================================================================== BUG: KASAN: use-after-free in hlist_add_head include/linux/list.h:673 [inline] BUG: KASAN: use-after-free in enqueue_timer kernel/time/timer.c:520 [inline] BUG: KASAN: use-after-free in __mod_timer kernel/time/timer.c:1021 [inline] BUG: KASAN: use-after-free in mod_timer+0x11d3/0x15b0 kernel/time/timer.c:1071 Write of size 8 at addr ffff88019a10b808 by task syz-executor6/7022 CPU: 0 PID: 7022 Comm: syz-executor6 Not tainted 4.14.0-rc1-next-20170920+ #26 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:52 print_address_description+0x73/0x250 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report+0x24e/0x340 mm/kasan/report.c:409 __asan_report_store8_noabort+0x17/0x20 mm/kasan/report.c:435 hlist_add_head include/linux/list.h:673 [inline] enqueue_timer kernel/time/timer.c:520 [inline] __mod_timer kernel/time/timer.c:1021 [inline] mod_timer+0x11d3/0x15b0 kernel/time/timer.c:1071 sk_reset_timer+0x22/0x50 net/core/sock.c:2664 inet_csk_reset_xmit_timer include/net/inet_connection_sock.h:243 [inline] dccp_send_close+0x2ea/0x380 net/dccp/output.c:700 dccp_terminate_connection net/dccp/proto.c:974 [inline] dccp_close+0x8b6/0xc10 net/dccp/proto.c:1037 inet_release+0xed/0x1c0 net/ipv4/af_inet.c:425 sock_release+0x8d/0x1e0 net/socket.c:597 sock_close+0x16/0x20 net/socket.c:1126 __fput+0x333/0x7f0 fs/file_table.c:210 ____fput+0x15/0x20 fs/file_table.c:244 task_work_run+0x199/0x270 kernel/task_work.c:112 exit_task_work include/linux/task_work.h:21 [inline] do_exit+0xa52/0x1b40 kernel/exit.c:865 do_group_exit+0x149/0x400 kernel/exit.c:968 get_signal+0x7e8/0x17e0 kernel/signal.c:2334 do_signal+0x94/0x1ee0 arch/x86/kernel/signal.c:808 exit_to_usermode_loop+0x224/0x300 arch/x86/entry/common.c:158 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath+0x42f/0x510 arch/x86/entry/common.c:266 entry_SYSCALL_64_fastpath+0xbc/0xbe RIP: 0033:0x4520a9 RSP: 002b:00007f979d68bcf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00000000007180d8 RCX: 00000000004520a9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000007180d8 RBP: 00000000007180b0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000a6f7ef R14: 00007f979d68c9c0 R15: 0000000000000002 Allocated by task 6964: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551 __do_kmalloc_node mm/slab.c:3689 [inline] __kmalloc_node+0x47/0x70 mm/slab.c:3696 kmalloc_node include/linux/slab.h:535 [inline] kvmalloc_node+0x64/0xd0 mm/util.c:397 kvmalloc include/linux/mm.h:529 [inline] kvzalloc include/linux/mm.h:537 [inline] alloc_netdev_mqs+0x16e/0xed0 net/core/dev.c:8018 tun_set_iff drivers/net/tun.c:2022 [inline] __tun_chr_ioctl+0x12be/0x3d20 drivers/net/tun.c:2276 tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:2521 vfs_ioctl fs/ioctl.c:45 [inline] do_vfs_ioctl+0x1b1/0x1530 fs/ioctl.c:685 SYSC_ioctl fs/ioctl.c:700 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691 entry_SYSCALL_64_fastpath+0x1f/0xbe Freed by task 6964: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3503 [inline] kfree+0xca/0x250 mm/slab.c:3820 kvfree+0x36/0x60 mm/util.c:416 netdev_freemem net/core/dev.c:7970 [inline] free_netdev+0x2cf/0x360 net/core/dev.c:8132 tun_set_iff drivers/net/tun.c:2105 [inline] __tun_chr_ioctl+0x2cf6/0x3d20 drivers/net/tun.c:2276 tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:2521 vfs_ioctl fs/ioctl.c:45 [inline] do_vfs_ioctl+0x1b1/0x1530 fs/ioctl.c:685 SYSC_ioctl fs/ioctl.c:700 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691 entry_SYSCALL_64_fastpath+0x1f/0xbe The buggy address belongs to the object at ffff88019a108400 which belongs to the cache kmalloc-16384 of size 16384 The buggy address is located 13320 bytes inside of 16384-byte region [ffff88019a108400, ffff88019a10c400) The buggy address belongs to the page: page:ffffea0006684200 count:1 mapcount:0 mapping:ffff88019a108400 index:0x0 compound_mapcount: 0 flags: 0x200000000008100(slab|head) raw: 0200000000008100 ffff88019a108400 0000000000000000 0000000100000001 raw: ffffea0006681820 ffffea0006686620 ffff8801dac02200 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88019a10b700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88019a10b780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88019a10b800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88019a10b880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88019a10b900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================