[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. Starting mcstransd: [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [ 37.771805] audit: type=1800 audit(1569202952.145:33): pid=7264 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:kernel_t:s0 op=collect_data cause=failed(directio) comm="startpar" name="rc.local" dev="sda1" ino=2465 res=0 [ 37.793295] audit: type=1800 audit(1569202952.145:34): pid=7264 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:kernel_t:s0 op=collect_data cause=failed(directio) comm="startpar" name="rmnologin" dev="sda1" ino=2456 res=0 Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 44.279564] audit: type=1400 audit(1569202958.655:35): avc: denied { map } for pid=7438 comm="bash" path="/bin/bash" dev="sda1" ino=1457 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 Warning: Permanently added '10.128.0.119' (ECDSA) to the list of known hosts. executing program [ 50.739396] audit: type=1400 audit(1569202965.115:36): avc: denied { map } for pid=7450 comm="syz-executor702" path="/root/syz-executor702847095" dev="sda1" ino=16483 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 [ 50.769085] ================================================================== [ 50.776509] BUG: KASAN: use-after-free in wait_consider_task+0x1b51/0x3910 [ 50.783514] Read of size 4 at addr ffff888098c388ac by task sshd/7448 [ 50.790073] [ 50.791687] CPU: 0 PID: 7448 Comm: sshd Not tainted 4.19.75 #0 [ 50.797651] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 50.807076] Call Trace: [ 50.809666] dump_stack+0x172/0x1f0 [ 50.813292] ? wait_consider_task+0x1b51/0x3910 [ 50.817947] print_address_description.cold+0x7c/0x20d [ 50.823226] ? wait_consider_task+0x1b51/0x3910 [ 50.827879] kasan_report.cold+0x8c/0x2ba [ 50.832013] __asan_report_load4_noabort+0x14/0x20 [ 50.836936] wait_consider_task+0x1b51/0x3910 [ 50.841418] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 50.846503] ? add_wait_queue+0x112/0x170 [ 50.850648] ? release_task+0x1630/0x1630 [ 50.854776] ? lock_acquire+0x16f/0x3f0 [ 50.858735] ? do_wait+0x3aa/0x9d0 [ 50.862285] ? kasan_check_write+0x14/0x20 [ 50.866502] do_wait+0x439/0x9d0 [ 50.869854] ? wait_consider_task+0x3910/0x3910 [ 50.874505] ? mark_held_locks+0x100/0x100 [ 50.878736] kernel_wait4+0x171/0x290 [ 50.882533] ? __ia32_sys_waitid+0x140/0x140 [ 50.886926] ? task_stopped_code+0x180/0x180 [ 50.891321] __do_sys_wait4+0x147/0x160 [ 50.895276] ? kernel_wait4+0x290/0x290 [ 50.899235] ? kasan_check_read+0x11/0x20 [ 50.903368] ? _copy_to_user+0xc9/0x120 [ 50.907326] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 50.912847] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 50.917845] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 50.922640] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 50.927394] ? do_syscall_64+0x26/0x620 [ 50.931365] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 50.936721] ? do_syscall_64+0x26/0x620 [ 50.940687] __x64_sys_wait4+0x97/0xf0 [ 50.944561] do_syscall_64+0xfd/0x620 [ 50.948365] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 50.953556] RIP: 0033:0x7f30d8551a3e [ 50.957265] Code: 90 90 90 90 90 90 90 90 90 90 90 90 48 83 ec 28 8b 05 c2 eb 2d 00 85 c0 75 1d 45 31 d2 48 63 d2 48 63 ff b8 3d 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 55 48 83 c4 28 c3 89 54 24 08 48 89 74 24 10 [ 50.976159] RSP: 002b:00007fff0d040950 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 50.983856] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f30d8551a3e [ 50.991105] RDX: 0000000000000001 RSI: 00007fff0d04098c RDI: ffffffffffffffff [ 50.998368] RBP: 000055d13e0c7c88 R08: 00007fff0d040a50 R09: 0101010101010101 [ 51.005631] R10: 0000000000000000 R11: 0000000000000246 R12: 000055d13eb8baf0 [ 51.012882] R13: 000055d13e0c5fb4 R14: 0000000000000028 R15: 000055d13e0c7ca0 [ 51.020143] [ 51.021750] Allocated by task 7448: [ 51.025360] save_stack+0x45/0xd0 [ 51.028805] kasan_kmalloc+0xce/0xf0 [ 51.032500] kasan_slab_alloc+0xf/0x20 [ 51.036381] kmem_cache_alloc_node+0x144/0x710 [ 51.040957] copy_process.part.0+0x1ce0/0x7a30 [ 51.045537] _do_fork+0x257/0xfd0 [ 51.048977] __x64_sys_clone+0xbf/0x150 [ 51.052935] do_syscall_64+0xfd/0x620 [ 51.056721] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.061891] [ 51.063500] Freed by task 0: [ 51.066516] save_stack+0x45/0xd0 [ 51.069953] __kasan_slab_free+0x102/0x150 [ 51.074167] kasan_slab_free+0xe/0x10 [ 