[....] Starting periodic command 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. [ 39.634329] audit: type=1800 audit(1569270412.354:33): pid=7448 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 [ 39.661563] audit: type=1800 audit(1569270412.354:34): pid=7448 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 [ 40.828305] audit: type=1400 audit(1569270413.554:35): avc: denied { map } for pid=7620 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 Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.15.195' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 64.798504] audit: type=1400 audit(1569270437.524:36): avc: denied { map } for pid=7633 comm="syz-executor164" path="/root/syz-executor164824359" 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 [ 64.833370] ================================================================== [ 64.840813] BUG: KASAN: use-after-free in wait_consider_task+0x1b51/0x3910 [ 64.847810] Read of size 4 at addr ffff888075bca7ac by task syz-executor164/7633 [ 64.855322] [ 64.856936] CPU: 1 PID: 7633 Comm: syz-executor164 Not tainted 4.19.75 #0 [ 64.863932] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 64.873274] Call Trace: [ 64.875863] dump_stack+0x172/0x1f0 [ 64.879480] ? wait_consider_task+0x1b51/0x3910 [ 64.884145] print_address_description.cold+0x7c/0x20d [ 64.889424] ? wait_consider_task+0x1b51/0x3910 [ 64.894074] kasan_report.cold+0x8c/0x2ba [ 64.898295] __asan_report_load4_noabort+0x14/0x20 [ 64.903204] wait_consider_task+0x1b51/0x3910 [ 64.907682] ? lockdep_hardirqs_on+0x415/0x5d0 [ 64.912249] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 64.917331] ? add_wait_queue+0x112/0x170 [ 64.921463] ? release_task+0x1630/0x1630 [ 64.925597] ? lock_acquire+0x16f/0x3f0 [ 64.929554] ? do_wait+0x3aa/0x9d0 [ 64.933086] ? kasan_check_write+0x14/0x20 [ 64.937307] do_wait+0x439/0x9d0 [ 64.940662] ? wait_consider_task+0x3910/0x3910 [ 64.945320] kernel_wait4+0x171/0x290 [ 64.949119] ? __ia32_sys_waitid+0x140/0x140 [ 64.953510] ? task_stopped_code+0x180/0x180 [ 64.957905] __do_sys_wait4+0x147/0x160 [ 64.961861] ? kernel_wait4+0x290/0x290 [ 64.965816] ? _copy_to_user+0xc9/0x120 [ 64.969773] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 64.975292] ? put_timespec64+0xda/0x140 [ 64.979342] ? nsecs_to_jiffies+0x30/0x30 [ 64.983489] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 64.988230] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 64.992987] ? do_syscall_64+0x26/0x620 [ 64.996955] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 65.002298] ? do_syscall_64+0x26/0x620 [ 65.006361] __x64_sys_wait4+0x97/0xf0 [ 65.010251] do_syscall_64+0xfd/0x620 [ 65.014048] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 65.019227] RIP: 0033:0x4013ba [ 65.022412] Code: c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 8b 05 3e 23 2d 00 85 c0 75 36 45 31 d2 48 63 d2 48 63 ff b8 3d 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 06 c3 0f 1f 44 00 00 48 c7 c2 d0 ff ff ff f7 [ 65.041295] RSP: 002b:00007ffc8948fa38 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 65.048986] RAX: ffffffffffffffda RBX: 0000000000001dd2 RCX: 00000000004013ba [ 65.056257] RDX: 0000000040000001 RSI: 00007ffc8948fa44 RDI: ffffffffffffffff [ 65.063510] RBP: 000000000000fd19 R08: 0000000000000000 R09: 0000555556a8e880 [ 65.070773] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402370 [ 65.078068] R13: 0000000000402400 R14: 0000000000000000 R15: 0000000000000000 [ 65.085344] [ 65.086962] Allocated by task 7633: [ 65.090576] save_stack+0x45/0xd0 [ 65.094009] kasan_kmalloc+0xce/0xf0 [ 65.097703] kasan_slab_alloc+0xf/0x20 [ 65.101572] kmem_cache_alloc_node+0x144/0x710 [ 65.106136] copy_process.part.0+0x1ce0/0x7a30 [ 65.110705] _do_fork+0x257/0xfd0 [ 65.114141] __x64_sys_clone+0xbf/0x150 [ 65.118107] do_syscall_64+0xfd/0x620 [ 65.121890] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 65.127052] [ 65.128658] Freed by task 0: [ 65.131657] save_stack+0x45/0xd0 [ 65.135093] __kasan_slab_free+0x102/0x150 [ 65.139317] kasan_slab_free+0xe/0x10 [ 65.143106] kmem_cache_free+0x86/0x260 [ 65.147070] free_task+0xdd/0x120 [ 65.150504] __put_task_struct+0x20f/0x4c0 [ 65.154902] finish_task_switch+0x52b/0x780 [ 65.159210] __schedule+0x86e/0x1dc0 [ 65.162903] schedule_idle+0x58/0x80 [ 65.166597] do_idle+0x192/0x560 [ 65.169949] cpu_startup_entry+0xc8/0xe0 [ 65.173988] rest_init+0x219/0x222 [ 65.177510] start_kernel+0x88c/0x8c5 [ 65.181290] x86_64_start_reservations+0x29/0x2b [ 65.186027] x86_64_start_kernel+0x77/0x7b [ 65.190262] secondary_startup_64+0xa4/0xb0 [ 65.194556] [ 65.196167] The buggy address belongs to the object at ffff888075bca340 [ 65.196167] which belongs to the cache task_struct of size 6080 [ 65.208893] The buggy address is located 1132 bytes inside of [ 65.208893] 6080-byte region [ffff888075bca340, ffff888075bcbb00) [ 65.220918] The buggy address belongs to the page: [ 65.225828] page:ffffea0001d6f280 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 [ 65.235777] flags: 0x1fffc0000008100(slab|head) [ 65.240431] raw: 01fffc0000008100 ffffea00023a3288 ffffea0001cc3988 ffff88812c26d800 [ 65.248309] raw: 0000000000000000 ffff888075bca340 0000000100000001 0000000000000000 [ 65.256166] page dumped because: kasan: bad access detected [ 65.261850] [ 65.263454] Memory state around the buggy address: [ 65.268363] ffff888075bca680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 65.275701] ffff888075bca700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 65.283040] >ffff888075bca780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 65.290385] ^ [ 65.295034] ffff888075bca800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 65.302373] ffff888075bca880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 65.309718] ================================================================== [ 65.317053] Disabling lock debugging due to kernel taint [ 65.322588] Kernel panic - not syncing: panic_on_warn set ... [ 65.322588] [ 65.329957] CPU: 1 PID: 7633 Comm: syz-executor164 Tainted: G B 4.19.75 #0 [ 65.338260] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 65.347591] Call Trace: [ 65.350160] dump_stack+0x172/0x1f0 [ 65.353772] ? wait_consider_task+0x1b51/0x3910 [ 65.358422] panic+0x263/0x507 [ 65.361612] ? __warn_printk+0xf3/0xf3 [ 65.365495] ? retint_kernel+0x2d/0x2d [ 65.369376] ? trace_hardirqs_on+0x5e/0x220 [ 65.373683] ? wait_consider_task+0x1b51/0x3910 [ 65.378607] kasan_end_report+0x47/0x4f [ 65.383347] kasan_report.cold+0xa9/0x2ba [ 65.387507] __asan_report_load4_noabort+0x14/0x20 [ 65.392444] wait_consider_task+0x1b51/0x3910 [ 65.396925] ? lockdep_hardirqs_on+0x415/0x5d0 [ 65.401492] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 65.406589] ? add_wait_queue+0x112/0x170 [ 65.410727] ? release_task+0x1630/0x1630 [ 65.414887] ? lock_acquire+0x16f/0x3f0 [ 65.418855] ? do_wait+0x3aa/0x9d0 [ 65.422385] ? kasan_check_write+0x14/0x20 [ 65.426611] do_wait+0x439/0x9d0 [ 65.429962] ? wait_consider_task+0x3910/0x3910 [ 65.434610] kernel_wait4+0x171/0x290 [ 65.438397] ? __ia32_sys_waitid+0x140/0x140 [ 65.442787] ? task_stopped_code+0x180/0x180 [ 65.447187] __do_sys_wait4+0x147/0x160 [ 65.451153] ? kernel_wait4+0x290/0x290 [ 65.455110] ? _copy_to_user+0xc9/0x120 [ 65.459077] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 65.464595] ? put_timespec64+0xda/0x140 [ 65.468646] ? nsecs_to_jiffies+0x30/0x30 [ 65.472777] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 65.477522] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 65.482259] ? do_syscall_64+0x26/0x620 [ 65.486213] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 65.491586] ? do_syscall_64+0x26/0x620 [ 65.495554] __x64_sys_wait4+0x97/0xf0 [ 65.499442] do_syscall_64+0xfd/0x620 [ 65.503242] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 65.508415] RIP: 0033:0x4013ba [ 65.511591] Code: c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 8b 05 3e 23 2d 00 85 c0 75 36 45 31 d2 48 63 d2 48 63 ff b8 3d 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 06 c3 0f 1f 44 00 00 48 c7 c2 d0 ff ff ff f7 [ 65.531512] RSP: 002b:00007ffc8948fa38 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 65.539201] RAX: ffffffffffffffda RBX: 0000000000001dd2 RCX: 00000000004013ba [ 65.546454] RDX: 0000000040000001 RSI: 00007ffc8948fa44 RDI: ffffffffffffffff [ 65.553732] RBP: 000000000000fd19 R08: 0000000000000000 R09: 0000555556a8e880 [ 65.561002] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402370 [ 65.568267] R13: 0000000000402400 R14: 0000000000000000 R15: 0000000000000000 [ 65.576258] Kernel Offset: disabled [ 65.579893] Rebooting in 86400 seconds..