executing program executing program syzkaller login: [ 48.094538] ================================================================== [ 48.095375] BUG: KASAN: use-after-free in __internal_add_timer+0x275/0x2d0 [ 48.095853] Write of size 8 at addr ffff8800691d3748 by task syzkaller858960/3031 [ 48.096567] [ 48.096723] CPU: 2 PID: 3031 Comm: syzkaller858960 Not tainted 4.13.0-next-20170908+ #18 [ 48.097487] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 [ 48.098235] Call Trace: [ 48.098482] dump_stack+0x194/0x257 [ 48.098823] ? arch_local_irq_restore+0x53/0x53 [ 48.099256] ? show_regs_print_info+0x65/0x65 [ 48.099676] ? __kernel_text_address+0xae/0xe0 [ 48.100116] ? __internal_add_timer+0x275/0x2d0 [ 48.100533] print_address_description+0x73/0x250 [ 48.100977] ? __internal_add_timer+0x275/0x2d0 [ 48.101434] kasan_report+0x24e/0x340 [ 48.101786] __asan_report_store8_noabort+0x17/0x20 [ 48.102244] __internal_add_timer+0x275/0x2d0 [ 48.102659] ? calc_wheel_index+0x200/0x200 [ 48.103060] mod_timer+0x622/0x15b0 [ 48.103401] ? mod_timer_pending+0x14e0/0x14e0 [ 48.103799] ? __lock_is_held+0xbc/0x140 [ 48.104196] ? __lock_is_held+0xbc/0x140 [ 48.104706] ? __lockdep_init_map+0xe4/0x650 [ 48.105422] ? lockdep_init_map+0x3d/0x70 [ 48.105807] ? rcu_read_lock_sched_held+0x108/0x120 [ 48.106291] ? init_timer_key+0x126/0x3b0 [ 48.106672] ? try_to_del_timer_sync+0x120/0x120 [ 48.107106] ? round_jiffies_up+0xce/0x100 [ 48.107496] ? __round_jiffies_up_relative+0x150/0x150 [ 48.107979] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 48.108449] ? selinux_tun_dev_alloc_security+0x124/0x170 [ 48.108958] __tun_chr_ioctl+0x1b23/0x3d20 [ 48.109353] ? tun_chr_read_iter+0x1e0/0x1e0 [ 48.109763] ? lock_downgrade+0x990/0x990 [ 48.110163] ? check_same_owner+0x320/0x320 [ 48.110558] ? __handle_mm_fault+0x39c0/0x39c0 [ 48.110974] ? vmacache_find+0x61/0x270 [ 48.111362] ? tun_chr_compat_ioctl+0x30/0x30 [ 48.111774] tun_chr_ioctl+0x2a/0x40 [ 48.112121] ? tun_chr_ioctl+0x2a/0x40 [ 48.112496] do_vfs_ioctl+0x1b1/0x1530 [ 48.112855] ? ioctl_preallocate+0x2b0/0x2b0 [ 48.113262] ? selinux_capable+0x40/0x40 [ 48.113636] ? putname+0xf3/0x130 [ 48.113956] ? do_sys_open+0x320/0x6d0 [ 48.114321] ? security_file_ioctl+0x7d/0xb0 [ 48.114722] ? security_file_ioctl+0x89/0xb0 [ 48.115128] SyS_ioctl+0x8f/0xc0 [ 48.115444] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 48.115857] RIP: 0033:0x438fd9 [ 48.116154] RSP: 002b:00007fff7c678798 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 [ 48.116842] RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 0000000000438fd9 [ 48.117485] RDX: 0000000020001000 RSI: 00000000400454ca RDI: 0000000000000004 [ 48.118127] RBP: 0000000000000082 R08: 00000000000000fd R09: 0000000000000000 [ 48.118787] R10: 0000000000000000 R11: 0000000000000202 R12: bc19fa32c7263647 [ 48.119431] R13: 74656e2f7665642f R14: 0000000000401cc0 R15: 0000000000000000 [ 48.120105] [ 48.120259] Allocated by task 3031: [ 48.120609] save_stack_trace+0x16/0x20 [ 48.120972] save_stack+0x43/0xd0 [ 48.121291] kasan_kmalloc+0xad/0xe0 [ 48.121634] __kmalloc_node+0x47/0x70 [ 48.121980] kvmalloc_node+0x64/0xd0 [ 48.122317] alloc_netdev_mqs+0x16e/0xed0 [ 48.122692] __tun_chr_ioctl+0x12be/0x3d20 [ 48.123094] tun_chr_ioctl+0x2a/0x40 [ 48.123445] do_vfs_ioctl+0x1b1/0x1530 [ 48.123801] SyS_ioctl+0x8f/0xc0 [ 48.124117] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 48.124544] [ 48.124696] Freed by task 3031: [ 48.124996] save_stack_trace+0x16/0x20 [ 48.125361] save_stack+0x43/0xd0 [ 48.125681] kasan_slab_free+0x71/0xc0 [ 48.126036] kfree+0xca/0x250 [ 48.126312] kvfree+0x36/0x60 [ 48.126604] free_netdev+0x2cf/0x360 [ 48.126948] __tun_chr_ioctl+0x2cf6/0x3d20 [ 48.127339] tun_chr_ioctl+0x2a/0x40 [ 48.127984] do_vfs_ioctl+0x1b1/0x1530 [ 48.128359] SyS_ioctl+0x8f/0xc0 [ 48.128630] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 48.129016] [ 48.129162] The buggy address belongs to the object at ffff8800691d0340 [ 48.129162] which belongs to the cache kmalloc-16384 of size 