[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. Starting mcstransd: [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [ 40.410135] audit: type=1800 audit(1569283380.397:33): pid=7400 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 [ 40.432420] audit: type=1800 audit(1569283380.397:34): pid=7400 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: [ 42.643002] audit: type=1400 audit(1569283382.637:35): avc: denied { map } for pid=7575 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 '10.128.10.3' (ECDSA) to the list of known hosts. executing program [ 61.545422] audit: type=1400 audit(1569283401.537:36): avc: denied { map } for pid=7587 comm="syz-executor508" path="/root/syz-executor508621752" 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 [ 61.575182] ================================================================== [ 61.582655] BUG: KASAN: use-after-free in wait_consider_task+0x1b51/0x3910 [ 61.589762] Read of size 4 at addr ffff8880a1eec8ac by task syz-executor508/7587 [ 61.597275] [ 61.598891] CPU: 0 PID: 7587 Comm: syz-executor508 Not tainted 4.19.75 #0 [ 61.605797] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 61.615142] Call Trace: [ 61.617719] dump_stack+0x172/0x1f0 [ 61.621334] ? wait_consider_task+0x1b51/0x3910 [ 61.625989] print_address_description.cold+0x7c/0x20d [ 61.631251] ? wait_consider_task+0x1b51/0x3910 [ 61.635929] kasan_report.cold+0x8c/0x2ba [ 61.640076] __asan_report_load4_noabort+0x14/0x20 [ 61.644991] wait_consider_task+0x1b51/0x3910 [ 61.649480] ? lockdep_hardirqs_on+0x415/0x5d0 [ 61.654059] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 61.659145] ? add_wait_queue+0x112/0x170 [ 61.663282] ? release_task+0x1630/0x1630 [ 61.667418] ? lock_acquire+0x16f/0x3f0 [ 61.671376] ? do_wait+0x3aa/0x9d0 [ 61.674904] ? kasan_check_write+0x14/0x20 [ 61.679122] do_wait+0x439/0x9d0 [ 61.682481] ? wait_consider_task+0x3910/0x3910 [ 61.687200] kernel_wait4+0x171/0x290 [ 61.691035] ? __ia32_sys_waitid+0x140/0x140 [ 61.695446] ? task_stopped_code+0x180/0x180 [ 61.699860] __do_sys_wait4+0x147/0x160 [ 61.703839] ? kernel_wait4+0x290/0x290 [ 61.707806] ? _copy_to_user+0xc9/0x120 [ 61.711769] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 61.717303] ? put_timespec64+0xda/0x140 [ 61.721345] ? nsecs_to_jiffies+0x30/0x30 [ 61.725490] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 61.730230] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 61.735002] ? do_syscall_64+0x26/0x620 [ 61.739163] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 61.744513] ? do_syscall_64+0x26/0x620 [ 61.748476] __x64_sys_wait4+0x97/0xf0 [ 61.752352] do_syscall_64+0xfd/0x620 [ 61.756141] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 61.761312] RIP: 0033:0x40111a [ 61.764761] Code: c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 8b 05 be 15 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 [ 61.783661] RSP: 002b:00007ffd7a791788 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 61.791357] RAX: ffffffffffffffda RBX: 0000000000001da4 RCX: 000000000040111a [ 61.798649] RDX: 0000000040000001 RSI: 00007ffd7a791794 RDI: ffffffffffffffff [ 61.805922] RBP: 000000000000f04f R08: 0000000000000000 R09: 0000555556f1f880 [ 61.813192] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004020d0 [ 61.820447] R13: 0000000000402160 R14: 0000000000000000 R15: 0000000000000000 [ 61.827710] [ 61.829328] Allocated by task 7587: [ 61.832947] save_stack+0x45/0xd0 [ 61.836387] kasan_kmalloc+0xce/0xf0 [ 61.840085] kasan_slab_alloc+0xf/0x20 [ 61.843956] kmem_cache_alloc_node+0x144/0x710 [ 61.848521] copy_process.part.0+0x1ce0/0x7a30 [ 61.853102] _do_fork+0x257/0xfd0 [ 61.856574] __x64_sys_clone+0xbf/0x150 [ 61.860535] do_syscall_64+0xfd/0x620 [ 61.864322] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 61.869489] [ 61.871097] Freed by task 0: [ 61.874101] save_stack+0x45/0xd0 [ 61.877536] __kasan_slab_free+0x102/0x150 [ 61.881753] kasan_slab_free+0xe/0x10 [ 61.885536] kmem_cache_free+0x86/0x260 [ 61.889493] free_task+0xdd/0x120 [ 61.892928] __put_task_struct+0x20f/0x4c0 [ 61.897143] finish_task_switch+0x52b/0x780 [ 61.901457] __schedule+0x86e/0x1dc0 [ 61.905153] schedule_idle+0x58/0x80 [ 61.908848] do_idle+0x192/0x560 [ 61.912201] cpu_startup_entry+0xc8/0xe0 [ 61.916245] start_secondary+0x3e8/0x5b0 [ 61.920288] secondary_startup_64+0xa4/0xb0 [ 61.924586] [ 61.926205] The buggy address belongs to the object at ffff8880a1eec440 [ 61.926205] which belongs to the cache task_struct of size 6080 [ 61.938933] The buggy address is located 1132 bytes inside of [ 61.938933] 6080-byte region [ffff8880a1eec440, ffff8880a1eedc00) [ 61.951367] The buggy address belongs to the page: [ 61.956348] page:ffffea000287bb00 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 [ 61.966328] flags: 0x1fffc0000008100(slab|head) [ 61.970991] raw: 01fffc0000008100 ffffea000287c288 ffffea000287cb08 ffff88812c26d800 [ 61.978864] raw: 0000000000000000 ffff8880a1eec440 0000000100000001 0000000000000000 [ 61.986898] page dumped because: kasan: bad access detected [ 61.992591] [ 61.994198] Memory state around the buggy address: [ 61.999110] ffff8880a1eec780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 62.006456] ffff8880a1eec800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 62.013899] >ffff8880a1eec880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 62.021262] ^ [ 62.025936] ffff8880a1eec900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 62.035365] ffff8880a1eec980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 62.042706] ================================================================== [ 62.050044] Disabling lock debugging due to kernel taint [ 62.055634] Kernel panic - not syncing: panic_on_warn set ... [ 62.055634] [ 62.063023] CPU: 0 PID: 7587 Comm: syz-executor508 Tainted: G B 4.19.75 #0 [ 62.071767] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 62.081109] Call Trace: [ 62.083688] dump_stack+0x172/0x1f0 [ 62.087303] ? wait_consider_task+0x1b51/0x3910 [ 62.091985] panic+0x263/0x507 [ 62.095251] ? __warn_printk+0xf3/0xf3 [ 62.099132] ? retint_kernel+0x2d/0x2d [ 62.103126] ? trace_hardirqs_on+0x5e/0x220 [ 62.107453] ? wait_consider_task+0x1b51/0x3910 [ 62.112246] kasan_end_report+0x47/0x4f [ 62.116431] kasan_report.cold+0xa9/0x2ba [ 62.120565] __asan_report_load4_noabort+0x14/0x20 [ 62.125479] wait_consider_task+0x1b51/0x3910 [ 62.129956] ? lockdep_hardirqs_on+0x415/0x5d0 [ 62.134646] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 62.139766] ? add_wait_queue+0x112/0x170 [ 62.143907] ? release_task+0x1630/0x1630 [ 62.148040] ? lock_acquire+0x16f/0x3f0 [ 62.151996] ? do_wait+0x3aa/0x9d0 [ 62.155526] ? kasan_check_write+0x14/0x20 [ 62.159758] do_wait+0x439/0x9d0 [ 62.163998] ? wait_consider_task+0x3910/0x3910 [ 62.168653] kernel_wait4+0x171/0x290 [ 62.172549] ? __ia32_sys_waitid+0x140/0x140 [ 62.176941] ? task_stopped_code+0x180/0x180 [ 62.181346] __do_sys_wait4+0x147/0x160 [ 62.185305] ? kernel_wait4+0x290/0x290 [ 62.189260] ? _copy_to_user+0xc9/0x120 [ 62.193325] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 62.198843] ? put_timespec64+0xda/0x140 [ 62.202910] ? nsecs_to_jiffies+0x30/0x30 [ 62.207057] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 62.211805] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 62.216573] ? do_syscall_64+0x26/0x620 [ 62.220539] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 62.225979] ? do_syscall_64+0x26/0x620 [ 62.229945] __x64_sys_wait4+0x97/0xf0 [ 62.233896] do_syscall_64+0xfd/0x620 [ 62.237685] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 62.243064] RIP: 0033:0x40111a [ 62.246242] Code: c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 8b 05 be 15 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 [ 62.265126] RSP: 002b:00007ffd7a791788 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 62.272819] RAX: ffffffffffffffda RBX: 0000000000001da4 RCX: 000000000040111a [ 62.280072] RDX: 0000000040000001 RSI: 00007ffd7a791794 RDI: ffffffffffffffff [ 62.287332] RBP: 000000000000f04f R08: 0000000000000000 R09: 0000555556f1f880 [ 62.294726] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004020d0 [ 62.301995] R13: 0000000000402160 R14: 0000000000000000 R15: 0000000000000000 [ 62.311358] Kernel Offset: disabled [ 62.315022] Rebooting in 86400 seconds..