executing program executing program syzkaller login: [ 22.756173] ================================================================== [ 22.756972] BUG: KASAN: use-after-free in __internal_add_timer+0x275/0x2d0 [ 22.757637] Write of size 8 at addr ffff880067c3b748 by task syzkaller255001/2957 [ 22.758354] [ 22.758512] CPU: 3 PID: 2957 Comm: syzkaller255001 Not tainted 4.13.0-next-20170913+ #3 [ 22.759353] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 [ 22.760120] Call Trace: [ 22.760377] dump_stack+0x194/0x257 [ 22.760704] ? arch_local_irq_restore+0x53/0x53 [ 22.761228] ? show_regs_print_info+0x65/0x65 [ 22.761718] ? __internal_add_timer+0x275/0x2d0 [ 22.762167] print_address_description+0x73/0x250 [ 22.762613] ? __internal_add_timer+0x275/0x2d0 [ 22.763103] kasan_report+0x24e/0x340 [ 22.763794] __asan_report_store8_noabort+0x17/0x20 [ 22.764708] __internal_add_timer+0x275/0x2d0 [ 22.765127] ? calc_wheel_index+0x200/0x200 [ 22.765561] mod_timer+0x622/0x15b0 [ 22.765903] ? mod_timer_pending+0x14e0/0x14e0 [ 22.766348] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 22.766808] ? trace_hardirqs_on+0xd/0x10 [ 22.767243] ? _crng_backtrack_protect+0xd9/0x130 [ 22.767732] ? __lock_is_held+0xbc/0x140 [ 22.768111] ? __lockdep_init_map+0xe4/0x650 [ 22.768545] ? lockdep_init_map+0x3d/0x70 [ 22.768936] ? rcu_read_lock_sched_held+0x108/0x120 [ 22.769428] ? init_timer_key+0x126/0x3b0 [ 22.769813] ? try_to_del_timer_sync+0x120/0x120 [ 22.770288] ? round_jiffies_up+0xce/0x100 [ 22.770742] ? __round_jiffies_up_relative+0x150/0x150 [ 22.771295] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 22.771886] __tun_chr_ioctl+0x1b23/0x3d20 [ 22.772307] ? tun_chr_read_iter+0x1e0/0x1e0 [ 22.772749] ? lock_downgrade+0x990/0x990 [ 22.773193] ? check_same_owner+0x320/0x320 [ 22.773668] ? __handle_mm_fault+0x39c0/0x39c0 [ 22.774075] ? vmacache_find+0x61/0x270 [ 22.774466] ? tun_chr_compat_ioctl+0x30/0x30 [ 22.774863] tun_chr_ioctl+0x2a/0x40 [ 22.775195] ? tun_chr_ioctl+0x2a/0x40 [ 22.775572] do_vfs_ioctl+0x1b1/0x1530 [ 22.775926] ? ioctl_preallocate+0x2b0/0x2b0 [ 22.776349] ? selinux_capable+0x40/0x40 [ 22.776718] ? putname+0xf3/0x130 [ 22.777096] ? do_sys_open+0x320/0x6d0 [ 22.777536] ? security_file_ioctl+0x7d/0xb0 [ 22.777934] ? security_file_ioctl+0x89/0xb0 [ 22.778365] SyS_ioctl+0x8f/0xc0 [ 22.778680] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 22.779226] RIP: 0033:0x439089 [ 22.779547] RSP: 002b:00007ffd84f517a8 EFLAGS: 00000206 ORIG_RAX: 0000000000000010 [ 22.780268] RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 0000000000439089 [ 22.780984] RDX: 0000000020f5efd8 RSI: 00000000400454ca RDI: 0000000000000004 [ 22.781768] RBP: 0000000000000082 R08: 00000000000000fd R09: 0000000000000000 [ 22.782507] R10: 0000000000000000 R11: 0000000000000206 R12: 0d692084904f29db [ 22.783212] R13: 74656e2f7665642f R14: 0000000000401d70 R15: 0000000000000000 [ 22.783981] [ 22.784138] Allocated by task 2957: [ 22.784483] save_stack_trace+0x16/0x20 [ 22.784909] save_stack+0x43/0xd0 [ 22.785773] kasan_kmalloc+0xad/0xe0 [ 22.786149] __kmalloc_node+0x47/0x70 [ 22.786525] kvmalloc_node+0x64/0xd0 [ 22.786895] alloc_netdev_mqs+0x16e/0xed0 [ 22.787303] __tun_chr_ioctl+0x12be/0x3d20 [ 22.787731] tun_chr_ioctl+0x2a/0x40 [ 22.788067] do_vfs_ioctl+0x1b1/0x1530 [ 22.788502] SyS_ioctl+0x8f/0xc0 [ 22.788858] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 22.789418] [ 22.789616] Freed by task 2957: [ 22.789958] save_stack_trace+0x16/0x20 [ 22.790421] save_stack+0x43/0xd0 [ 22.790839] kasan_slab_free+0x71/0xc0 [ 22.791293] kfree+0xca/0x250 [ 22.791653] kvfree+0x36/0x60 [ 22.792027] free_netdev+0x2cf/0x360 [ 22.792456] __tun_chr_ioctl+0x2cf6/0x3d20 [ 22.792967] tun_chr_ioctl+0x2a/0x40 [ 22.793493] do_vfs_ioctl+0x1b1/0x1530 [ 22.793951] SyS_ioctl+0x8f/0xc0 [ 22.794328] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 22.794887] [ 22.795069] The buggy address belongs to the object at ffff880067c38340 [ 22.795069] which belongs to the cache kmalloc-16384 of size 16384 [ 22.796432] The buggy