INIT: Entering runlevel: 2 [[36minfo[39;49m] Using makefile-style concurrent boot in runlevel 2. [....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added 'ci-upstream-kasan-gce-386-4,10.128.15.220' (ECDSA) to the list of known hosts. executing program executing program syzkaller login: [ 40.891864] ================================================================== [ 40.893019] BUG: KASAN: use-after-free in __internal_add_timer+0x275/0x2d0 [ 40.893945] Write of size 8 at addr ffff8801c02e3688 by task syzkaller235809/2982 [ 40.894946] [ 40.895183] CPU: 0 PID: 2982 Comm: syzkaller235809 Not tainted 4.14.0-rc2+ #20 [ 40.896169] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 40.897391] Call Trace: [ 40.897754] dump_stack+0x194/0x257 [ 40.898251] ? arch_local_irq_restore+0x53/0x53 [ 40.898876] ? show_regs_print_info+0x65/0x65 [ 40.899488] ? __kernel_text_address+0xd/0x40 [ 40.900092] ? __internal_add_timer+0x275/0x2d0 [ 40.900721] print_address_description+0x73/0x250 [ 40.901369] ? __internal_add_timer+0x275/0x2d0 [ 40.901996] kasan_report+0x25b/0x340 [ 40.902544] __asan_report_store8_noabort+0x17/0x20 [ 40.903213] __internal_add_timer+0x275/0x2d0 [ 40.903820] ? calc_wheel_index+0x200/0x200 [ 40.904423] mod_timer+0x622/0x15b0 [ 40.904927] ? mod_timer_pending+0x14e0/0x14e0 [ 40.905545] ? __lock_is_held+0xbc/0x140 [ 40.906108] ? __lock_is_held+0xbc/0x140 [ 40.906659] ? __lockdep_init_map+0xe4/0x650 [ 40.907255] ? lockdep_init_map+0x3d/0x70 [ 40.907814] ? rcu_read_lock_sched_held+0x108/0x120 [ 40.908484] ? init_timer_key+0x126/0x3b0 [ 40.909047] ? try_to_del_timer_sync+0x120/0x120 [ 40.909687] ? round_jiffies_up+0xce/0x100 [ 40.910260] ? __round_jiffies_up_relative+0x150/0x150 [ 40.910969] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 40.911629] ? selinux_tun_dev_alloc_security+0x124/0x170 [ 40.914516] __tun_chr_ioctl+0x1b23/0x3d20 [ 40.918730] ? tun_chr_read_iter+0x1e0/0x1e0 [ 40.923111] ? __pmd_alloc+0x4e0/0x4e0 [ 40.926973] ? __might_sleep+0x95/0x190 [ 40.930928] ? selinux_file_ioctl+0x444/0x690 [ 40.935393] ? __fget_light+0x29d/0x390 [ 40.939340] ? selinux_capable+0x40/0x40 [ 40.943395] tun_chr_compat_ioctl+0x29/0x30 [ 40.947686] ? tun_chr_compat_ioctl+0x29/0x30 [ 40.952154] compat_SyS_ioctl+0x1d7/0x3290 [ 40.956357] ? __handle_mm_fault+0x39c0/0x39c0 [ 40.960912] ? __tun_chr_ioctl+0x3d20/0x3d20 [ 40.965293] ? do_ioctl+0x60/0x60 [ 40.968721] ? do_fast_syscall_32+0x158/0xf05 [ 40.973188] ? do_ioctl+0x60/0x60 [ 40.976612] do_fast_syscall_32+0x3f2/0xf05 [ 40.980913] ? do_int80_syscall_32+0x940/0x940 [ 40.985468] ? kasan_check_read+0x11/0x20 [ 40.989588] ? syscall_return_slowpath+0x510/0x510 [ 40.994489] ? SyS_rt_sigaction+0x94/0x1b0 [ 40.998696] ? lockdep_sys_exit+0x47/0xf0 [ 41.002814] ? retint_user+0x18/0x20 [ 41.006502] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 41.011324] entry_SYSENTER_compat+0x51/0x60 [ 41.015701] RIP: 0023:0xf7fd8c79 [ 41.019035] RSP: 002b:00000000ff9db9dc EFLAGS: 00000286 ORIG_RAX: 0000000000000036 [ 41.026713] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00000000400454ca [ 41.033954] RDX: 0000000020bc5000 RSI: 00000000080ef00c RDI: 000000000000003f [ 41.041194] RBP: 0000000000001000 R08: 0000000000000000 R09: 0000000000000000 [ 41.048433] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 41.055681] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 41.062941] [ 41.064539] Allocated by task 2982: [ 41.068139] save_stack_trace+0x16/0x20 [ 41.072082] save_stack+0x43/0xd0 [ 41.075504] kasan_kmalloc+0xad/0xe0 [ 41.079186] __kmalloc_node+0x47/0x70 [ 41.082957] kvmalloc_node+0x64/0xd0 [ 41.086643] alloc_netdev_mqs+0x16e/0xed0 [ 41.090759] __tun_chr_ioctl+0x12be/0x3d20 [ 41.094963] tun_chr_compat_ioctl+0x29/0x30 [ 41.099253] compat_SyS_ioctl+0x1d7/0x3290 [ 41.103457] do_fast_syscall_32+0x3f2/0xf05 [ 41.107746] entry_SYSENTER_compat+0x51/0x60 [ 41.112118] [ 41.113714] Freed by task 2982: [ 41.116961] save_stack_trace+0x16/0x20 [ 41.120902] save_stack+0x43/0xd0 [ 41.124324] kasan_slab_free+0x71/0xc0 [ 41.128179] kfree+0xca/0x250 [ 41.131254] kvfree+0x36/0x60 [ 41.134330] free_netdev+0x2cf/0x360 [ 41.138012] __tun_chr_ioctl+0x2cf6/0x3d20 [ 41.142214] tun_chr_compat_ioctl+0x29/0x30 [ 41.146504] compat_SyS_ioctl+0x1d7/0x3290 [ 41.150706] do_fast_syscall_32+0x3f2/0xf05 [ 41.154994] entry_SYSENTER_compat+0x51/0x60 [ 41.159367] [ 41.160966] The buggy address belongs to the object at ffff8801c02e0280 [ 41.160966] which belongs to the cache kmalloc-16384 of size 16384 [ 41.173953] The buggy address is located 13320 bytes inside of [ 41.173953] 16384-byte region [ffff8801c02e0280, ffff8801c02e4280) [ 41.186140] The buggy address belongs to the page: [ 41.191038] page:ffffea000700b800 count:1 mapcount:0 mapping:ffff8801c02e0280 index:0x0 compound_mapcount: 0 [ 41.200980] flags: 0x200000000008100(slab|head) [ 41.205620] raw: 0200000000008100 ffff8801c02e0280 0000000000000000 0000000100000001 [ 41.213472] raw: ffffea0007020e20 ffffea0007380c20 ffff8801dac02200 0000000000000000 [ 41.221322] page dumped because: kasan: bad access detected [ 41.226997] [ 41.228593] Memory state around the buggy address: [ 41.233493] ffff8801c02e3580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 41.240820] ffff8801c02e3600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 41.248147] >ffff8801c02e3680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 41.255474] ^ [ 41.259068] ffff8801c02e3700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 41.266394] ffff8801c02e3780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 41.273717] ================================================================== [ 41.281042] Disabling lock debugging due to kernel taint [ 41.286453] Kernel panic - not syncing: