[....] 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. [ 37.299844] audit: type=1800 audit(1569512321.882:33): pid=7300 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 [ 37.321232] audit: type=1800 audit(1569512321.882:34): pid=7300 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: [ 41.641521] audit: type=1400 audit(1569512326.222:35): avc: denied { map } for pid=7473 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 '10.128.0.231' (ECDSA) to the list of known hosts. executing program [ 48.219634] audit: type=1400 audit(1569512332.802:36): avc: denied { map } for pid=7485 comm="syz-executor438" path="/root/syz-executor438605340" 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 [ 48.251847] ================================================================== [ 48.259993] BUG: KASAN: use-after-free in wait_consider_task+0x1b51/0x3910 [ 48.266990] Read of size 4 at addr ffff888099a205ec by task sshd/7483 [ 48.273545] [ 48.275159] CPU: 0 PID: 7483 Comm: sshd Not tainted 4.19.75 #0 [ 48.281151] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 48.290486] Call Trace: [ 48.293071] dump_stack+0x172/0x1f0 [ 48.296703] ? wait_consider_task+0x1b51/0x3910 [ 48.301359] print_address_description.cold+0x7c/0x20d [ 48.306621] ? wait_consider_task+0x1b51/0x3910 [ 48.311275] kasan_report.cold+0x8c/0x2ba [ 48.315413] __asan_report_load4_noabort+0x14/0x20 [ 48.320345] wait_consider_task+0x1b51/0x3910 [ 48.324820] ? mark_held_locks+0x100/0x100 [ 48.329058] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 48.334143] ? add_wait_queue+0x112/0x170 [ 48.338309] ? release_task+0x1630/0x1630 [ 48.342474] ? lock_acquire+0x16f/0x3f0 [ 48.346443] ? do_wait+0x3aa/0x9d0 [ 48.349971] ? kasan_check_write+0x14/0x20 [ 48.354201] do_wait+0x439/0x9d0 [ 48.357566] ? wait_consider_task+0x3910/0x3910 [ 48.362217] ? mark_held_locks+0x100/0x100 [ 48.366450] kernel_wait4+0x171/0x290 [ 48.370250] ? __ia32_sys_waitid+0x140/0x140 [ 48.374651] ? task_stopped_code+0x180/0x180 [ 48.379056] __do_sys_wait4+0x147/0x160 [ 48.383016] ? kernel_wait4+0x290/0x290 [ 48.386994] ? kasan_check_read+0x11/0x20 [ 48.391126] ? _copy_to_user+0xc9/0x120 [ 48.395088] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 48.400623] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 48.405623] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 48.410362] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 48.415098] ? do_syscall_64+0x26/0x620 [ 48.419059] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.424404] ? do_syscall_64+0x26/0x620 [ 48.428368] __x64_sys_wait4+0x97/0xf0 [ 48.432243] do_syscall_64+0xfd/0x620 [ 48.436042] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.441215] RIP: 0033:0x7f99410f4a3e [ 48.444913] 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 [ 48.464491] RSP: 002b:00007ffc5dd22dd0 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 48.472188] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f99410f4a3e [ 48.479442] RDX: 0000000000000001 RSI: 00007ffc5dd22e0c RDI: ffffffffffffffff [ 48.486695] RBP: 000055a0305e8c88 R08: 00007ffc5dd22ed0 R09: 0101010101010101 [ 48.493947] R10: 0000000000000000 R11: 0000000000000246 R12: 000055a030bbcaf0 [ 48.501214] R13: 000055a0305e6fb4 R14: 0000000000000028 R15: 000055a0305e8ca0 [ 48.508484] [ 48.510094] Allocated by task 7483: [ 48.513709] save_stack+0x45/0xd0 [ 48.517145] kasan_kmalloc+0xce/0xf0 [ 48.520839] kasan_slab_alloc+0xf/0x20 [ 48.524718] kmem_cache_alloc_node+0x144/0x710 [ 48.529284] copy_process.part.0+0x1ce0/0x7a30 [ 48.533845] _do_fork+0x257/0xfd0 [ 48.537290] __x64_sys_clone+0xbf/0x150 [ 48.541249] do_syscall_64+0xfd/0x620 [ 48.545033] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.550199] [ 48.551808] Freed by task 7483: [ 48.555072] save_stack+0x45/0xd0 [ 48.558511] __kasan_slab_free+0x102/0x150 [ 48.562729] kasan_slab_free+0xe/0x10 [ 48.566510] kmem_cache_free+0x86/0x260 [ 48.570469] free_task+0xdd/0x120 [ 48.573902] __put_task_struct+0x20f/0x4c0 [ 48.578117] finish_task_switch+0x52b/0x780 [ 48.582434] __schedule+0x86e/0x1dc0 [ 48.586131] schedule+0x92/0x1c0 [ 48.589481] schedule_hrtimeout_range_clock+0x1b1/0x380 [ 48.594827] schedule_hrtimeout_range+0x2b/0x40 [ 