[....] 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. [ 37.612579] audit: type=1800 audit(1569504482.883:33): pid=7320 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 [ 37.635895] audit: type=1800 audit(1569504482.883:34): pid=7320 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: [ 39.003569] audit: type=1400 audit(1569504484.273:35): avc: denied { map } for pid=7494 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 '10.128.0.149' (ECDSA) to the list of known hosts. executing program [ 45.431673] audit: type=1400 audit(1569504490.703:36): avc: denied { map } for pid=7507 comm="syz-executor514" path="/root/syz-executor514353767" 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 [ 45.454407] ================================================================== [ 45.465351] BUG: KASAN: use-after-free in wait_consider_task+0x1b51/0x3910 [ 45.472410] Read of size 4 at addr ffff888096f9846c by task syz-executor514/7507 [ 45.479934] [ 45.481556] CPU: 0 PID: 7507 Comm: syz-executor514 Not tainted 4.19.75 #0 [ 45.488464] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 45.497803] Call Trace: [ 45.500378] dump_stack+0x172/0x1f0 [ 45.503993] ? wait_consider_task+0x1b51/0x3910 [ 45.508650] print_address_description.cold+0x7c/0x20d [ 45.513911] ? wait_consider_task+0x1b51/0x3910 [ 45.518564] kasan_report.cold+0x8c/0x2ba [ 45.522698] __asan_report_load4_noabort+0x14/0x20 [ 45.527620] wait_consider_task+0x1b51/0x3910 [ 45.532110] ? lockdep_hardirqs_on+0x415/0x5d0 [ 45.536677] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 45.541775] ? add_wait_queue+0x112/0x170 [ 45.545909] ? release_task+0x1630/0x1630 [ 45.550037] ? lock_acquire+0x16f/0x3f0 [ 45.554005] ? do_wait+0x3aa/0x9d0 [ 45.557529] ? kasan_check_write+0x14/0x20 [ 45.561748] do_wait+0x439/0x9d0 [ 45.565102] ? wait_consider_task+0x3910/0x3910 [ 45.569755] kernel_wait4+0x171/0x290 [ 45.573548] ? __ia32_sys_waitid+0x140/0x140 [ 45.577941] ? task_stopped_code+0x180/0x180 [ 45.582350] __do_sys_wait4+0x147/0x160 [ 45.586305] ? kernel_wait4+0x290/0x290 [ 45.590262] ? _copy_to_user+0xc9/0x120 [ 45.594225] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 45.599752] ? put_timespec64+0xda/0x140 [ 45.603796] ? nsecs_to_jiffies+0x30/0x30 [ 45.607933] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 45.612681] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 45.617420] ? do_syscall_64+0x26/0x620 [ 45.621390] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 45.626736] ? do_syscall_64+0x26/0x620 [ 45.630696] __x64_sys_wait4+0x97/0xf0 [ 45.634568] do_syscall_64+0xfd/0x620 [ 45.638354] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 45.643526] RIP: 0033:0x40110a [ 45.646700] Code: c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 8b 05 ce 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 [ 45.665584] RSP: 002b:00007ffe7511be28 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 45.673277] RAX: ffffffffffffffda RBX: 0000000000001d54 RCX: 000000000040110a [ 45.680527] RDX: 0000000040000001 RSI: 00007ffe7511be34 RDI: ffffffffffffffff [ 45.687778] RBP: 000000000000b155 R08: 0000000000000000 R09: 0000555557268880 [ 45.695031] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004020c0 [ 45.702389] R13: 0000000000402150 R14: 0000000000000000 R15: 0000000000000000 [ 45.709646] [ 45.711254] Allocated by task 7507: [ 45.714872] save_stack+0x45/0xd0 [ 45.718315] kasan_kmalloc+0xce/0xf0 [ 45.722013] kasan_slab_alloc+0xf/0x20 [ 45.725887] kmem_cache_alloc_node+0x144/0x710 [ 45.730448] copy_process.part.0+0x1ce0/0x7a30 [ 45.735011] _do_fork+0x257/0xfd0 [ 45.738446] __x64_sys_clone+0xbf/0x150 [ 45.742400] do_syscall_64+0xfd/0x620 [ 45.746187] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 45.751364] [ 45.752972] Freed by task 7509: [ 45.756234] save_stack+0x45/0xd0 [ 45.759671] __kasan_slab_free+0x102/0x150 [ 45.763896] kasan_slab_free+0xe/0x10 [ 45.767677] kmem_cache_free+0x86/0x260 [ 45.771630] free_task+0xdd/0x120 [ 45.775087] __put_task_struct+0x20f/0x4c0 [ 45.779314] finish_task_switch+0x52b/0x780 [ 45.783627] __schedule+0x86e/0x1dc0 [ 45.787324] preempt_schedule_irq+0xb5/0x140 [ 45.791714] retint_kernel+0x1b/0x2d [ 45.795419] do_exit+0x1cd5/0x2fa0 [ 45.798937] kthread+0x2c3/0x420 [ 45.802285] ret_from_fork+0x24/0x30 [ 45.805976] [ 45.807592] The buggy address belongs to the object at ffff888096f98000 [ 45.807592] which belongs to the cache task_struct of size 6080 [ 45.820331] The buggy address is located 1132 bytes inside of [ 45.820331] 6080-byte region [ffff888096f98000, ffff888096f997c0) [ 45.832360] The buggy address belongs to the page: [ 45.837306] page:ffffea00025be600 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 [ 45.847261] flags: 0x1fffc0000008100(slab|head) [ 45.851921] raw: 01fffc0000008100 ffffea00027cc888 ffffea00025c9588 ffff88812c26d800 [ 45.859785] raw: 0000000000000000 ffff888096f98000 0000000100000001 0000000000000000 [ 45.867728] page dumped because: kasan: bad access detected [ 45.873414] [ 45.875021] Memory state around the buggy address: [ 45.879932] ffff888096f98300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 45.887282] ffff888096f98380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 45.894634] >ffff888096f98400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 45.902029] ^ [ 45.908823] ffff888096f98480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 45.916175] ffff888096f98500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 45.923516] ================================================================== [ 45.930854] Disabling lock debugging due to kernel taint [ 45.936499] Kernel panic - not syncing: panic_on_warn set ... [ 45.936499] [ 45.943866] CPU: 0 PID: 7507 Comm: syz-executor514 Tainted: G B 4.19.75 #0 [ 45.952165] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 45.961497] Call Trace: [ 45.964071] dump_stack+0x172/0x1f0 [ 45.967685] ? wait_consider_task+0x1b51/0x3910 [ 45.972343] panic+0x263/0x507 [ 45.975516] ? __warn_printk+0xf3/0xf3 [ 45.979382] ? retint_kernel+0x2d/0x2d [ 45.983254] ? trace_hardirqs_on+0x5e/0x220 [ 45.987556] ? wait_consider_task+0x1b51/0x3910 [ 45.992219] kasan_end_report+0x47/0x4f [ 45.996176] kasan_report.cold+0xa9/0x2ba [ 46.000313] __asan_report_load4_noabort+0x14/0x20 [ 46.005222] wait_consider_task+0x1b51/0x3910 [ 46.009705] ? lockdep_hardirqs_on+0x415/0x5d0 [ 46.014283] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 46.019364] ? add_wait_queue+0x112/0x170 [ 46.023508] ? release_task+0x1630/0x1630 [ 46.027641] ? lock_acquire+0x16f/0x3f0 [ 46.031598] ? do_wait+0x3aa/0x9d0 [ 46.035121] ? kasan_check_write+0x14/0x20 [ 46.039337] do_wait+0x439/0x9d0 [ 46.042699] ? wait_consider_task+0x3910/0x3910 [ 46.047358] kernel_wait4+0x171/0x290 [ 46.051140] ? __ia32_sys_waitid+0x140/0x140 [ 46.055528] ? task_stopped_code+0x180/0x180 [ 46.059918] __do_sys_wait4+0x147/0x160 [ 46.063876] ? kernel_wait4+0x290/0x290 [ 46.067831] ? _copy_to_user+0xc9/0x120 [ 46.071800] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 46.077419] ? put_timespec64+0xda/0x140 [ 46.081468] ? nsecs_to_jiffies+0x30/0x30 [ 46.085601] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 46.090378] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 46.095118] ? do_syscall_64+0x26/0x620 [ 46.099079] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 46.104426] ? do_syscall_64+0x26/0x620 [ 46.108388] __x64_sys_wait4+0x97/0xf0 [ 46.112259] do_syscall_64+0xfd/0x620 [ 46.116046] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 46.121218] RIP: 0033:0x40110a [ 46.124390] Code: c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 8b 05 ce 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 [ 46.143274] RSP: 002b:00007ffe7511be28 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 46.150968] RAX: ffffffffffffffda RBX: 0000000000001d54 RCX: 000000000040110a [ 46.158346] RDX: 0000000040000001 RSI: 00007ffe7511be34 RDI: ffffffffffffffff [ 46.165596] RBP: 000000000000b155 R08: 0000000000000000 R09: 0000555557268880 [ 46.172846] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004020c0 [ 46.180093] R13: 0000000000402150 R14: 0000000000000000 R15: 0000000000000000 [ 46.189059] Kernel Offset: disabled [ 46.192682] Rebooting in 86400 seconds..