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-386-4,10.128.0.31' (ECDSA) to the list of known hosts. executing program executing program syzkaller login: [ 40.824928] ================================================================== [ 40.826106] BUG: KASAN: use-after-free in __internal_add_timer+0x275/0x2d0 [ 40.827044] Write of size 8 at addr ffff8801d25bb600 by task syzkaller834940/2986 [ 40.828038] [ 40.828272] CPU: 1 PID: 2986 Comm: syzkaller834940 Not tainted 4.14.0-rc5+ #48 [ 40.829237] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 40.830455] Call Trace: [ 40.830816] dump_stack+0x194/0x257 [ 40.831324] ? arch_local_irq_restore+0x53/0x53 [ 40.831973] ? show_regs_print_info+0x65/0x65 [ 40.832577] ? __kernel_text_address+0xd/0x40 [ 40.833174] ? __internal_add_timer+0x275/0x2d0 [ 40.833799] print_address_description+0x73/0x250 [ 40.834443] ? __internal_add_timer+0x275/0x2d0 [ 40.835065] kasan_report+0x25b/0x340 [ 40.835579] __asan_report_store8_noabort+0x17/0x20 [ 40.836244] __internal_add_timer+0x275/0x2d0 [ 40.836845] ? calc_wheel_index+0x200/0x200 [ 40.837430] mod_timer+0x622/0x15b0 [ 40.837928] ? mod_timer_pending+0x14e0/0x14e0 [ 40.838555] ? __lock_is_held+0xb6/0x140 [ 40.839114] ? __lock_is_held+0xb6/0x140 [ 40.839665] ? __lockdep_init_map+0xe4/0x650 [ 40.840257] ? lockdep_init_map+0x9/0x10 [ 40.840801] ? init_timer_key+0x126/0x3b0 [ 40.841369] ? try_to_del_timer_sync+0x120/0x120 [ 40.842007] ? round_jiffies_up+0xce/0x100 [ 40.842578] ? __round_jiffies_up_relative+0x150/0x150 [ 40.843278] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 40.843969] ? selinux_tun_dev_alloc_security+0x124/0x170 [ 40.844712] __tun_chr_ioctl+0x1b17/0x3d20 [ 40.845288] ? tun_chr_read_iter+0x1e0/0x1e0 [ 40.849666] ? find_held_lock+0x35/0x1d0 [ 40.853703] ? __might_sleep+0x95/0x190 [ 40.857642] ? handle_mm_fault+0x248/0x8d0 [ 40.861850] ? selinux_file_ioctl+0x444/0x690 [ 40.866313] ? __fget_light+0x297/0x380 [ 40.870255] ? selinux_capable+0x40/0x40 [ 40.874292] ? handle_mm_fault+0x410/0x8d0 [ 40.878498] tun_chr_compat_ioctl+0x29/0x30 [ 40.882782] ? tun_chr_compat_ioctl+0x29/0x30 [ 40.887245] compat_SyS_ioctl+0x1d7/0x3290 [ 40.891448] ? up_read+0x1a/0x40 [ 40.894780] ? __tun_chr_ioctl+0x3d20/0x3d20 [ 40.899157] ? do_ioctl+0x60/0x60 [ 40.902581] ? do_fast_syscall_32+0x158/0xf05 [ 40.907044] ? do_ioctl+0x60/0x60 [ 40.910461] do_fast_syscall_32+0x3f2/0xf05 [ 40.914756] ? do_int80_syscall_32+0x940/0x940 [ 40.919305] ? kasan_check_read+0x11/0x20 [ 40.923426] ? syscall_return_slowpath+0x510/0x510 [ 40.928323] ? SyS_rt_sigaction+0x94/0x1b0 [ 40.932531] ? SyS_sigprocmask+0x4b0/0x4b0 [ 40.936734] ? SyS_read+0x184/0x220 [ 40.940333] ? retint_user+0x18/0x20 [ 40.944021] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 40.948837] entry_SYSENTER_compat+0x51/0x60 [ 40.953213] RIP: 0023:0xf7f88c79 [ 40.956542] RSP: 002b:00000000ffcc9ddc EFLAGS: 00000207 ORIG_RAX: 0000000000000036 [ 40.964215] RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 00000000400454ca [ 40.971449] RDX: 0000000020927fd8 RSI: 0000000000000037 RDI: 0000000000000005 [ 40.978685] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 40.985919] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 40.993153] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 41.000408] [ 41.002002] Allocated by task 2986: [ 41.005599] save_stack_trace+0x16/0x20 [ 41.009538] save_stack+0x43/0xd0 [ 41.012954] kasan_kmalloc+0xad/0xe0 [ 41.016633] __kmalloc_node+0x47/0x70 [ 41.020402] kvmalloc_node+0x64/0xd0 [ 41.024080] alloc_netdev_mqs+0x16e/0xed0 [ 41.028194] __tun_chr_ioctl+0x12b2/0x3d20 [ 41.032392] tun_chr_compat_ioctl+0x29/0x30 [ 41.036678] compat_SyS_ioctl+0x1d7/0x3290 [ 41.040878] do_fast_syscall_32+0x3f2/0xf05 [ 41.045166] entry_SYSENTER_compat+0x51/0x60 [ 41.049536] [ 41.051127] Freed by task 2986: [ 41.054376] save_stack_trace+0x16/0x20 [ 41.058314] save_stack+0x43/0xd0 [ 41.061731] kasan_slab_free+0x71/0xc0 [ 41.065582] kfree+0xca/0x250 [ 41.068652] kvfree+0x36/0x60 [ 41.071722] free_netdev+0x2cf/0x360 [ 41.075404] __tun_chr_ioctl+0x2cea/0x3d20 [ 41.079602] tun_chr_compat_ioctl+0x29/0x30 [ 41.083887] compat_SyS_ioctl+0x1d7/0x3290 [ 41.088088] do_fast_syscall_32+0x3f2/0xf05 [ 41.092376] entry_SYSENTER_compat+0x51/0x60 [ 41.096747] [ 41.098341] The buggy address