[ 39.612776] audit: type=1800 audit(1569456973.794:31): pid=7486 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:kernel_t:s0 op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2469 res=0 [ 39.641761] audit: type=1800 audit(1569456973.794:32): pid=7486 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:kernel_t:s0 op=collect_data cause=failed(directio) comm="startpar" name="ssh" dev="sda1" ino=2450 res=0 Starting mcstransd: [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.10.21' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 65.496765] kauditd_printk_skb: 3 callbacks suppressed [ 65.496780] audit: type=1400 audit(1569456999.754:36): avc: denied { map } for pid=7674 comm="syz-executor020" path="/root/syz-executor020374006" 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 [ 65.543918] ================================================================== [ 65.551799] BUG: KASAN: use-after-free in wait_consider_task+0x1b51/0x3910 [ 65.559112] Read of size 4 at addr ffff88808af4472c by task sshd/7672 [ 65.566014] [ 65.567689] CPU: 0 PID: 7672 Comm: sshd Not tainted 4.19.75 #0 [ 65.573644] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 65.583007] Call Trace: [ 65.585607] dump_stack+0x172/0x1f0 [ 65.589228] ? wait_consider_task+0x1b51/0x3910 [ 65.593902] print_address_description.cold+0x7c/0x20d [ 65.599424] ? wait_consider_task+0x1b51/0x3910 [ 65.604096] kasan_report.cold+0x8c/0x2ba [ 65.608414] __asan_report_load4_noabort+0x14/0x20 [ 65.613374] wait_consider_task+0x1b51/0x3910 [ 65.617901] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 65.623147] ? add_wait_queue+0x112/0x170 [ 65.627423] ? release_task+0x1630/0x1630 [ 65.631590] ? lock_acquire+0x16f/0x3f0 [ 65.635656] ? do_wait+0x3aa/0x9d0 [ 65.639194] ? kasan_check_write+0x14/0x20 [ 65.643429] do_wait+0x439/0x9d0 [ 65.646800] ? wait_consider_task+0x3910/0x3910 [ 65.651486] ? mark_held_locks+0x100/0x100 [ 65.655727] kernel_wait4+0x171/0x290 [ 65.659529] ? __ia32_sys_waitid+0x140/0x140 [ 65.663984] ? task_stopped_code+0x180/0x180 [ 65.668426] __do_sys_wait4+0x147/0x160 [ 65.672432] ? kernel_wait4+0x290/0x290 [ 65.676419] ? kasan_check_read+0x11/0x20 [ 65.680594] ? _copy_to_user+0xc9/0x120 [ 65.684563] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 65.690106] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 65.695235] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 65.700087] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 65.705015] ? do_syscall_64+0x26/0x620 [ 65.708991] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 65.714375] ? do_syscall_64+0x26/0x620 [ 65.718382] __x64_sys_wait4+0x97/0xf0 [ 65.722267] do_syscall_64+0xfd/0x620 [ 65.726158] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 65.731397] RIP: 0033:0x7f1669bc4a3e [ 65.735105] 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 [ 65.754694] RSP: 002b:00007ffe48a3eef0 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 65.762549] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f1669bc4a3e [ 65.770714] RDX: 0000000000000001 RSI: 00007ffe48a3ef2c RDI: ffffffffffffffff [ 65.778115] RBP: 000055d34bc34c88 R08: 00007ffe48a3eff0 R09: 0101010101010101 [ 65.785568] R10: 0000000000000000 R11: 0000000000000246 R12: 000055d34be0baf0 [ 65.793760] R13: 000055d34bc32fb4 R14: 0000000000000028 R15: 000055d34bc34ca0 [ 65.801622] [ 65.803442] Allocated by task 7672: [ 65.807081] save_stack+0x45/0xd0 [ 65.810632] kasan_kmalloc+0xce/0xf0 [ 65.814352] kasan_slab_alloc+0xf/0x20 [ 65.818278] kmem_cache_alloc_node+0x144/0x710 [ 65.823247] copy_process.part.0+0x1ce0/0x7a30 [ 65.827839] _do_fork+0x257/0xfd0 [ 65.831890] __x64_sys_clone+0xbf/0x150 [ 65.835873] do_syscall_64+0xfd/0x620 [ 65.840043] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 65.845310] [ 65.846928] Freed by task 0: [ 65.849962] save_stack+0x45/0xd0 [ 65.853873] __kasan_slab_free+0x102/0x150 [ 65.858135] kasan_slab_free+0xe/0x10 [ 65.862305] kmem_cache_free+0x86/0x260 [ 65.866540] free_task+0xdd/0x120 [ 65.869983] __put_task_struct+0x20f/0x4c0 [ 65.874206] finish_task_switch+0x52b/0x780 [ 65.878570] __schedule+0x86e/0x1dc0 [ 65.882288] schedule_idle+0x58/0x80 [ 65.886030] do_idle+0x192/0x560 [ 65.889416] cpu_startup_entry+0xc8/0xe0 [ 65.893626] start_secondary+0x3e8/0x5b0 [ 65.897700] secondary_startup_64+0xa4/0xb0 [ 65.902157] [ 65.903786] The buggy address belongs to the object at ffff88808af442c0 [ 65.903786] which belongs to the cache task_struct of size 6080 [ 65.916625] The buggy address is located 1132 bytes inside of [ 65.916625] 6080-byte region [ffff88808af442c0, ffff88808af45a80) [ 65.928671] The buggy address belongs to the page: [ 65.933594] page:ffffea00022bd100 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 [ 65.943560] flags: 0x1fffc0000008100(slab|head) [ 65.948224] raw: 01fffc0000008100 ffffea0002268088 ffffea00022c2c08 ffff88812c26d800 [ 65.956097] raw: 0000000000000000 ffff88808af442c0 0000000100000001 0000000000000000 [ 65.964384] page dumped because: kasan: bad access detected [ 65.970118] [ 65.971758] Memory state around the buggy address: [ 65.976744] ffff88808af44600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 65.984267] ffff88808af44680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 65.991843] >ffff88808af44700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 65.999367] ^ [ 66.004065] ffff88808af44780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 66.011441] ffff88808af44800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 66.018801] ================================================================== [ 66.026278] Disabling lock debugging due to kernel taint [ 66.031911] Kernel panic - not syncing: panic_on_warn set ... [ 66.031911] [ 66.039299] CPU: 0 PID: 7672 Comm: sshd Tainted: G B 4.19.75 #0 [ 66.046844] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 66.056207] Call Trace: [ 66.058808] dump_stack+0x172/0x1f0 [ 66.062772] ? wait_consider_task+0x1b51/0x3910 [ 66.067459] panic+0x263/0x507 [ 66.070650] ? __warn_printk+0xf3/0xf3 [ 66.075399] ? retint_kernel+0x2d/0x2d [ 66.079487] ? trace_hardirqs_on+0x5e/0x220 [ 66.083951] ? wait_consider_task+0x1b51/0x3910 [ 66.088655] kasan_end_report+0x47/0x4f [ 66.092914] kasan_report.cold+0xa9/0x2ba [ 66.097092] __asan_report_load4_noabort+0x14/0x20 [ 66.102068] wait_consider_task+0x1b51/0x3910 [ 66.106589] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 66.111706] ? add_wait_queue+0x112/0x170 [ 66.115864] ? release_task+0x1630/0x1630 [ 66.120182] ? lock_acquire+0x16f/0x3f0 [ 66.124508] ? do_wait+0x3aa/0x9d0 [ 66.128740] ? kasan_check_write+0x14/0x20 [ 66.133369] do_wait+0x439/0x9d0 [ 66.136953] ? wait_consider_task+0x3910/0x3910 [ 66.142120] ? mark_held_locks+0x100/0x100 [ 66.146361] kernel_wait4+0x171/0x290 [ 66.150310] ? __ia32_sys_waitid+0x140/0x140 [ 66.154721] ? task_stopped_code+0x180/0x180 [ 66.159251] __do_sys_wait4+0x147/0x160 [ 66.163263] ? kernel_wait4+0x290/0x290 [ 66.167248] ? kasan_check_read+0x11/0x20 [ 66.171546] ? _copy_to_user+0xc9/0x120 [ 66.175523] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 66.181070] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 66.186099] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 66.191060] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 66.195950] ? do_syscall_64+0x26/0x620 [ 66.200040] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.205417] ? do_syscall_64+0x26/0x620 [ 66.209512] __x64_sys_wait4+0x97/0xf0 [ 66.213602] do_syscall_64+0xfd/0x620 [ 66.217405] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.222706] RIP: 0033:0x7f1669bc4a3e [ 66.226421] 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 [ 66.245928] RSP: 002b:00007ffe48a3eef0 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 66.253645] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f1669bc4a3e [ 66.261377] RDX: 0000000000000001 RSI: 00007ffe48a3ef2c RDI: ffffffffffffffff [ 66.268847] RBP: 000055d34bc34c88 R08: 00007ffe48a3eff0 R09: 0101010101010101 [ 66.276379] R10: 0000000000000000 R11: 0000000000000246 R12: 000055d34be0baf0 [ 66.284026] R13: 000055d34bc32fb4 R14: 0000000000000028 R15: 000055d34bc34ca0 [ 66.293285] Kernel Offset: disabled [ 66.296935] Rebooting in 86400 seconds..