[....] 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. [ 41.018938] audit: type=1800 audit(1569815752.455:33): pid=7588 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 Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 44.695812] kauditd_printk_skb: 1 callbacks suppressed [ 44.695826] audit: type=1400 audit(1569815756.135:35): avc: denied { map } for pid=7762 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 '10.128.0.89' (ECDSA) to the list of known hosts. executing program [ 66.058595] audit: type=1400 audit(1569815777.495:36): avc: denied { map } for pid=7774 comm="syz-executor724" path="/root/syz-executor724921585" dev="sda1" ino=16484 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 [ 66.088824] ================================================================== [ 66.096974] BUG: KASAN: use-after-free in wait_consider_task+0x1b51/0x3910 [ 66.104192] Read of size 4 at addr ffff8880a68e8b2c by task sshd/7772 [ 66.110783] [ 66.112406] CPU: 0 PID: 7772 Comm: sshd Not tainted 4.19.75 #0 [ 66.118449] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 66.127790] Call Trace: [ 66.130376] dump_stack+0x172/0x1f0 [ 66.133993] ? wait_consider_task+0x1b51/0x3910 [ 66.138664] print_address_description.cold+0x7c/0x20d [ 66.143931] ? wait_consider_task+0x1b51/0x3910 [ 66.148591] kasan_report.cold+0x8c/0x2ba [ 66.152734] __asan_report_load4_noabort+0x14/0x20 [ 66.157748] wait_consider_task+0x1b51/0x3910 [ 66.162254] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 66.167343] ? add_wait_queue+0x112/0x170 [ 66.171570] ? release_task+0x1630/0x1630 [ 66.175705] ? lock_acquire+0x16f/0x3f0 [ 66.179668] ? do_wait+0x3aa/0x9d0 [ 66.183311] ? kasan_check_write+0x14/0x20 [ 66.187561] do_wait+0x439/0x9d0 [ 66.190930] ? wait_consider_task+0x3910/0x3910 [ 66.195673] ? mark_held_locks+0x100/0x100 [ 66.200506] kernel_wait4+0x171/0x290 [ 66.204325] ? __ia32_sys_waitid+0x140/0x140 [ 66.208854] ? task_stopped_code+0x180/0x180 [ 66.213265] __do_sys_wait4+0x147/0x160 [ 66.217294] ? kernel_wait4+0x290/0x290 [ 66.221285] ? kasan_check_read+0x11/0x20 [ 66.225447] ? _copy_to_user+0xc9/0x120 [ 66.229419] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 66.235065] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 66.240377] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 66.245455] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 66.251035] ? do_syscall_64+0x26/0x620 [ 66.255112] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.261635] ? do_syscall_64+0x26/0x620 [ 66.265609] __x64_sys_wait4+0x97/0xf0 [ 66.269502] do_syscall_64+0xfd/0x620 [ 66.273296] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.278600] RIP: 0033:0x7f713eb2ba3e [ 66.282302] 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 [ 66.301297] RSP: 002b:00007ffeb67c0c10 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 66.309003] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f713eb2ba3e [ 66.316311] RDX: 0000000000000001 RSI: 00007ffeb67c0c4c RDI: ffffffffffffffff [ 66.323578] RBP: 000055aebfc9bc88 R08: 00007ffeb67c0d10 R09: 0101010101010101 [ 66.331172] R10: 0000000000000000 R11: 0000000000000246 R12: 000055aec0c50af0 [ 66.338554] R13: 000055aebfc99fb4 R14: 0000000000000028 R15: 000055aebfc9bca0 [ 66.345848] [ 66.347642] Allocated by task 7772: [ 66.351260] save_stack+0x45/0xd0 [ 66.354702] kasan_kmalloc+0xce/0xf0 [ 66.358413] kasan_slab_alloc+0xf/0x20 [ 66.362350] kmem_cache_alloc_node+0x144/0x710 [ 66.367318] copy_process.part.0+0x1ce0/0x7a30 [ 66.371911] _do_fork+0x257/0xfd0 [ 66.375360] __x64_sys_clone+0xbf/0x150 [ 66.379327] do_syscall_64+0xfd/0x620 [ 66.383132] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.388322] [ 66.389946] Freed by task 0: [ 66.392957] save_stack+0x45/0xd0 [ 66.396501] __kasan_slab_free+0x102/0x150 [ 66.400728] kasan_slab_free+0xe/0x10 [ 66.404516] kmem_cache_free+0x86/0x260 [ 66.408687] free_task+0xdd/0x120 [ 66.412136] __put_task_struct+0x20f/0x4c0 [ 66.416362] finish_task_switch+0x52b/0x780 [ 66.420909] __schedule+0x86e/0x1dc0 [ 66.424615] schedule_idle+0x58/0x80 [ 66.428320] do_idle+0x192/0x560 [ 66.431681] cpu_startup_entry+0xc8/0xe0 [ 66.435864] start_secondary+0x3e8/0x5b0 [ 66.439961] secondary_startup_64+0xa4/0xb0 [ 66.445414] [ 66.447122] The buggy address belongs to the object at ffff8880a68e86c0 [ 66.447122] which belongs to the cache task_struct of size 6080 [ 66.460646] The buggy address is located 1132 bytes inside of [ 66.460646] 6080-byte region [ffff8880a68e86c0, ffff8880a68e9e80) [ 66.473449] The buggy address belongs to the page: [ 66.478454] page:ffffea00029a3a00 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 [ 66.488605] flags: 0x1fffc0000008100(slab|head) [ 66.493264] raw: 01fffc0000008100 ffffea0002a06f08 ffffea0002a27708 ffff88812c26d800 [ 66.501221] raw: 0000000000000000 ffff8880a68e86c0 0000000100000001 0000000000000000 [ 66.509268] page dumped because: kasan: bad access detected [ 66.514959] [ 66.516579] Memory state around the buggy address: [ 66.521647] ffff8880a68e8a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 66.529968] ffff8880a68e8a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 66.537530] >ffff8880a68e8b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 66.544888] ^ [ 66.549632] ffff8880a68e8b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 66.557001] ffff8880a68e8c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 66.564530] ================================================================== [ 66.571879] Disabling lock debugging due to kernel taint [ 66.577691] Kernel panic - not syncing: panic_on_warn set ... [ 66.577691] [ 66.585329] CPU: 0 PID: 7772 Comm: sshd Tainted: G B 4.19.75 #0 [ 66.593015] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 66.602533] Call Trace: [ 66.605116] dump_stack+0x172/0x1f0 [ 66.608744] ? wait_consider_task+0x1b51/0x3910 [ 66.613556] panic+0x263/0x507 [ 66.616752] ? __warn_printk+0xf3/0xf3 [ 66.620633] ? retint_kernel+0x2d/0x2d [ 66.624522] ? trace_hardirqs_on+0x5e/0x220 [ 66.629001] ? wait_consider_task+0x1b51/0x3910 [ 66.633679] kasan_end_report+0x47/0x4f [ 66.637742] kasan_report.cold+0xa9/0x2ba [ 66.641882] __asan_report_load4_noabort+0x14/0x20 [ 66.647058] wait_consider_task+0x1b51/0x3910 [ 66.651542] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 66.656723] ? add_wait_queue+0x112/0x170 [ 66.661382] ? release_task+0x1630/0x1630 [ 66.665643] ? lock_acquire+0x16f/0x3f0 [ 66.669748] ? do_wait+0x3aa/0x9d0 [ 66.673367] ? kasan_check_write+0x14/0x20 [ 66.677691] do_wait+0x439/0x9d0 [ 66.681099] ? wait_consider_task+0x3910/0x3910 [ 66.685771] ? mark_held_locks+0x100/0x100 [ 66.690001] kernel_wait4+0x171/0x290 [ 66.693801] ? __ia32_sys_waitid+0x140/0x140 [ 66.698445] ? task_stopped_code+0x180/0x180 [ 66.702843] __do_sys_wait4+0x147/0x160 [ 66.706838] ? kernel_wait4+0x290/0x290 [ 66.710814] ? kasan_check_read+0x11/0x20 [ 66.714964] ? _copy_to_user+0xc9/0x120 [ 66.718943] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 66.724584] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 66.729690] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 66.734454] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 66.739240] ? do_syscall_64+0x26/0x620 [ 66.743289] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.748637] ? do_syscall_64+0x26/0x620 [ 66.752613] __x64_sys_wait4+0x97/0xf0 [ 66.756505] do_syscall_64+0xfd/0x620 [ 66.760307] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.765496] RIP: 0033:0x7f713eb2ba3e [ 66.769663] 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 [ 66.788850] RSP: 002b:00007ffeb67c0c10 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 66.796555] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f713eb2ba3e [ 66.804782] RDX: 0000000000000001 RSI: 00007ffeb67c0c4c RDI: ffffffffffffffff [ 66.812038] RBP: 000055aebfc9bc88 R08: 00007ffeb67c0d10 R09: 0101010101010101 [ 66.819302] R10: 0000000000000000 R11: 0000000000000246 R12: 000055aec0c50af0 [ 66.826561] R13: 000055aebfc99fb4 R14: 0000000000000028 R15: 000055aebfc9bca0 [ 66.837613] Kernel Offset: disabled [ 66.841250] Rebooting in 86400 seconds..