panic_on_warn set ... [ 41.286453] [ 41.293777] CPU: 0 PID: 2982 Comm: syzkaller235809 Tainted: G B 4.14.0-rc2+ #20 [ 41.302312] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 41.311628] Call Trace: [ 41.314180] dump_stack+0x194/0x257 [ 41.317772] ? arch_local_irq_restore+0x53/0x53 [ 41.322502] ? vprintk_default+0x28/0x30 [ 41.326531] ? __internal_add_timer+0x180/0x2d0 [ 41.331167] panic+0x1e4/0x417 [ 41.334323] ? __warn+0x1d9/0x1d9 [ 41.337747] ? __internal_add_timer+0x275/0x2d0 [ 41.342380] kasan_end_report+0x50/0x50 [ 41.346319] kasan_report+0x144/0x340 [ 41.350086] __asan_report_store8_noabort+0x17/0x20 [ 41.355065] __internal_add_timer+0x275/0x2d0 [ 41.359527] ? calc_wheel_index+0x200/0x200 [ 41.363817] mod_timer+0x622/0x15b0 [ 41.367413] ? mod_timer_pending+0x14e0/0x14e0 [ 41.371959] ? __lock_is_held+0xbc/0x140 [ 41.375992] ? __lock_is_held+0xbc/0x140 [ 41.380016] ? __lockdep_init_map+0xe4/0x650 [ 41.384389] ? lockdep_init_map+0x3d/0x70 [ 41.388503] ? rcu_read_lock_sched_held+0x108/0x120 [ 41.393482] ? init_timer_key+0x126/0x3b0 [ 41.397595] ? try_to_del_timer_sync+0x120/0x120 [ 41.402324] ? round_jiffies_up+0xce/0x100 [ 41.406522] ? __round_jiffies_up_relative+0x150/0x150 [ 41.411762] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 41.416656] ? selinux_tun_dev_alloc_security+0x124/0x170 [ 41.422159] __tun_chr_ioctl+0x1b23/0x3d20 [ 41.426363] ? tun_chr_read_iter+0x1e0/0x1e0 [ 41.430734] ? __pmd_alloc+0x4e0/0x4e0 [ 41.434587] ? __might_sleep+0x95/0x190 [ 41.438529] ? selinux_file_ioctl+0x444/0x690 [ 41.442988] ? __fget_light+0x29d/0x390 [ 41.446928] ? selinux_capable+0x40/0x40 [ 41.450962] tun_chr_compat_ioctl+0x29/0x30 [ 41.455266] ? tun_chr_compat_ioctl+0x29/0x30 [ 41.459728] compat_SyS_ioctl+0x1d7/0x3290 [ 41.463926] ? __handle_mm_fault+0x39c0/0x39c0 [ 41.468470] ? __tun_chr_ioctl+0x3d20/0x3d20 [ 41.472843] ? do_ioctl+0x60/0x60 [ 41.476260] ? do_fast_syscall_32+0x158/0xf05 [ 41.480720] ? do_ioctl+0x60/0x60 [ 41.484145] do_fast_syscall_32+0x3f2/0xf05 [ 41.488433] ? do_int80_syscall_32+0x940/0x940 [ 41.492980] ? kasan_check_read+0x11/0x20 [ 41.497093] ? syscall_return_slowpath+0x510/0x510 [ 41.501988] ? SyS_rt_sigaction+0x94/0x1b0 [ 41.506188] ? lockdep_sys_exit+0x47/0xf0 [ 41.510299] ? retint_user+0x18/0x20 [ 41.513981] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 41.518792] entry_SYSENTER_compat+0x51/0x60 [ 41.523173] RIP: 0023:0xf7fd8c79 [ 41.526502] RSP: 002b:00000000ff9db9dc EFLAGS: 00000286 ORIG_RAX: 0000000000000036 [ 41.534171] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00000000400454ca [ 41.541407] RDX: 0000000020bc5000 RSI: 00000000080ef00c RDI: 000000000000003f [ 41.548642] RBP: 0000000000001000 R08: 0000000000000000 R09: 0000000000000000 [ 41.555878] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 41.563114] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000