555555d11940 R14: 0000000000000000 R15: 00007ffe4d681440 Allocated by task 9020: 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] ipv6_frags_init_net+0x48/0x460 net/ipv6/reassembly.c:513 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:2719 __do_sys_unshare kernel/fork.c:2787 [inline] __se_sys_unshare kernel/fork.c:2785 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:2785 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 15494: 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 ffff8880a46a25c0 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 24 bytes inside of 512-byte region [ffff8880a46a25c0, ffff8880a46a27c0) The buggy address belongs to the page: page:ffffea000291a880 refcount:1 mapcount:0 mapping:ffff8880aa400940 index:0x0 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea0002412808 ffffea000235fcc8 ffff8880aa400940 raw: 0000000000000000 ffff8880a46a20c0 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a46a2480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a46a2500: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >ffff8880a46a2580: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ^ ffff8880a46a2600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a46a2680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================