address is located 13320 bytes inside of [ 22.796432] 16384-byte region [ffff880067c38340, ffff880067c3c340) [ 22.797726] The buggy address belongs to the page: [ 22.798065] page:ffffea00019f0e00 count:1 mapcount:0 mapping:ffff880067c38340 index:0x0 compound_mapcount: 0 [ 22.798772] flags: 0x500000000008100(slab|head) [ 22.799137] raw: 0500000000008100 ffff880067c38340 0000000000000000 0000000100000001 [ 22.799734] raw: ffffea0001a87620 ffffea0001b25c20 ffff88003e802200 0000000000000000 [ 22.800292] page dumped because: kasan: bad access detected [ 22.800707] [ 22.800832] Memory state around the buggy address: [ 22.801227] ffff880067c3b600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 22.801760] ffff880067c3b680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 22.802303] >ffff880067c3b700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 22.802849] ^ [ 22.803269] ffff880067c3b780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 22.803816] ffff880067c3b800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 22.804373] ================================================================== [ 22.804922] Disabling lock debugging due to kernel taint [ 22.805347] Kernel panic - not syncing: panic_on_warn set ... [ 22.805347] [ 22.805870] CPU: 3 PID: 2957 Comm: syzkaller255001 Tainted: G B 4.13.0-next-20170913+ #3 [ 22.806965] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 [ 22.807797] Call Trace: [ 22.807987] dump_stack+0x194/0x257 [ 22.808263] ? arch_local_irq_restore+0x53/0x53 [ 22.808611] ? vprintk_default+0x28/0x30 [ 22.808925] ? __internal_add_timer+0x1f0/0x2d0 [ 22.809296] panic+0x1e4/0x417 [ 22.809515] ? __warn+0x1d9/0x1d9 [ 22.809782] ? __internal_add_timer+0x275/0x2d0 [ 22.810109] kasan_end_report+0x50/0x50 [ 22.810472] kasan_report+0x137/0x340 [ 22.810821] __asan_report_store8_noabort+0x17/0x20 [ 22.811271] __internal_add_timer+0x275/0x2d0 [ 22.811678] ? calc_wheel_index+0x200/0x200 [ 22.812127] mod_timer+0x622/0x15b0 [ 22.812485] ? mod_timer_pending+0x14e0/0x14e0 [ 22.812902] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 22.813391] ? trace_hardirqs_on+0xd/0x10 [ 22.813767] ? _crng_backtrack_protect+0xd9/0x130 [ 22.814198] ? __lock_is_held+0xbc/0x140 [ 22.814563] ? __lockdep_init_map+0xe4/0x650 [ 22.814957] ? lockdep_init_map+0x3d/0x70 [ 22.815326] ? rcu_read_lock_sched_held+0x108/0x120 [ 22.815771] ? init_timer_key+0x126/0x3b0 [ 22.816141] ? try_to_del_timer_sync+0x120/0x120 [ 22.816564] ? round_jiffies_up+0xce/0x100 [ 22.816961] ? __round_jiffies_up_relative+0x150/0x150 [ 22.817466] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 22.817917] __tun_chr_ioctl+0x1b23/0x3d20 [ 22.818303] ? tun_chr_read_iter+0x1e0/0x1e0 [ 22.818705] ? lock_downgrade+0x990/0x990 [ 22.819089] ? check_same_owner+0x320/0x320 [ 22.819479] ? __handle_mm_fault+0x39c0/0x39c0 [ 22.819892] ? vmacache_find+0x61/0x270 [ 22.820252] ? tun_chr_compat_ioctl+0x30/0x30 [ 22.820660] tun_chr_ioctl+0x2a/0x40 [ 22.820998] ? tun_chr_ioctl+0x2a/0x40 [ 22.821377] do_vfs_ioctl+0x1b1/0x1530 [ 22.821733] ? ioctl_preallocate+0x2b0/0x2b0 [ 22.822129] ? selinux_capable+0x40/0x40 [ 22.822497] ? putname+0xf3/0x130 [ 22.822810] ? do_sys_open+0x320/0x6d0 [ 22.823161] ? security_file_ioctl+0x7d/0xb0 [ 22.823558] ? security_file_ioctl+0x89/0xb0 [ 22.823957] SyS_ioctl+0x8f/0xc0 [ 22.824263] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 22.824694] RIP: 0033:0x439089 [ 22.824981] RSP: 002b:00007ffd84f517a8 EFLAGS: 00000206 ORIG_RAX: 0000000000000010 [ 22.825704] RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 0000000000439089 [ 22.826352] RDX: 0000000020f5efd8 RSI: 00000000400454ca RDI: 0000000000000004 [ 22.827002] RBP: 0000000000000082 R08: 00000000000000fd R09: 0000000000000000 [ 22.827654] R10: 0000000000000000 R11: 0000000000000206 R12: 0d692084904f29db [ 22.828268] R13: 74656e2f7665642f R14: 0000000000401d70 R15: 0000000000000000 [ 22.829697] Dumping ftrace buffer: [ 22.830017] (ftrace buffer empty) [ 22.830350] Kernel Offset: disabled [ 22.830680] Rebooting in 86400 seconds..