51.077959] kmem_cache_free+0x86/0x260 [ 51.081911] free_task+0xdd/0x120 [ 51.085364] __put_task_struct+0x20f/0x4c0 [ 51.089577] finish_task_switch+0x52b/0x780 [ 51.093899] __schedule+0x86e/0x1dc0 [ 51.097591] schedule_idle+0x58/0x80 [ 51.101283] do_idle+0x192/0x560 [ 51.104630] cpu_startup_entry+0xc8/0xe0 [ 51.108673] start_secondary+0x3e8/0x5b0 [ 51.112716] secondary_startup_64+0xa4/0xb0 [ 51.117023] [ 51.118631] The buggy address belongs to the object at ffff888098c38440 [ 51.118631] which belongs to the cache task_struct of size 6080 [ 51.131541] The buggy address is located 1132 bytes inside of [ 51.131541] 6080-byte region [ffff888098c38440, ffff888098c39c00) [ 51.143568] The buggy address belongs to the page: [ 51.148479] page:ffffea0002630e00 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 [ 51.158440] flags: 0x1fffc0000008100(slab|head) [ 51.163096] raw: 01fffc0000008100 ffffea000287cb08 ffffea0002520388 ffff88812c26d800 [ 51.170958] raw: 0000000000000000 ffff888098c38440 0000000100000001 0000000000000000 [ 51.178817] page dumped because: kasan: bad access detected [ 51.184513] [ 51.186124] Memory state around the buggy address: [ 51.191042] ffff888098c38780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 51.198383] ffff888098c38800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 51.205721] >ffff888098c38880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 51.213055] ^ [ 51.217707] ffff888098c38900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 51.225054] ffff888098c38980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 51.232390] ================================================================== [ 51.239725] Disabling lock debugging due to kernel taint [ 51.245308] Kernel panic - not syncing: panic_on_warn set ... [ 51.245308] [ 51.252682] CPU: 0 PID: 7448 Comm: sshd Tainted: G B 4.19.75 #0 [ 51.260021] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 51.269367] Call Trace: [ 51.271939] dump_stack+0x172/0x1f0 [ 51.275549] ? wait_consider_task+0x1b51/0x3910 [ 51.280197] panic+0x263/0x507 [ 51.283369] ? __warn_printk+0xf3/0xf3 [ 51.287237] ? retint_kernel+0x2d/0x2d [ 51.291110] ? trace_hardirqs_on+0x5e/0x220 [ 51.295500] ? wait_consider_task+0x1b51/0x3910 [ 51.300151] kasan_end_report+0x47/0x4f [ 51.304108] kasan_report.cold+0xa9/0x2ba [ 51.308240] __asan_report_load4_noabort+0x14/0x20 [ 51.313162] wait_consider_task+0x1b51/0x3910 [ 51.317640] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 51.322732] ? add_wait_queue+0x112/0x170 [ 51.326860] ? release_task+0x1630/0x1630 [ 51.330987] ? lock_acquire+0x16f/0x3f0 [ 51.334940] ? do_wait+0x3aa/0x9d0 [ 51.338471] ? kasan_check_write+0x14/0x20 [ 51.342686] do_wait+0x439/0x9d0 [ 51.346033] ? wait_consider_task+0x3910/0x3910 [ 51.350680] ? mark_held_locks+0x100/0x100 [ 51.354906] kernel_wait4+0x171/0x290 [ 51.358688] ? __ia32_sys_waitid+0x140/0x140 [ 51.363078] ? task_stopped_code+0x180/0x180 [ 51.367467] __do_sys_wait4+0x147/0x160 [ 51.371434] ? kernel_wait4+0x290/0x290 [ 51.375389] ? kasan_check_read+0x11/0x20 [ 51.379520] ? _copy_to_user+0xc9/0x120 [ 51.383474] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 51.389183] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 51.394191] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 51.398934] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 51.403668] ? do_syscall_64+0x26/0x620 [ 51.407632] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.412991] ? do_syscall_64+0x26/0x620 [ 51.416976] __x64_sys_wait4+0x97/0xf0 [ 51.420854] do_syscall_64+0xfd/0x620 [ 51.424642] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.429809] RIP: 0033:0x7f30d8551a3e [ 51.433504] Code: 90 90 90 90 90 90 90 90 90 90 90 90 48 83 ec 28 8b 05 c2 eb 2d 00 85 c0 75 1d 45 31 d2 48 63 d2 48 63 ff b8 3d 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 55 48 83 c4 28 c3 89 54 24 08 48 89 74 24 10 [ 51.452386] RSP: 002b:00007fff0d040950 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 51.460160] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f30d8551a3e [ 51.467408] RDX: 0000000000000001 RSI: 00007fff0d04098c RDI: ffffffffffffffff [ 51.474716] RBP: 000055d13e0c7c88 R08: 00007fff0d040a50 R09: 0101010101010101 [ 51.481968] R10: 0000000000000000 R11: 0000000000000246 R12: 000055d13eb8baf0 [ 51.489222] R13: 000055d13e0c5fb4 R14: 0000000000000028 R15: 000055d13e0c7ca0 [ 51.497730] Kernel Offset: disabled [ 51.501355] Rebooting in 86400 seconds..