48.599481] poll_schedule_timeout.constprop.0+0x11a/0x200 [ 48.605101] do_select+0x12bd/0x16d0 [ 48.608812] core_sys_select+0x564/0x870 [ 48.612855] kern_select+0x15d/0x1e0 [ 48.616564] __x64_sys_select+0xbe/0x150 [ 48.620671] do_syscall_64+0xfd/0x620 [ 48.624513] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.629700] [ 48.631325] The buggy address belongs to the object at ffff888099a20180 [ 48.631325] which belongs to the cache task_struct of size 6080 [ 48.644054] The buggy address is located 1132 bytes inside of [ 48.644054] 6080-byte region [ffff888099a20180, ffff888099a21940) [ 48.656090] The buggy address belongs to the page: [ 48.661004] page:ffffea0002668800 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 [ 48.670971] flags: 0x1fffc0000008100(slab|head) [ 48.675635] raw: 01fffc0000008100 ffffea000265b208 ffffea0002151b08 ffff88812c26d800 [ 48.683512] raw: 0000000000000000 ffff888099a20180 0000000100000001 0000000000000000 [ 48.691370] page dumped because: kasan: bad access detected [ 48.697059] [ 48.698663] Memory state around the buggy address: [ 48.703572] ffff888099a20480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.710915] ffff888099a20500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.718592] >ffff888099a20580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.725931] ^ [ 48.732679] ffff888099a20600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.740029] ffff888099a20680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.747367] ================================================================== [ 48.754706] Disabling lock debugging due to kernel taint [ 48.760429] Kernel panic - not syncing: panic_on_warn set ... [ 48.760429] [ 48.767808] CPU: 0 PID: 7483 Comm: sshd Tainted: G B 4.19.75 #0 [ 48.775147] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 48.784490] Call Trace: [ 48.787070] dump_stack+0x172/0x1f0 [ 48.791679] ? wait_consider_task+0x1b51/0x3910 [ 48.796333] panic+0x263/0x507 [ 48.799514] ? __warn_printk+0xf3/0xf3 [ 48.803515] ? retint_kernel+0x2d/0x2d [ 48.807404] ? trace_hardirqs_on+0x5e/0x220 [ 48.811723] ? wait_consider_task+0x1b51/0x3910 [ 48.816383] kasan_end_report+0x47/0x4f [ 48.820346] kasan_report.cold+0xa9/0x2ba [ 48.824483] __asan_report_load4_noabort+0x14/0x20 [ 48.829441] wait_consider_task+0x1b51/0x3910 [ 48.833923] ? mark_held_locks+0x100/0x100 [ 48.838143] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 48.843232] ? add_wait_queue+0x112/0x170 [ 48.847482] ? release_task+0x1630/0x1630 [ 48.851666] ? lock_acquire+0x16f/0x3f0 [ 48.855622] ? do_wait+0x3aa/0x9d0 [ 48.859151] ? kasan_check_write+0x14/0x20 [ 48.863384] do_wait+0x439/0x9d0 [ 48.866738] ? wait_consider_task+0x3910/0x3910 [ 48.871388] ? mark_held_locks+0x100/0x100 [ 48.875607] kernel_wait4+0x171/0x290 [ 48.879394] ? __ia32_sys_waitid+0x140/0x140 [ 48.883797] ? task_stopped_code+0x180/0x180 [ 48.888207] __do_sys_wait4+0x147/0x160 [ 48.892163] ? kernel_wait4+0x290/0x290 [ 48.896133] ? kasan_check_read+0x11/0x20 [ 48.900267] ? _copy_to_user+0xc9/0x120 [ 48.904244] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 48.909768] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 48.914779] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 48.919521] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 48.924258] ? do_syscall_64+0x26/0x620 [ 48.928217] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.933562] ? do_syscall_64+0x26/0x620 [ 48.937522] __x64_sys_wait4+0x97/0xf0 [ 48.941392] do_syscall_64+0xfd/0x620 [ 48.945267] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.950439] RIP: 0033:0x7f99410f4a3e [ 48.954136] 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 [ 48.973024] RSP: 002b:00007ffc5dd22dd0 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 48.980718] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f99410f4a3e [ 48.987971] RDX: 0000000000000001 RSI: 00007ffc5dd22e0c RDI: ffffffffffffffff [ 48.995233] RBP: 000055a0305e8c88 R08: 00007ffc5dd22ed0 R09: 0101010101010101 [ 49.002484] R10: 0000000000000000 R11: 0000000000000246 R12: 000055a030bbcaf0 [ 49.009747] R13: 000055a0305e6fb4 R14: 0000000000000028 R15: 000055a0305e8ca0 [ 49.018327] Kernel Offset: disabled [ 49.021954] Rebooting in 86400 seconds..