INIT: Entering runlevel: 2 [info] Using makefile-style concurrent boot in runlevel 2. [....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added 'ci-upstream-kasan-gce-386-3,10.128.0.51' (ECDSA) to the list of known hosts. executing program executing program syzkaller login: [ 44.109598] ================================================================== [ 44.110736] BUG: KASAN: use-after-free in __internal_add_timer+0x275/0x2d0 [ 44.111670] Write of size 8 at addr ffff8801d1e2b600 by task syzkaller373650/2987 [ 44.112681] [ 44.112916] CPU: 1 PID: 2987 Comm: syzkaller373650 Not tainted 4.14.0-rc5+ #52 [ 44.114151] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 44.115370] Call Trace: [ 44.115727] dump_stack+0x194/0x257 [ 44.116233] ? arch_local_irq_restore+0x53/0x53 [ 44.116872] ? show_regs_print_info+0x65/0x65 [ 44.117490] ? __kernel_text_address+0xd/0x40 [ 44.118088] ? __internal_add_timer+0x275/0x2d0 [ 44.118711] print_address_description+0x73/0x250 [ 44.119356] ? __internal_add_timer+0x275/0x2d0 [ 44.119979] kasan_report+0x25b/0x340 [ 44.120493] __asan_report_store8_noabort+0x17/0x20 [ 44.121170] __internal_add_timer+0x275/0x2d0 [ 44.121772] ? calc_wheel_index+0x200/0x200 [ 44.122361] mod_timer+0x622/0x15b0 [ 44.122858] ? mod_timer_pending+0x14e0/0x14e0 [ 44.123483] ? __lock_is_held+0xb6/0x140 [ 44.124040] ? __lock_is_held+0xb6/0x140 [ 44.124592] ? __lockdep_init_map+0xe4/0x650 [ 44.125183] ? lockdep_init_map+0x9/0x10 [ 44.125744] ? init_timer_key+0x126/0x3b0 [ 44.126792] ? try_to_del_timer_sync+0x120/0x120 [ 44.127427] ? round_jiffies_up+0xce/0x100 [ 44.128041] ? __round_jiffies_up_relative+0x150/0x150 [ 44.128741] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 44.129396] ? selinux_tun_dev_alloc_security+0x124/0x170 [ 44.130136] __tun_chr_ioctl+0x1b17/0x3d20 [ 44.134351] ? tun_chr_read_iter+0x1e0/0x1e0 [ 44.138728] ? find_held_lock+0x35/0x1d0 [ 44.142764] ? __might_sleep+0x95/0x190 [ 44.146703] ? handle_mm_fault+0x248/0x8d0 [ 44.150911] ? selinux_file_ioctl+0x444/0x690 [ 44.155374] ? __fget_light+0x297/0x380 [ 44.159317] ? selinux_capable+0x40/0x40 [ 44.163361] ? handle_mm_fault+0x410/0x8d0 [ 44.167575] tun_chr_compat_ioctl+0x29/0x30 [ 44.171862] ? tun_chr_compat_ioctl+0x29/0x30 [ 44.176328] compat_SyS_ioctl+0x1d7/0x3290 [ 44.180530] ? up_read+0x1a/0x40 [ 44.183861] ? __tun_chr_ioctl+0x3d20/0x3d20 [ 44.188238] ? do_ioctl+0x60/0x60 [ 44.191658] ? do_fast_syscall_32+0x158/0xf05 [ 44.196121] ? do_ioctl+0x60/0x60 [ 44.199543] do_fast_syscall_32+0x3f2/0xf05 [ 44.203835] ? do_int80_syscall_32+0x940/0x940 [ 44.208384] ? kasan_check_read+0x11/0x20 [ 44.212501] ? syscall_return_slowpath+0x510/0x510 [ 44.217397] ? SyS_rt_sigaction+0x94/0x1b0 [ 44.221603] ? SyS_sigprocmask+0x4b0/0x4b0 [ 44.225805] ? SyS_read+0x184/0x220 [ 44.229396] ? retint_user+0x18/0x20 [ 44.233080] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 44.237896] entry_SYSENTER_compat+0x51/0x60 [ 44.242268] RIP: 0023:0xf7f37c79 [ 44.246205] RSP: 002b:00000000ffa3a57c EFLAGS: 00000286 ORIG_RAX: 0000000000000036 [ 44.253879] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00000000400454ca [ 44.261114] RDX: 0000000020a5afd8 RSI: 00000000080ef00c RDI: 000000000000003f [ 44.268350] RBP: 0000000000001000 R08: 0000000000000000 R09: 0000000000000000 [ 44.275585] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 44.282821] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 44.290074] [ 44.291671] Allocated by task 2987: [ 44.295268] save_stack_trace+0x16/0x20 [ 44.299208] save_stack+0x43/0xd0 [ 44.302625] kasan_kmalloc+0xad/0xe0 [ 44.306304] __kmalloc_node+0x47/0x70 [ 44.310070] kvmalloc_node+0x64/0xd0 [ 44.313751] alloc_netdev_mqs+0x16e/0xed0 [ 44.317862] __tun_chr_ioctl+0x12b2/0x3d20 [ 44.322062] tun_chr_compat_ioctl+0x29/0x30 [ 44.326347] compat_SyS_ioctl+0x1d7/0x3290 [ 44.330548] do_fast_syscall_32+0x3f2/0xf05 [ 44.334837] entry_SYSENTER_compat+0x51/0x60 [ 44.339211] [ 44.340803] Freed by task 2987: [ 44.344046] save_stack_trace+0x16/0x20 [ 44.347985] save_stack+0x43/0xd0 [ 44.351400] kasan_slab_free+0x71/0xc0 [ 44.355252] kfree+0xca/0x250 [ 44.358322] kvfree+0x36/0x60 [ 44.361399] free_netdev+0x2cf/0x360 [ 44.365079] __tun_chr_ioctl+0x2cea/0x3d20 [ 44.369277] tun_chr_compat_ioctl+0x29/0x30 [ 44.373562] compat_SyS_ioctl+0x1d7/0x3290 [ 44.377762] do_fast_syscall_32+0x3f2/0xf05 [ 44.382049] entry_SYSENTER_compat+0x51/0x60 [ 44.386419] [ 44.388015] The buggy address belongs to the object at ffff8801d1e282c0 [ 44.388015] which belongs to the cache kmalloc-16384 of size 16384 [ 44.400983] The buggy address is located 13120 bytes inside of [ 44.400983] 16384-byte region [ffff8801d1e282c0, ffff8801d1e2c2c0) [ 44.413165] The buggy address belongs to the page: [ 44.418060] page:ffffea0007478a00 count:1 mapcount:0 mapping:ffff8801d1e282c0 index:0x0 compound_mapcount: 0 [ 44.427992] flags: 0x200000000008100(slab|head) [ 44.432627] raw: 0200000000008100 ffff8801d1e282c0 0000000000000000 0000000100000001 [ 44.440472] raw: ffffea0007652e20 ffffea0007499a20 ffff8801dac02200 0000000000000000 [ 44.448332] page dumped because: kasan: bad access detected [ 44.454003] [ 44.455595] Memory state around the buggy address: [ 44.460488] ffff8801d1e2b500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 44.467811] ffff8801d1e2b580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 44.475134] >ffff8801d1e2b600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 44.482453] ^ [ 44.485782] ffff8801d1e2b680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 44.493103] ffff8801d1e2b700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 44.500422] ================================================================== [ 44.507741] Disabling lock debugging due to kernel taint [ 44.513152] Kernel panic - not syncing: panic_on_warn set ... [ 44.513152] [ 44.520476] CPU: 