belongs to the object at ffff8801d25b82c0 [ 41.098341] which belongs to the cache kmalloc-16384 of size 16384 [ 41.111306] The buggy address is located 13120 bytes inside of [ 41.111306] 16384-byte region [ffff8801d25b82c0, ffff8801d25bc2c0) [ 41.123488] The buggy address belongs to the page: [ 41.128380] page:ffffea0007496e00 count:1 mapcount:0 mapping:ffff8801d25b82c0 index:0x0 compound_mapcount: 0 [ 41.138313] flags: 0x200000000008100(slab|head) [ 41.142949] raw: 0200000000008100 ffff8801d25b82c0 0000000000000000 0000000100000001 [ 41.150792] raw: ffffea000766cc20 ffffea0007478220 ffff8801dac02200 0000000000000000 [ 41.158634] page dumped because: kasan: bad access detected [ 41.164303] [ 41.165896] Memory state around the buggy address: [ 41.170790] ffff8801d25bb500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 41.178201] ffff8801d25bb580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 41.185523] >ffff8801d25bb600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 41.192844] ^ [ 41.196174] ffff8801d25bb680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 41.203494] ffff8801d25bb700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 41.210813] ================================================================== [ 41.218135] Disabling lock debugging due to kernel taint [ 41.223547] Kernel panic - not syncing: panic_on_warn set ... [ 41.223547] [ 41.230874] CPU: 1 PID: 2986 Comm: syzkaller834940 Tainted: G B 4.14.0-rc5+ #48 [ 41.239410] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 41.248727] Call Trace: [ 41.251285] dump_stack+0x194/0x257 [ 41.254876] ? arch_local_irq_restore+0x53/0x53 [ 41.259508] ? kasan_end_report+0x32/0x50 [ 41.263624] ? lock_downgrade+0x990/0x990 [ 41.267743] ? __internal_add_timer+0x1c0/0x2d0 [ 41.272377] panic+0x1e4/0x417 [ 41.275549] ? __warn+0x1d9/0x1d9 [ 41.278972] ? __internal_add_timer+0x275/0x2d0 [ 41.283605] kasan_end_report+0x50/0x50 [ 41.287542] kasan_report+0x144/0x340 [ 41.291310] __asan_report_store8_noabort+0x17/0x20 [ 41.296292] __internal_add_timer+0x275/0x2d0 [ 41.300753] ? calc_wheel_index+0x200/0x200 [ 41.305045] mod_timer+0x622/0x15b0 [ 41.308640] ? mod_timer_pending+0x14e0/0x14e0 [ 41.313188] ? __lock_is_held+0xb6/0x140 [ 41.317219] ? __lock_is_held+0xb6/0x140 [ 41.321245] ? __lockdep_init_map+0xe4/0x650 [ 41.325619] ? lockdep_init_map+0x9/0x10 [ 41.329650] ? init_timer_key+0x126/0x3b0 [ 41.333762] ? try_to_del_timer_sync+0x120/0x120 [ 41.338480] ? round_jiffies_up+0xce/0x100 [ 41.342679] ? __round_jiffies_up_relative+0x150/0x150 [ 41.347920] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 41.352811] ? selinux_tun_dev_alloc_security+0x124/0x170 [ 41.358317] __tun_chr_ioctl+0x1b17/0x3d20 [ 41.362522] ? tun_chr_read_iter+0x1e0/0x1e0 [ 41.366898] ? find_held_lock+0x35/0x1d0 [ 41.370928] ? __might_sleep+0x95/0x190 [ 41.374864] ? handle_mm_fault+0x248/0x8d0 [ 41.379065] ? selinux_file_ioctl+0x444/0x690 [ 41.383526] ? __fget_light+0x297/0x380 [ 41.387465] ? selinux_capable+0x40/0x40 [ 41.391495] ? handle_mm_fault+0x410/0x8d0 [ 41.395695] tun_chr_compat_ioctl+0x29/0x30 [ 41.399981] ? tun_chr_compat_ioctl+0x29/0x30 [ 41.404442] compat_SyS_ioctl+0x1d7/0x3290 [ 41.408640] ? up_read+0x1a/0x40 [ 41.411971] ? __tun_chr_ioctl+0x3d20/0x3d20 [ 41.416343] ? do_ioctl+0x60/0x60 [ 41.419762] ? do_fast_syscall_32+0x158/0xf05 [ 41.424220] ? do_ioctl+0x60/0x60 [ 41.427636] do_fast_syscall_32+0x3f2/0xf05 [ 41.431924] ? do_int80_syscall_32+0x940/0x940 [ 41.436907] ? kasan_check_read+0x11/0x20 [ 41.441017] ? syscall_return_slowpath+0x510/0x510 [ 41.445910] ? SyS_rt_sigaction+0x94/0x1b0 [ 41.450108] ? SyS_sigprocmask+0x4b0/0x4b0 [ 41.454308] ? SyS_read+0x184/0x220 [ 41.457901] ? retint_user+0x18/0x20 [ 41.461580] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 41.466388] entry_SYSENTER_compat+0x51/0x60 [ 41.470758] RIP: 0023:0xf7f88c79 [ 41.474085] RSP: 002b:00000000ffcc9ddc EFLAGS: 00000207 ORIG_RAX: 0000000000000036 [ 41.481754] RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 00000000400454ca [ 41.488987] RDX: 0000000020927fd8 RSI: 0000000000000037 RDI: 0000000000000005 [ 41.496393] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 41.503625] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 41.510859] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000