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. [ 39.084468] audit: type=1800 audit(1569057634.889:33): pid=7332 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 syzkaller login: [ 44.951876] kauditd_printk_skb: 1 callbacks suppressed [ 44.951890] audit: type=1400 audit(1569057640.759:35): avc: denied { map } for pid=7507 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 '10.128.1.18' (ECDSA) to the list of known hosts. executing program [ 51.520867] audit: type=1400 audit(1569057647.329:36): avc: denied { map } for pid=7519 comm="syz-executor768" path="/root/syz-executor768568962" 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 [ 51.551633] ================================================================== [ 51.559228] BUG: KASAN: use-after-free in wait_consider_task+0x1b51/0x3910 [ 51.566369] Read of size 4 at addr ffff888079c46a2c by task sshd/7517 [ 51.573086] [ 51.574864] CPU: 0 PID: 7517 Comm: sshd Not tainted 4.19.75 #0 [ 51.581013] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 51.590407] Call Trace: [ 51.593178] dump_stack+0x172/0x1f0 [ 51.596880] ? wait_consider_task+0x1b51/0x3910 [ 51.601559] print_address_description.cold+0x7c/0x20d [ 51.606852] ? wait_consider_task+0x1b51/0x3910 [ 51.611579] kasan_report.cold+0x8c/0x2ba [ 51.615818] __asan_report_load4_noabort+0x14/0x20 [ 51.620745] wait_consider_task+0x1b51/0x3910 [ 51.625336] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 51.630448] ? add_wait_queue+0x112/0x170 [ 51.634887] ? release_task+0x1630/0x1630 [ 51.639325] ? lock_acquire+0x16f/0x3f0 [ 51.643347] ? do_wait+0x3aa/0x9d0 [ 51.646983] ? kasan_check_write+0x14/0x20 [ 51.651322] do_wait+0x439/0x9d0 [ 51.654689] ? wait_consider_task+0x3910/0x3910 [ 51.659577] ? mark_held_locks+0x100/0x100 [ 51.663810] kernel_wait4+0x171/0x290 [ 51.667610] ? __ia32_sys_waitid+0x140/0x140 [ 51.672016] ? task_stopped_code+0x180/0x180 [ 51.676427] __do_sys_wait4+0x147/0x160 [ 51.680482] ? kernel_wait4+0x290/0x290 [ 51.684461] ? kasan_check_read+0x11/0x20 [ 51.688654] ? _copy_to_user+0xc9/0x120 [ 51.692631] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 51.698707] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 51.703891] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 51.708843] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 51.713598] ? do_syscall_64+0x26/0x620 [ 51.717870] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.723314] ? do_syscall_64+0x26/0x620 [ 51.727462] __x64_sys_wait4+0x97/0xf0 [ 51.731349] do_syscall_64+0xfd/0x620 [ 51.735155] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.740579] RIP: 0033:0x7fc14febba3e [ 51.744376] 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 [ 51.763592] RSP: 002b:00007ffdae8963d0 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 51.771305] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc14febba3e [ 51.778668] RDX: 0000000000000001 RSI: 00007ffdae89640c RDI: ffffffffffffffff [ 51.785935] RBP: 0000555a7ecefc88 R08: 00007ffdae8964d0 R09: 0101010101010101 [ 51.793197] R10: 0000000000000000 R11: 0000000000000246 R12: 0000555a8085ec00 [ 51.800470] R13: 0000555a7ecedfb4 R14: 0000000000000028 R15: 0000555a7ecefca0 [ 51.807832] [ 51.809450] Allocated by task 7517: [ 51.813134] save_stack+0x45/0xd0 [ 51.816584] kasan_kmalloc+0xce/0xf0 [ 51.820294] kasan_slab_alloc+0xf/0x20 [ 51.824173] kmem_cache_alloc_node+0x144/0x710 [ 51.828752] copy_process.part.0+0x1ce0/0x7a30 [ 51.833357] _do_fork+0x257/0xfd0 [ 51.836876] __x64_sys_clone+0xbf/0x150 [ 51.840852] do_syscall_64+0xfd/0x620 [ 51.844648] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.849960] [ 51.851588] Freed by task 0: [ 51.854618] save_stack+0x45/0xd0 [ 51.858235] __kasan_slab_free+0x102/0x150 [ 51.863128] kasan_slab_free+0xe/0x10 [ 51.866930] kmem_cache_free+0x86/0x260 [ 51.870901] free_task+0xdd/0x120 [ 51.874346] __put_task_struct+0x20f/0x4c0 [ 51.878578] finish_task_switch+0x52b/0x780 [ 51.882897] __schedule+0x86e/0x1dc0 [ 51.886612] schedule_idle+0x58/0x80 [ 51.890362] do_idle+0x192/0x560 [ 51.893726] cpu_startup_entry+0xc8/0xe0 [ 51.897784] start_secondary+0x3e8/0x5b0 [ 51.901877] secondary_startup_64+0xa4/0xb0 [ 51.906339] [ 51.908067] The buggy address belongs to the object at ffff888079c465c0 [ 51.908067] which belongs to the cache task_struct of size 6080 [ 51.920922] The buggy address is located 1132 bytes inside of [ 51.920922] 6080-byte region [ffff888079c465c0, ffff888079c47d80) [ 51.934145] The buggy address belongs to the page: [ 51.939497] page:ffffea0001e71180 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 [ 51.949740] flags: 0x1fffc0000008100(slab|head) [ 51.954410] raw: 01fffc0000008100 ffffea0001e70b08 ffffea00023a8388 ffff88812c26d800 [ 51.962568] raw: 0000000000000000 ffff888079c465c0 0000000100000001 0000000000000000 [ 51.970531] page dumped because: kasan: bad access detected [ 51.976233] [ 51.977852] Memory state around the buggy address: [ 51.982774] ffff888079c46900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 51.990131] ffff888079c46980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 51.997486] >ffff888079c46a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 52.004836] ^ [ 52.009642] ffff888079c46a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 52.017096] ffff888079c46b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 52.024483] ================================================================== [ 52.031836] Disabling lock debugging due to kernel taint [ 52.037705] Kernel panic - not syncing: panic_on_warn set ... [ 52.037705] [ 52.045283] CPU: 0 PID: 7517 Comm: sshd Tainted: G B 4.19.75 #0 [ 52.052681] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 52.062124] Call Trace: [ 52.064731] dump_stack+0x172/0x1f0 [ 52.068456] ? wait_consider_task+0x1b51/0x3910 [ 52.073208] panic+0x263/0x507 [ 52.076400] ? __warn_printk+0xf3/0xf3 [ 52.080283] ? retint_kernel+0x2d/0x2d [ 52.084411] ? trace_hardirqs_on+0x5e/0x220 [ 52.088852] ? wait_consider_task+0x1b51/0x3910 [ 52.093553] kasan_end_report+0x47/0x4f [ 52.097525] kasan_report.cold+0xa9/0x2ba [ 52.101670] __asan_report_load4_noabort+0x14/0x20 [ 52.106594] wait_consider_task+0x1b51/0x3910 [ 52.111270] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 52.116571] ? add_wait_queue+0x112/0x170 [ 52.120725] ? release_task+0x1630/0x1630 [ 52.124994] ? lock_acquire+0x16f/0x3f0 [ 52.129474] ? do_wait+0x3aa/0x9d0 [ 52.133025] ? kasan_check_write+0x14/0x20 [ 52.137349] do_wait+0x439/0x9d0 [ 52.140723] ? wait_consider_task+0x3910/0x3910 [ 52.145484] ? mark_held_locks+0x100/0x100 [ 52.149851] kernel_wait4+0x171/0x290 [ 52.153647] ? __ia32_sys_waitid+0x140/0x140 [ 52.158051] ? task_stopped_code+0x180/0x180 [ 52.162453] __do_sys_wait4+0x147/0x160 [ 52.166723] ? kernel_wait4+0x290/0x290 [ 52.170702] ? kasan_check_read+0x11/0x20 [ 52.174845] ? _copy_to_user+0xc9/0x120 [ 52.178826] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 52.184372] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 52.189391] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 52.194387] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 52.199251] ? do_syscall_64+0x26/0x620 [ 52.203231] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 52.208805] ? do_syscall_64+0x26/0x620 [ 52.212869] __x64_sys_wait4+0x97/0xf0 [ 52.217034] do_syscall_64+0xfd/0x620 [ 52.221109] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 52.226293] RIP: 0033:0x7fc14febba3e [ 52.230145] 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 [ 52.249246] RSP: 002b:00007ffdae8963d0 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 52.257169] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc14febba3e [ 52.264499] RDX: 0000000000000001 RSI: 00007ffdae89640c RDI: ffffffffffffffff [ 52.271767] RBP: 0000555a7ecefc88 R08: 00007ffdae8964d0 R09: 0101010101010101 [ 52.279132] R10: 0000000000000000 R11: 0000000000000246 R12: 0000555a8085ec00 [ 52.286595] R13: 0000555a7ecedfb4 R14: 0000000000000028 R15: 0000555a7ecefca0 [ 52.295784] Kernel Offset: disabled [ 52.299767] Rebooting in 86400 seconds..