[....] 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. [ 38.423119] audit: type=1800 audit(1569061153.073:33): pid=7312 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 [ 38.447904] audit: type=1800 audit(1569061153.083:34): pid=7312 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: [ 41.005196] audit: type=1400 audit(1569061155.663:35): avc: denied { map } for pid=7485 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 '10.128.10.16' (ECDSA) to the list of known hosts. executing program [ 47.497601] audit: type=1400 audit(1569061162.153:36): avc: denied { map } for pid=7498 comm="syz-executor344" path="/root/syz-executor344862382" 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 [ 47.527052] ================================================================== [ 47.534612] BUG: KASAN: use-after-free in wait_consider_task+0x1b51/0x3910 [ 47.541611] Read of size 4 at addr ffff88809729a5ec by task sshd/7496 [ 47.548169] [ 47.549784] CPU: 0 PID: 7496 Comm: sshd Not tainted 4.19.75 #0 [ 47.555831] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 47.565167] Call Trace: [ 47.567766] dump_stack+0x172/0x1f0 [ 47.571380] ? wait_consider_task+0x1b51/0x3910 [ 47.576050] print_address_description.cold+0x7c/0x20d [ 47.581342] ? wait_consider_task+0x1b51/0x3910 [ 47.586005] kasan_report.cold+0x8c/0x2ba [ 47.590274] __asan_report_load4_noabort+0x14/0x20 [ 47.595204] wait_consider_task+0x1b51/0x3910 [ 47.599715] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 47.604844] ? add_wait_queue+0x112/0x170 [ 47.608983] ? release_task+0x1630/0x1630 [ 47.613111] ? lock_acquire+0x16f/0x3f0 [ 47.617067] ? do_wait+0x3aa/0x9d0 [ 47.620595] ? kasan_check_write+0x14/0x20 [ 47.624929] do_wait+0x439/0x9d0 [ 47.628293] ? wait_consider_task+0x3910/0x3910 [ 47.632958] ? mark_held_locks+0x100/0x100 [ 47.637184] kernel_wait4+0x171/0x290 [ 47.640970] ? __ia32_sys_waitid+0x140/0x140 [ 47.645363] ? task_stopped_code+0x180/0x180 [ 47.649760] __do_sys_wait4+0x147/0x160 [ 47.653732] ? kernel_wait4+0x290/0x290 [ 47.657694] ? kasan_check_read+0x11/0x20 [ 47.661827] ? _copy_to_user+0xc9/0x120 [ 47.665789] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 47.671322] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 47.676334] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 47.681075] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 47.685836] ? do_syscall_64+0x26/0x620 [ 47.689803] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 47.695253] ? do_syscall_64+0x26/0x620 [ 47.699211] __x64_sys_wait4+0x97/0xf0 [ 47.703093] do_syscall_64+0xfd/0x620 [ 47.706887] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 47.712059] RIP: 0033:0x7fbf3cb08a3e [ 47.715781] 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 [ 47.734666] RSP: 002b:00007ffd542ae460 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 47.742359] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fbf3cb08a3e [ 47.749609] RDX: 0000000000000001 RSI: 00007ffd542ae49c RDI: ffffffffffffffff [ 47.756862] RBP: 000055a116223c88 R08: 00007ffd542ae560 R09: 0101010101010101 [ 47.764114] R10: 0000000000000000 R11: 0000000000000246 R12: 000055a1166bb9b0 [ 47.771365] R13: 000055a116221fb4 R14: 0000000000000028 R15: 000055a116223ca0 [ 47.778631] [ 47.780240] Allocated by task 7496: [ 47.783854] save_stack+0x45/0xd0 [ 47.787292] kasan_kmalloc+0xce/0xf0 [ 47.791209] kasan_slab_alloc+0xf/0x20 [ 47.795089] kmem_cache_alloc_node+0x144/0x710 [ 47.799655] copy_process.part.0+0x1ce0/0x7a30 [ 47.804223] _do_fork+0x257/0xfd0 [ 47.807657] __x64_sys_clone+0xbf/0x150 [ 47.811622] do_syscall_64+0xfd/0x620 [ 47.815414] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 47.820588] [ 47.822197] Freed by task 0: [ 47.825219] save_stack+0x45/0xd0 [ 47.828663] __kasan_slab_free+0x102/0x150 [ 47.832877] kasan_slab_free+0xe/0x10 [ 47.836660] kmem_cache_free+0x86/0x260 [ 47.840613] free_task+0xdd/0x120 [ 47.844055] __put_task_struct+0x20f/0x4c0 [ 47.848277] finish_task_switch+0x52b/0x780 [ 47.852587] __schedule+0x86e/0x1dc0 [ 47.856281] schedule_idle+0x58/0x80 [ 47.859975] do_idle+0x192/0x560 [ 47.863322] cpu_startup_entry+0xc8/0xe0 [ 47.867364] start_secondary+0x3e8/0x5b0 [ 47.871418] secondary_startup_64+0xa4/0xb0 [ 47.875717] [ 47.877336] The buggy address belongs to the object at ffff88809729a180 [ 47.877336] which belongs to the cache task_struct of size 6080 [ 47.890061] The buggy address is located 1132 bytes inside of [ 47.890061] 6080-byte region [ffff88809729a180, ffff88809729b940) [ 47.902088] The buggy address belongs to the page: [ 47.907001] page:ffffea00025ca680 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 [ 47.916962] flags: 0x1fffc0000008100(slab|head) [ 47.921624] raw: 01fffc0000008100 ffffea0002558088 ffffea00025d0388 ffff88812c26d800 [ 47.929492] raw: 0000000000000000 ffff88809729a180 0000000100000001 0000000000000000 [ 47.937351] page dumped because: kasan: bad access detected [ 47.943037] [ 47.944646] Memory state around the buggy address: [ 47.949555] ffff88809729a480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.956893] ffff88809729a500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.964232] >ffff88809729a580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.971584] ^ [ 47.978319] ffff88809729a600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.985669] ffff88809729a680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.993021] ================================================================== [ 48.000356] Disabling lock debugging due to kernel taint [ 48.005885] Kernel panic - not syncing: panic_on_warn set ... [ 48.005885] [ 48.013338] CPU: 0 PID: 7496 Comm: sshd Tainted: G B 4.19.75 #0 [ 48.020682] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 48.030018] Call Trace: [ 48.032609] dump_stack+0x172/0x1f0 [ 48.036220] ? wait_consider_task+0x1b51/0x3910 [ 48.040877] panic+0x263/0x507 [ 48.044051] ? __warn_printk+0xf3/0xf3 [ 48.047926] ? retint_kernel+0x2d/0x2d [ 48.051814] ? trace_hardirqs_on+0x5e/0x220 [ 48.056122] ? wait_consider_task+0x1b51/0x3910 [ 48.060770] kasan_end_report+0x47/0x4f [ 48.064770] kasan_report.cold+0xa9/0x2ba [ 48.068903] __asan_report_load4_noabort+0x14/0x20 [ 48.073824] wait_consider_task+0x1b51/0x3910 [ 48.078314] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 48.083397] ? add_wait_queue+0x112/0x170 [ 48.087525] ? release_task+0x1630/0x1630 [ 48.091653] ? lock_acquire+0x16f/0x3f0 [ 48.095607] ? do_wait+0x3aa/0x9d0 [ 48.099131] ? kasan_check_write+0x14/0x20 [ 48.103355] do_wait+0x439/0x9d0 [ 48.106703] ? wait_consider_task+0x3910/0x3910 [ 48.111360] ? mark_held_locks+0x100/0x100 [ 48.115583] kernel_wait4+0x171/0x290 [ 48.119368] ? __ia32_sys_waitid+0x140/0x140 [ 48.123762] ? task_stopped_code+0x180/0x180 [ 48.128154] __do_sys_wait4+0x147/0x160 [ 48.132111] ? kernel_wait4+0x290/0x290 [ 48.136069] ? kasan_check_read+0x11/0x20 [ 48.140210] ? _copy_to_user+0xc9/0x120 [ 48.144176] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 48.149694] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 48.154701] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 48.159439] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 48.164174] ? do_syscall_64+0x26/0x620 [ 48.169690] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.175042] ? do_syscall_64+0x26/0x620 [ 48.179000] __x64_sys_wait4+0x97/0xf0 [ 48.182868] do_syscall_64+0xfd/0x620 [ 48.186653] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.191821] RIP: 0033:0x7fbf3cb08a3e [ 48.195533] 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 [ 48.214424] RSP: 002b:00007ffd542ae460 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 48.222114] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fbf3cb08a3e [ 48.229367] RDX: 0000000000000001 RSI: 00007ffd542ae49c RDI: ffffffffffffffff [ 48.236617] RBP: 000055a116223c88 R08: 00007ffd542ae560 R09: 0101010101010101 [ 48.243866] R10: 0000000000000000 R11: 0000000000000246 R12: 000055a1166bb9b0 [ 48.251118] R13: 000055a116221fb4 R14: 0000000000000028 R15: 000055a116223ca0 [ 48.259818] Kernel Offset: disabled [ 48.263456] Rebooting in 86400 seconds..