================================================================== BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:26 [inline] BUG: KASAN: use-after-free in refcount_inc_not_zero_checked+0x81/0x200 lib/refcount.c:123 Read of size 4 at addr ffff888058738180 by task syz-executor.4/16108 CPU: 1 PID: 16108 Comm: syz-executor.4 Not tainted 5.3.0-rc2+ #82 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+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 check_memory_region_inline mm/kasan/generic.c:185 [inline] check_memory_region+0x134/0x1a0 mm/kasan/generic.c:192 __kasan_check_read+0x11/0x20 mm/kasan/common.c:92 atomic_read include/asm-generic/atomic-instrumented.h:26 [inline] refcount_inc_not_zero_checked+0x81/0x200 lib/refcount.c:123 refcount_inc_checked+0x17/0x70 lib/refcount.c:156 sock_hold include/net/sock.h:649 [inline] sk_add_node include/net/sock.h:701 [inline] nr_insert_socket+0x2d/0xe0 net/netrom/af_netrom.c:137 nr_rx_frame+0x1605/0x1e73 net/netrom/af_netrom.c:1023 nr_loopback_timer+0x7b/0x170 net/netrom/nr_loopback.c:59 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 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:537 [inline] smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1095 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:828 RIP: 0010:sysfs_add_file_mode_ns+0x98/0x560 fs/sysfs/file.c:256 Code: 00 00 00 00 fc ff df 48 8d 78 28 48 89 f9 48 c1 e9 03 80 3c 11 00 0f 85 57 04 00 00 48 ba 00 00 00 00 00 fc ff df 4c 8b 78 28 <49> 8d 7f 08 48 89 f9 48 c1 e9 03 80 3c 11 00 0f 85 18 04 00 00 4d RSP: 0018:ffff888055b9f528 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffff888055908ea0 RBX: ffffffff89798240 RCX: 1ffff1100ab211d9 RDX: dffffc0000000000 RSI: ffffffff81dbcf50 RDI: ffff888055908ec8 RBP: ffff888055b9f568 R08: ffff88809766a080 R09: 0000000000000000 R10: fffffbfff11d4144 R11: ffffffff88ea0a27 R12: ffff8880a8fb5700 R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff892e1660 create_files fs/sysfs/group.c:63 [inline] internal_create_group+0x359/0xc30 fs/sysfs/group.c:148 internal_create_groups.part.0+0x90/0x140 fs/sysfs/group.c:188 internal_create_groups fs/sysfs/group.c:184 [inline] sysfs_create_groups+0x2a/0x50 fs/sysfs/group.c:214 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:2083 netdev_register_kobject+0x183/0x3b0 net/core/net-sysfs.c:1746 register_netdevice+0x875/0xf10 net/core/dev.c:8723 ip6_tnl_create2+0x1c2/0x350 net/ipv6/ip6_tunnel.c:264 ip6_tnl_create net/ipv6/ip6_tunnel.c:315 [inline] ip6_tnl_locate+0x63f/0x8d0 net/ipv6/ip6_tunnel.c:363 ip6_tnl_ioctl+0x496/0xac0 net/ipv6/ip6_tunnel.c:1629 dev_ifsioc+0x743/0xa00 net/core/dev_ioctl.c:322 dev_ioctl+0x286/0xc74 net/core/dev_ioctl.c:514 sock_ioctl+0x5d2/0x790 net/socket.c:1103 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459829 Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ff44dfdac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459829 RDX: 0000000020000080 RSI: 00000000000089f1 RDI: 0000000000000007 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff44dfdb6d4 R13: 00000000004cd2c0 R14: 00000000004d68d8 R15: 00000000ffffffff Allocated by task 16108: 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_kmalloc+0x9/0x10 mm/kasan/common.c:501 __do_kmalloc mm/slab.c:3655 [inline] __kmalloc+0x163/0x770 mm/slab.c:3664 kmalloc include/linux/slab.h:557 [inline] sk_prot_alloc+0x23a/0x310 net/core/sock.c:1603 sk_alloc+0x39/0xf70 net/core/sock.c:1657 nr_make_new net/netrom/af_netrom.c:476 [inline] nr_rx_frame+0x733/0x1e73 net/netrom/af_netrom.c:959 nr_loopback_timer+0x7b/0x170 net/netrom/nr_loopback.c:59 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 Freed by task 16123: 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] kfree+0x10a/0x2c0 mm/slab.c:3756 sk_prot_free net/core/sock.c:1640 [inline] __sk_destruct+0x4f7/0x6e0 net/core/sock.c:1726 sk_destruct+0x86/0xa0 net/core/sock.c:1734 __sk_free+0xfb/0x360 net/core/sock.c:1745 sk_free+0x42/0x50 net/core/sock.c:1756 sock_put include/net/sock.h:1725 [inline] sock_efree+0x61/0x80 net/core/sock.c:2042 skb_release_head_state+0xeb/0x250 net/core/skbuff.c:652 skb_release_all+0x16/0x60 net/core/skbuff.c:663 __kfree_skb net/core/skbuff.c:679 [inline] kfree_skb net/core/skbuff.c:697 [inline] kfree_skb+0x101/0x3c0 net/core/skbuff.c:691 nr_accept+0x56e/0x700 net/netrom/af_netrom.c:819 __sys_accept4+0x34e/0x6a0 net/socket.c:1754 __do_sys_accept net/socket.c:1795 [inline] __se_sys_accept net/socket.c:1792 [inline] __x64_sys_accept+0x75/0xb0 net/socket.c:1792 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff888058738100 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 128 bytes inside of 2048-byte region [ffff888058738100, ffff888058738900) The buggy address belongs to the page: page:ffffea000161ce00 refcount:1 mapcount:0 mapping:ffff8880aa400e00 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea000180af08 ffffea0001636588 ffff8880aa400e00 raw: 0000000000000000 ffff888058738100 0000000100000003 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888058738080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888058738100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888058738180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888058738200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888058738280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================