16384 [ 48.130127] The buggy address is located 13320 bytes inside of [ 48.130127] 16384-byte region [ffff8800691d0340, ffff8800691d4340) [ 48.131033] The buggy address belongs to the page: [ 48.131415] page:ffffea0001a47400 count:1 mapcount:0 mapping:ffff8800691d0340 index:0x0 compound_mapcount: 0 [ 48.132179] flags: 0x500000000008100(slab|head) [ 48.132541] raw: 0500000000008100 ffff8800691d0340 0000000000000000 0000000100000001 [ 48.133150] raw: ffffea0001a7a820 ffffea0001af2220 ffff88003e802200 0000000000000000 [ 48.133757] page dumped because: kasan: bad access detected [ 48.134257] [ 48.134378] Memory state around the buggy address: [ 48.134691] ffff8800691d3600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.135138] ffff8800691d3680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.135614] >ffff8800691d3700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.136075] ^ [ 48.136443] ffff8800691d3780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.136926] ffff8800691d3800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.137371] ================================================================== [ 48.137825] Disabling lock debugging due to kernel taint [ 48.138160] Kernel panic - not syncing: panic_on_warn set ... [ 48.138160] [ 48.138636] CPU: 2 PID: 3031 Comm: syzkaller858960 Tainted: G B 4.13.0-next-20170908+ #18 [ 48.139219] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 [ 48.139715] Call Trace: [ 48.139891] dump_stack+0x194/0x257 [ 48.140387] ? arch_local_irq_restore+0x53/0x53 [ 48.140731] ? vprintk_default+0x28/0x30 [ 48.141035] ? __internal_add_timer+0x270/0x2d0 [ 48.141379] panic+0x1e4/0x417 [ 48.141625] ? __warn+0x1d9/0x1d9 [ 48.141887] ? __internal_add_timer+0x275/0x2d0 [ 48.142237] kasan_end_report+0x50/0x50 [ 48.142521] kasan_report+0x137/0x340 [ 48.142797] __asan_report_store8_noabort+0x17/0x20 [ 48.143159] __internal_add_timer+0x275/0x2d0 [ 48.143502] ? calc_wheel_index+0x200/0x200 [ 48.143850] mod_timer+0x622/0x15b0 [ 48.144121] ? mod_timer_pending+0x14e0/0x14e0 [ 48.144461] ? __lock_is_held+0xbc/0x140 [ 48.144770] ? __lock_is_held+0xbc/0x140 [ 48.145062] ? __lockdep_init_map+0xe4/0x650 [ 48.145384] ? lockdep_init_map+0x3d/0x70 [ 48.145690] ? rcu_read_lock_sched_held+0x108/0x120 [ 48.146058] ? init_timer_key+0x126/0x3b0 [ 48.146362] ? try_to_del_timer_sync+0x120/0x120 [ 48.146708] ? round_jiffies_up+0xce/0x100 [ 48.147013] ? __round_jiffies_up_relative+0x150/0x150 [ 48.147415] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 48.148165] ? selinux_tun_dev_alloc_security+0x124/0x170 [ 48.148574] __tun_chr_ioctl+0x1b23/0x3d20 [ 48.148888] ? tun_chr_read_iter+0x1e0/0x1e0 [ 48.149228] ? lock_downgrade+0x990/0x990 [ 48.149552] ? check_same_owner+0x320/0x320 [ 48.149870] ? __handle_mm_fault+0x39c0/0x39c0 [ 48.150198] ? vmacache_find+0x61/0x270 [ 48.150509] ? tun_chr_compat_ioctl+0x30/0x30 [ 48.150851] tun_chr_ioctl+0x2a/0x40 [ 48.151125] ? tun_chr_ioctl+0x2a/0x40 [ 48.151417] do_vfs_ioctl+0x1b1/0x1530 [ 48.151702] ? ioctl_preallocate+0x2b0/0x2b0 [ 48.152032] ? selinux_capable+0x40/0x40 [ 48.152337] ? putname+0xf3/0x130 [ 48.152580] ? do_sys_open+0x320/0x6d0 [ 48.152875] ? security_file_ioctl+0x7d/0xb0 [ 48.153188] ? security_file_ioctl+0x89/0xb0 [ 48.153530] SyS_ioctl+0x8f/0xc0 [ 48.153781] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 48.154139] RIP: 0033:0x438fd9 [ 48.154381] RSP: 002b:00007fff7c678798 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 [ 48.154943] RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 0000000000438fd9 [ 48.155474] RDX: 0000000020001000 RSI: 00000000400454ca RDI: 0000000000000004 [ 48.156037] RBP: 0000000000000082 R08: 00000000000000fd R09: 0000000000000000 [ 48.156576] R10: 0000000000000000 R11: 0000000000000202 R12: bc19fa32c7263647 [ 48.157105] R13: 74656e2f7665642f R14: 0000000000401cc0 R15: 0000000000000000 [ 48.157776] Dumping ftrace buffer: [ 48.158045] (ftrace buffer empty) [ 48.158325] Kernel Offset: disabled [ 48.158596] Rebooting in 86400 seconds..