[ 40.252811] audit: type=1800 audit(1569054646.332:32): pid=7507 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 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. [ 41.012701] audit: type=1800 audit(1569054647.182:33): pid=7507 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 Warning: Permanently added '10.128.0.249' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 49.673093] kauditd_printk_skb: 2 callbacks suppressed [ 49.673108] audit: type=1400 audit(1569054655.842:36): avc: denied { map } for pid=7695 comm="syz-executor503" path="/root/syz-executor503652993" 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 [ 49.717647] ================================================================== [ 49.725095] BUG: KASAN: use-after-free in wait_consider_task+0x1b51/0x3910 [ 49.732102] Read of size 4 at addr ffff88809bda44ec by task sshd/7693 [ 49.738663] [ 49.740283] CPU: 1 PID: 7693 Comm: sshd Not tainted 4.19.75 #0 [ 49.746235] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 49.755581] Call Trace: [ 49.758160] dump_stack+0x172/0x1f0 [ 49.761792] ? wait_consider_task+0x1b51/0x3910 [ 49.766449] print_address_description.cold+0x7c/0x20d [ 49.771709] ? wait_consider_task+0x1b51/0x3910 [ 49.776361] kasan_report.cold+0x8c/0x2ba [ 49.780504] __asan_report_load4_noabort+0x14/0x20 [ 49.785419] wait_consider_task+0x1b51/0x3910 [ 49.789900] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 49.794983] ? add_wait_queue+0x112/0x170 [ 49.799125] ? release_task+0x1630/0x1630 [ 49.803270] ? lock_acquire+0x16f/0x3f0 [ 49.807235] ? do_wait+0x3aa/0x9d0 [ 49.810774] ? kasan_check_write+0x14/0x20 [ 49.814993] do_wait+0x439/0x9d0 [ 49.818357] ? wait_consider_task+0x3910/0x3910 [ 49.823010] ? mark_held_locks+0x100/0x100 [ 49.827231] kernel_wait4+0x171/0x290 [ 49.831016] ? __ia32_sys_waitid+0x140/0x140 [ 49.836388] ? task_stopped_code+0x180/0x180 [ 49.840797] __do_sys_wait4+0x147/0x160 [ 49.844752] ? kernel_wait4+0x290/0x290 [ 49.848719] ? kasan_check_read+0x11/0x20 [ 49.852851] ? _copy_to_user+0xc9/0x120 [ 49.856814] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 49.862342] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 49.867352] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 49.872091] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 49.876827] ? do_syscall_64+0x26/0x620 [ 49.880783] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 49.886128] ? do_syscall_64+0x26/0x620 [ 49.890098] __x64_sys_wait4+0x97/0xf0 [ 49.893971] do_syscall_64+0xfd/0x620 [ 49.897772] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 49.902951] RIP: 0033:0x7f1d9d01aa3e [ 49.906644] 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 [ 49.925525] RSP: 002b:00007ffd3aa46f50 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 49.933281] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f1d9d01aa3e [ 49.940537] RDX: 0000000000000001 RSI: 00007ffd3aa46f8c RDI: ffffffffffffffff [ 49.947788] RBP: 00005589d35dbc88 R08: 00007ffd3aa47050 R09: 0101010101010101 [ 49.955052] R10: 0000000000000000 R11: 0000000000000246 R12: 00005589d3fd5db0 [ 49.962432] R13: 00005589d35d9fb4 R14: 0000000000000028 R15: 00005589d35dbca0 [ 49.969716] [ 49.971329] Allocated by task 7693: [ 49.974956] save_stack+0x45/0xd0 [ 49.978391] kasan_kmalloc+0xce/0xf0 [ 49.982088] kasan_slab_alloc+0xf/0x20 [ 49.985959] kmem_cache_alloc_node+0x144/0x710 [ 49.990524] copy_process.part.0+0x1ce0/0x7a30 [ 49.995086] _do_fork+0x257/0xfd0 [ 49.998520] __x64_sys_clone+0xbf/0x150 [ 50.002481] do_syscall_64+0xfd/0x620 [ 50.006274] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 50.011441] [ 50.013058] Freed by task 0: [ 50.016058] save_stack+0x45/0xd0 [ 50.019493] __kasan_slab_free+0x102/0x150 [ 50.023706] kasan_slab_free+0xe/0x10 [ 50.027487] kmem_cache_free+0x86/0x260 [ 50.031439] free_task+0xdd/0x120 [ 50.034878] __put_task_struct+0x20f/0x4c0 [ 50.039095] finish_task_switch+0x52b/0x780 [ 50.043399] __schedule+0x86e/0x1dc0 [ 50.047102] schedule_idle+0x58/0x80 [ 50.050793] do_idle+0x192/0x560 [ 50.054138] cpu_startup_entry+0xc8/0xe0 [ 50.058180] rest_init+0x219/0x222 [ 50.061701] start_kernel+0x88c/0x8c5 [ 50.065482] x86_64_start_reservations+0x29/0x2b [ 50.070231] x86_64_start_kernel+0x77/0x7b [ 50.074457] secondary_startup_64+0xa4/0xb0 [ 50.078759] [ 50.080374] The buggy address belongs to the object at ffff88809bda4080 [ 50.080374] which belongs to the cache task_struct of size 6080 [ 50.093114] The buggy address is located 1132 bytes inside of [ 50.093114] 6080-byte region [ffff88809bda4080, ffff88809bda5840) [ 50.105143] The buggy address belongs to the page: [ 50.110054] page:ffffea00026f6900 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 [ 50.120015] flags: 0x1fffc0000008100(slab|head) [ 50.124668] raw: 01fffc0000008100 ffffea0002755208 ffffea00026f8e88 ffff88812c26d800 [ 50.132543] raw: 0000000000000000 ffff88809bda4080 0000000100000001 0000000000000000 [ 50.140398] page dumped because: kasan: bad access detected [ 50.146085] [ 50.147690] Memory state around the buggy address: [ 50.152600] ffff88809bda4380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 50.159938] ffff88809bda4400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 50.167283] >ffff88809bda4480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 50.174619] ^ [ 50.181350] ffff88809bda4500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 50.188698] ffff88809bda4580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 50.196043] ================================================================== [ 50.203390] Disabling lock debugging due to kernel taint [ 50.208922] Kernel panic - not syncing: panic_on_warn set ... [ 50.208922] [ 50.216292] CPU: 1 PID: 7693 Comm: sshd Tainted: G B 4.19.75 #0 [ 50.223720] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 50.233053] Call Trace: [ 50.235636] dump_stack+0x172/0x1f0 [ 50.239247] ? wait_consider_task+0x1b51/0x3910 [ 50.244070] panic+0x263/0x507 [ 50.247243] ? __warn_printk+0xf3/0xf3 [ 50.251180] ? retint_kernel+0x2d/0x2d [ 50.255057] ? trace_hardirqs_on+0x5e/0x220 [ 50.259388] ? wait_consider_task+0x1b51/0x3910 [ 50.264052] kasan_end_report+0x47/0x4f [ 50.268102] kasan_report.cold+0xa9/0x2ba [ 50.272242] __asan_report_load4_noabort+0x14/0x20 [ 50.277157] wait_consider_task+0x1b51/0x3910 [ 50.281634] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 50.286715] ? add_wait_queue+0x112/0x170 [ 50.290846] ? release_task+0x1630/0x1630 [ 50.294976] ? lock_acquire+0x16f/0x3f0 [ 50.298930] ? do_wait+0x3aa/0x9d0 [ 50.302451] ? kasan_check_write+0x14/0x20 [ 50.306668] do_wait+0x439/0x9d0 [ 50.310015] ? wait_consider_task+0x3910/0x3910 [ 50.314664] ? mark_held_locks+0x100/0x100 [ 50.318882] kernel_wait4+0x171/0x290 [ 50.322668] ? __ia32_sys_waitid+0x140/0x140 [ 50.327056] ? task_stopped_code+0x180/0x180 [ 50.331458] __do_sys_wait4+0x147/0x160 [ 50.335410] ? kernel_wait4+0x290/0x290 [ 50.339374] ? kasan_check_read+0x11/0x20 [ 50.343502] ? _copy_to_user+0xc9/0x120 [ 50.347459] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 50.352977] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 50.357975] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 50.362722] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 50.367459] ? do_syscall_64+0x26/0x620 [ 50.371422] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 50.376771] ? do_syscall_64+0x26/0x620 [ 50.380729] __x64_sys_wait4+0x97/0xf0 [ 50.384611] do_syscall_64+0xfd/0x620 [ 50.388401] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 50.393580] RIP: 0033:0x7f1d9d01aa3e [ 50.397278] 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 [ 50.416158] RSP: 002b:00007ffd3aa46f50 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 50.423847] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f1d9d01aa3e [ 50.431097] RDX: 0000000000000001 RSI: 00007ffd3aa46f8c RDI: ffffffffffffffff [ 50.438355] RBP: 00005589d35dbc88 R08: 00007ffd3aa47050 R09: 0101010101010101 [ 50.445603] R10: 0000000000000000 R11: 0000000000000246 R12: 00005589d3fd5db0 [ 50.452849] R13: 00005589d35d9fb4 R14: 0000000000000028 R15: 00005589d35dbca0 [ 50.460972] Kernel Offset: disabled [ 50.464606] Rebooting in 86400 seconds..