[....] Starting periodic command[ 37.532929] audit: type=1800 audit(1569594506.475:32): pid=7385 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:kernel_t:s0 op=collect_data cause=failed(directio) comm="startpar" name="ssh" dev="sda1" ino=2450 res=0 scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [ 38.208811] audit: type=1800 audit(1569594507.145:33): pid=7385 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 [ 38.232675] audit: type=1800 audit(1569594507.155:34): pid=7385 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: [ 41.566927] audit: type=1400 audit(1569594510.505:35): avc: denied { map } for pid=7560 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 '10.128.0.127' (ECDSA) to the list of known hosts. executing program [ 48.100589] audit: type=1400 audit(1569594517.035:36): avc: denied { map } for pid=7572 comm="syz-executor689" path="/root/syz-executor689254866" 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 [ 48.141569] ================================================================== [ 48.149045] BUG: KASAN: use-after-free in wait_consider_task+0x1b51/0x3910 [ 48.156215] Read of size 4 at addr ffff8880a54d462c by task sshd/7570 [ 48.162777] [ 48.164393] CPU: 0 PID: 7570 Comm: sshd Not tainted 4.19.75 #0 [ 48.170348] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 48.179705] Call Trace: [ 48.182310] dump_stack+0x172/0x1f0 [ 48.185930] ? wait_consider_task+0x1b51/0x3910 [ 48.190585] print_address_description.cold+0x7c/0x20d [ 48.195849] ? wait_consider_task+0x1b51/0x3910 [ 48.200503] kasan_report.cold+0x8c/0x2ba [ 48.204644] __asan_report_load4_noabort+0x14/0x20 [ 48.209559] wait_consider_task+0x1b51/0x3910 [ 48.214043] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 48.219127] ? add_wait_queue+0x112/0x170 [ 48.223266] ? release_task+0x1630/0x1630 [ 48.227420] ? lock_acquire+0x16f/0x3f0 [ 48.231374] ? do_wait+0x3aa/0x9d0 [ 48.234905] ? kasan_check_write+0x14/0x20 [ 48.239126] do_wait+0x439/0x9d0 [ 48.242501] ? wait_consider_task+0x3910/0x3910 [ 48.247154] ? mark_held_locks+0x100/0x100 [ 48.251395] kernel_wait4+0x171/0x290 [ 48.255200] ? __ia32_sys_waitid+0x140/0x140 [ 48.259613] ? task_stopped_code+0x180/0x180 [ 48.264034] __do_sys_wait4+0x147/0x160 [ 48.268006] ? kernel_wait4+0x290/0x290 [ 48.271985] ? kasan_check_read+0x11/0x20 [ 48.276130] ? _copy_to_user+0xc9/0x120 [ 48.280102] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 48.285753] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 48.290779] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 48.295526] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 48.300265] ? do_syscall_64+0x26/0x620 [ 48.304231] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.309577] ? do_syscall_64+0x26/0x620 [ 48.313591] __x64_sys_wait4+0x97/0xf0 [ 48.317468] do_syscall_64+0xfd/0x620 [ 48.321256] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.326455] RIP: 0033:0x7f29a34e0a3e [ 48.330160] 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 [ 48.349169] RSP: 002b:00007ffe2d8cb040 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 48.356869] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f29a34e0a3e [ 48.364138] RDX: 0000000000000001 RSI: 00007ffe2d8cb07c RDI: ffffffffffffffff [ 48.371577] RBP: 000055c3c62f4c88 R08: 00007ffe2d8cb140 R09: 0101010101010101 [ 48.378948] R10: 0000000000000000 R11: 0000000000000246 R12: 000055c3c7b2cc00 [ 48.386219] R13: 000055c3c62f2fb4 R14: 0000000000000028 R15: 000055c3c62f4ca0 [ 48.394038] [ 48.395654] Allocated by task 7570: [ 48.399431] save_stack+0x45/0xd0 [ 48.402883] kasan_kmalloc+0xce/0xf0 [ 48.406630] kasan_slab_alloc+0xf/0x20 [ 48.410596] kmem_cache_alloc_node+0x144/0x710 [ 48.415178] copy_process.part.0+0x1ce0/0x7a30 [ 48.419746] _do_fork+0x257/0xfd0 [ 48.423186] __x64_sys_clone+0xbf/0x150 [ 48.427166] do_syscall_64+0xfd/0x620 [ 48.430976] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.436281] [ 48.437905] Freed by task 0: [ 48.440931] save_stack+0x45/0xd0 [ 48.444383] __kasan_slab_free+0x102/0x150 [ 48.448624] kasan_slab_free+0xe/0x10 [ 48.452414] kmem_cache_free+0x86/0x260 [ 48.456437] free_task+0xdd/0x120 [ 48.459907] __put_task_struct+0x20f/0x4c0 [ 48.464141] finish_task_switch+0x52b/0x780 [ 48.468455] __schedule+0x86e/0x1dc0 [ 48.472157] schedule_idle+0x58/0x80 [ 48.475853] do_idle+0x192/0x560 [ 48.479203] cpu_startup_entry+0xc8/0xe0 [ 48.483249] start_secondary+0x3e8/0x5b0 [ 48.487294] secondary_startup_64+0xa4/0xb0 [ 48.491591] [ 48.493203] The buggy address belongs to the object at ffff8880a54d41c0 [ 48.493203] which belongs to the cache task_struct of size 6080 [ 48.505946] The buggy address is located 1132 bytes inside of [ 48.505946] 6080-byte region [ffff8880a54d41c0, ffff8880a54d5980) [ 48.518652] The buggy address belongs to the page: [ 48.523591] page:ffffea0002953500 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 [ 48.533553] flags: 0x1fffc0000008100(slab|head) [ 48.538227] raw: 01fffc0000008100 ffffea0002220a08 ffffea0002074d08 ffff88812c26d800 [ 48.546118] raw: 0000000000000000 ffff8880a54d41c0 0000000100000001 0000000000000000 [ 48.553992] page dumped because: kasan: bad access detected [ 48.559691] [ 48.561301] Memory state around the buggy address: [ 48.566226] ffff8880a54d4500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.573579] ffff8880a54d4580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.580920] >ffff8880a54d4600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.588262] ^ [ 48.592975] ffff8880a54d4680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.600317] ffff8880a54d4700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.607935] ================================================================== [ 48.615460] Disabling lock debugging due to kernel taint [ 48.621006] Kernel panic - not syncing: panic_on_warn set ... [ 48.621006] [ 48.628391] CPU: 0 PID: 7570 Comm: sshd Tainted: G B 4.19.75 #0 [ 48.635743] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 48.645184] Call Trace: [ 48.647943] dump_stack+0x172/0x1f0 [ 48.651569] ? wait_consider_task+0x1b51/0x3910 [ 48.656221] panic+0x263/0x507 [ 48.659405] ? __warn_printk+0xf3/0xf3 [ 48.663300] ? retint_kernel+0x2d/0x2d [ 48.667173] ? trace_hardirqs_on+0x5e/0x220 [ 48.671476] ? wait_consider_task+0x1b51/0x3910 [ 48.676145] kasan_end_report+0x47/0x4f [ 48.680102] kasan_report.cold+0xa9/0x2ba [ 48.684236] __asan_report_load4_noabort+0x14/0x20 [ 48.689148] wait_consider_task+0x1b51/0x3910 [ 48.693633] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 48.699682] ? add_wait_queue+0x112/0x170 [ 48.704056] ? release_task+0x1630/0x1630 [ 48.708194] ? lock_acquire+0x16f/0x3f0 [ 48.712158] ? do_wait+0x3aa/0x9d0 [ 48.715720] ? kasan_check_write+0x14/0x20 [ 48.719965] do_wait+0x439/0x9d0 [ 48.723323] ? wait_consider_task+0x3910/0x3910 [ 48.727981] ? mark_held_locks+0x100/0x100 [ 48.732307] kernel_wait4+0x171/0x290 [ 48.736119] ? __ia32_sys_waitid+0x140/0x140 [ 48.740523] ? task_stopped_code+0x180/0x180 [ 48.744986] __do_sys_wait4+0x147/0x160 [ 48.749063] ? kernel_wait4+0x290/0x290 [ 48.753055] ? kasan_check_read+0x11/0x20 [ 48.757388] ? _copy_to_user+0xc9/0x120 [ 48.761415] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 48.766953] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 48.771963] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 48.776709] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 48.781453] ? do_syscall_64+0x26/0x620 [ 48.785426] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.790812] ? do_syscall_64+0x26/0x620 [ 48.795210] __x64_sys_wait4+0x97/0xf0 [ 48.799083] do_syscall_64+0xfd/0x620 [ 48.802902] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.808074] RIP: 0033:0x7f29a34e0a3e [ 48.811783] 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 [ 48.830682] RSP: 002b:00007ffe2d8cb040 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 48.838375] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f29a34e0a3e [ 48.845638] RDX: 0000000000000001 RSI: 00007ffe2d8cb07c RDI: ffffffffffffffff [ 48.852919] RBP: 000055c3c62f4c88 R08: 00007ffe2d8cb140 R09: 0101010101010101 [ 48.860181] R10: 0000000000000000 R11: 0000000000000246 R12: 000055c3c7b2cc00 [ 48.867524] R13: 000055c3c62f2fb4 R14: 0000000000000028 R15: 000055c3c62f4ca0 [ 48.876356] Kernel Offset: disabled [ 48.880247] Rebooting in 86400 seconds..