1 PID: 2987 Comm: syzkaller373650 Tainted: G B 4.14.0-rc5+ #52 [ 44.529012] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 44.538329] Call Trace: [ 44.540881] dump_stack+0x194/0x257 [ 44.544474] ? arch_local_irq_restore+0x53/0x53 [ 44.549103] ? kasan_end_report+0x32/0x50 [ 44.553215] ? lock_downgrade+0x990/0x990 [ 44.557331] ? __internal_add_timer+0x1f0/0x2d0 [ 44.561965] panic+0x1e4/0x417 [ 44.565121] ? __warn+0x1d9/0x1d9 [ 44.568545] ? __internal_add_timer+0x275/0x2d0 [ 44.573175] kasan_end_report+0x50/0x50 [ 44.577111] kasan_report+0x144/0x340 [ 44.580876] __asan_report_store8_noabort+0x17/0x20 [ 44.585855] __internal_add_timer+0x275/0x2d0 [ 44.590314] ? calc_wheel_index+0x200/0x200 [ 44.594609] mod_timer+0x622/0x15b0 [ 44.598204] ? mod_timer_pending+0x14e0/0x14e0 [ 44.602749] ? __lock_is_held+0xb6/0x140 [ 44.606780] ? __lock_is_held+0xb6/0x140 [ 44.610807] ? __lockdep_init_map+0xe4/0x650 [ 44.615181] ? lockdep_init_map+0x9/0x10 [ 44.619205] ? init_timer_key+0x126/0x3b0 [ 44.623320] ? try_to_del_timer_sync+0x120/0x120 [ 44.628039] ? round_jiffies_up+0xce/0x100 [ 44.632236] ? __round_jiffies_up_relative+0x150/0x150 [ 44.637477] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 44.642372] ? selinux_tun_dev_alloc_security+0x124/0x170 [ 44.647876] __tun_chr_ioctl+0x1b17/0x3d20 [ 44.652077] ? tun_chr_read_iter+0x1e0/0x1e0 [ 44.656449] ? find_held_lock+0x35/0x1d0 [ 44.660479] ? __might_sleep+0x95/0x190 [ 44.664414] ? handle_mm_fault+0x248/0x8d0 [ 44.668616] ? selinux_file_ioctl+0x444/0x690 [ 44.673075] ? __fget_light+0x297/0x380 [ 44.677014] ? selinux_capable+0x40/0x40 [ 44.681043] ? handle_mm_fault+0x410/0x8d0 [ 44.685244] tun_chr_compat_ioctl+0x29/0x30 [ 44.689529] ? tun_chr_compat_ioctl+0x29/0x30 [ 44.693989] compat_SyS_ioctl+0x1d7/0x3290 [ 44.698187] ? up_read+0x1a/0x40 [ 44.701516] ? __tun_chr_ioctl+0x3d20/0x3d20 [ 44.705887] ? do_ioctl+0x60/0x60 [ 44.709305] ? do_fast_syscall_32+0x158/0xf05 [ 44.713769] ? do_ioctl+0x60/0x60 [ 44.717187] do_fast_syscall_32+0x3f2/0xf05 [ 44.721473] ? do_int80_syscall_32+0x940/0x940 [ 44.726021] ? kasan_check_read+0x11/0x20 [ 44.730133] ? syscall_return_slowpath+0x510/0x510 [ 44.735027] ? SyS_rt_sigaction+0x94/0x1b0 [ 44.739224] ? SyS_sigprocmask+0x4b0/0x4b0 [ 44.743424] ? SyS_read+0x184/0x220 [ 44.747013] ? retint_user+0x18/0x20 [ 44.750693] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 44.755506] entry_SYSENTER_compat+0x51/0x60 [ 44.759880] RIP: 0023:0xf7f37c79 [ 44.763208] RSP: 002b:00000000ffa3a57c EFLAGS: 00000286 ORIG_RAX: 0000000000000036 [ 44.770881] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00000000400454ca [ 44.778117] RDX: 0000000020a5afd8 RSI: 00000000080ef00c RDI: 000000000000003f [ 44.785353] RBP: 0000000000001000 R08: 0000000000000000 R09: 0000000000000000 [ 44.792586] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 44.799820] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000