================================================================== BUG: KASAN: use-after-free in inet_frag_destroy_rcu+0xd9/0xe0 net/ipv4/inet_fragment.c:201 Read of size 8 at addr ffff8880a5d52d58 by task syz-executor.0/6429 CPU: 0 PID: 6429 Comm: syz-executor.0 Not tainted 5.2.0-rc1+ #4 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:kernel_text_address+0x73/0xf0 kernel/extable.c:160 Code: 86 00 00 00 83 3d e0 f1 34 08 01 76 28 e8 25 57 13 00 84 c0 74 3e 4c 89 e7 e8 c9 13 1c 00 84 c0 75 25 4c 89 e7 e8 6d 88 30 00 <48> 83 c4 08 0f b6 c0 41 5c 5d c3 49 81 fc 00 f0 8c 89 72 cf 49 81 RSP: 0018:ffff888061bdf1f8 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 1ffff1100cd2e9ce RDX: dffffc0000000000 RSI: 1ffff1100cd2e9da RDI: 0000000000000282 RBP: ffff888061bdf208 R08: ffff888066974600 R09: 0000000000000003 R10: ffffed1015d06bdf R11: ffff8880ae835efb R12: 0000000000000000 R13: 0000000000000000 R14: ffff888066974600 R15: ffff88821bc48500 __kernel_text_address+0xd/0x40 kernel/extable.c:107 unwind_get_return_address arch/x86/kernel/unwind_frame.c:19 [inline] unwind_get_return_address+0x61/0xa0 arch/x86/kernel/unwind_frame.c:14 arch_stack_walk+0x97/0xf0 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0xac/0xe0 kernel/stacktrace.c:123 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_slab_alloc+0xf/0x20 mm/kasan/common.c:497 slab_post_alloc_hook mm/slab.h:437 [inline] slab_alloc mm/slab.c:3326 [inline] kmem_cache_alloc+0x11a/0x6f0 mm/slab.c:3488 kmem_cache_zalloc include/linux/slab.h:732 [inline] __kernfs_new_node+0xf0/0x6c0 fs/kernfs/dir.c:632 kernfs_new_node+0x96/0x120 fs/kernfs/dir.c:698 __kernfs_create_file+0x51/0x340 fs/kernfs/file.c:1002 sysfs_add_file_mode_ns+0x222/0x560 fs/sysfs/file.c:305 create_files fs/sysfs/group.c:63 [inline] internal_create_group+0x359/0xc40 fs/sysfs/group.c:148 sysfs_create_group fs/sysfs/group.c:174 [inline] sysfs_create_groups fs/sysfs/group.c:201 [inline] sysfs_create_groups+0x9b/0x141 fs/sysfs/group.c:191 device_add_groups drivers/base/core.c:1288 [inline] device_add_attrs drivers/base/core.c:1447 [inline] device_add+0x1353/0x17a0 drivers/base/core.c:2080 netdev_register_kobject+0x183/0x3b0 net/core/net-sysfs.c:1750 register_netdevice+0x875/0xff0 net/core/dev.c:8743 register_netdev+0x30/0x50 net/core/dev.c:8861 ip6_tnl_init_net+0x54a/0x860 net/ipv6/ip6_tunnel.c:2251 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 RIP: 0033:0x45bd47 Code: 00 00 00 b8 63 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 1d 8d fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 10 01 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 fd 8c fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fff94d882f8 EFLAGS: 00000206 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffda RBX: 000000000075c9a8 RCX: 000000000045bd47 RDX: 0000000000000000 RSI: 00007fff94d882a0 RDI: 0000000040000000 RBP: 00000000000000f8 R08: 0000000000000000 R09: 0000000000000005 R10: 0000000000000000 R11: 0000000000000206 R12: 000000000075c9a8 R13: 00007fff94d88568 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 9123: 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 5: 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 ffff8880a5d52d40 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 24 bytes inside of 512-byte region [ffff8880a5d52d40, ffff8880a5d52f40) The buggy address belongs to the page: page:ffffea0002975480 refcount:1 mapcount:0 mapping:ffff8880aa400940 index:0x0 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea00026bef48 ffffea00026b8208 ffff8880aa400940 raw: 0000000000000000 ffff8880a5d520c0 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a5d52c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880a5d52c80: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880a5d52d00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ^ ffff8880a5d52d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a5d52e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================