[....] 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. [ 36.606214] audit: type=1800 audit(1569100339.527:33): pid=7281 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 [ 36.632737] audit: type=1800 audit(1569100339.527:34): pid=7281 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: [ 40.665299] audit: type=1400 audit(1569100343.577:35): avc: denied { map } for pid=7457 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 '10.128.0.217' (ECDSA) to the list of known hosts. executing program [ 47.106135] audit: type=1400 audit(1569100350.017:36): avc: denied { map } for pid=7470 comm="syz-executor130" path="/root/syz-executor130702833" 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 [ 47.144468] ================================================================== [ 47.152711] BUG: KASAN: use-after-free in wait_consider_task+0x1b51/0x3910 [ 47.159822] Read of size 4 at addr ffff88808ffda72c by task sshd/7468 [ 47.166382] [ 47.167999] CPU: 1 PID: 7468 Comm: sshd Not tainted 4.19.75 #0 [ 47.173993] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 47.183331] Call Trace: [ 47.185907] dump_stack+0x172/0x1f0 [ 47.189619] ? wait_consider_task+0x1b51/0x3910 [ 47.194279] print_address_description.cold+0x7c/0x20d [ 47.199561] ? wait_consider_task+0x1b51/0x3910 [ 47.204215] kasan_report.cold+0x8c/0x2ba [ 47.208351] __asan_report_load4_noabort+0x14/0x20 [ 47.213266] wait_consider_task+0x1b51/0x3910 [ 47.217764] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 47.222871] ? add_wait_queue+0x112/0x170 [ 47.227020] ? release_task+0x1630/0x1630 [ 47.231163] ? lock_acquire+0x16f/0x3f0 [ 47.235127] ? do_wait+0x3aa/0x9d0 [ 47.238675] ? kasan_check_write+0x14/0x20 [ 47.242898] do_wait+0x439/0x9d0 [ 47.246253] ? wait_consider_task+0x3910/0x3910 [ 47.250913] ? mark_held_locks+0x100/0x100 [ 47.255150] kernel_wait4+0x171/0x290 [ 47.258984] ? __ia32_sys_waitid+0x140/0x140 [ 47.263386] ? task_stopped_code+0x180/0x180 [ 47.267793] __do_sys_wait4+0x147/0x160 [ 47.271769] ? kernel_wait4+0x290/0x290 [ 47.275733] ? kasan_check_read+0x11/0x20 [ 47.279867] ? _copy_to_user+0xc9/0x120 [ 47.283853] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 47.289375] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 47.294379] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 47.299154] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 47.303907] ? do_syscall_64+0x26/0x620 [ 47.307868] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 47.313216] ? do_syscall_64+0x26/0x620 [ 47.317191] __x64_sys_wait4+0x97/0xf0 [ 47.321073] do_syscall_64+0xfd/0x620 [ 47.324870] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 47.330046] RIP: 0033:0x7ff283ffba3e [ 47.333744] 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 [ 47.352641] RSP: 002b:00007ffeafe45cd0 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 47.360351] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff283ffba3e [ 47.367605] RDX: 0000000000000001 RSI: 00007ffeafe45d0c RDI: ffffffffffffffff [ 47.374857] RBP: 000055b207fc3c88 R08: 00007ffeafe45dd0 R09: 0101010101010101 [ 47.382110] R10: 0000000000000000 R11: 0000000000000246 R12: 000055b20999cc00 [ 47.389374] R13: 000055b207fc1fb4 R14: 0000000000000028 R15: 000055b207fc3ca0 [ 47.396637] [ 47.398262] Allocated by task 7468: [ 47.401875] save_stack+0x45/0xd0 [ 47.405326] kasan_kmalloc+0xce/0xf0 [ 47.409037] kasan_slab_alloc+0xf/0x20 [ 47.412912] kmem_cache_alloc_node+0x144/0x710 [ 47.417482] copy_process.part.0+0x1ce0/0x7a30 [ 47.422066] _do_fork+0x257/0xfd0 [ 47.425512] __x64_sys_clone+0xbf/0x150 [ 47.429482] do_syscall_64+0xfd/0x620 [ 47.433275] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 47.438448] [ 47.440058] Freed by task 0: [ 47.443064] save_stack+0x45/0xd0 [ 47.446500] __kasan_slab_free+0x102/0x150 [ 47.450806] kasan_slab_free+0xe/0x10 [ 47.454595] kmem_cache_free+0x86/0x260 [ 47.458725] free_task+0xdd/0x120 [ 47.462165] __put_task_struct+0x20f/0x4c0 [ 47.466394] finish_task_switch+0x52b/0x780 [ 47.470810] __schedule+0x86e/0x1dc0 [ 47.474508] schedule_idle+0x58/0x80 [ 47.478213] do_idle+0x192/0x560 [ 47.481559] cpu_startup_entry+0xc8/0xe0 [ 47.485611] rest_init+0x219/0x222 [ 47.489140] start_kernel+0x88c/0x8c5 [ 47.492935] x86_64_start_reservations+0x29/0x2b [ 47.497683] x86_64_start_kernel+0x77/0x7b [ 47.501899] secondary_startup_64+0xa4/0xb0 [ 47.506207] [ 47.507816] The buggy address belongs to the object at ffff88808ffda2c0 [ 47.507816] which belongs to the cache task_struct of size 6080 [ 47.520629] The buggy address is located 1132 bytes inside of [ 47.520629] 6080-byte region [ffff88808ffda2c0, ffff88808ffdba80) [ 47.532656] The buggy address belongs to the page: [ 47.537567] page:ffffea00023ff680 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 [ 47.547520] flags: 0x1fffc0000008100(slab|head) [ 47.552172] raw: 01fffc0000008100 ffffea00027c8a88 ffffea00029e9988 ffff88812c26d800 [ 47.560036] raw: 0000000000000000 ffff88808ffda2c0 0000000100000001 0000000000000000 [ 47.567894] page dumped because: kasan: bad access detected [ 47.573580] [ 47.575183] Memory state around the buggy address: [ 47.580105] ffff88808ffda600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.587447] ffff88808ffda680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.594786] >ffff88808ffda700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.602133] ^ [ 47.606785] ffff88808ffda780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.614137] ffff88808ffda800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.621474] ================================================================== [ 47.628811] Disabling lock debugging due to kernel taint [ 47.634429] Kernel panic - not syncing: panic_on_warn set ... [ 47.634429] [ 47.641813] CPU: 1 PID: 7468 Comm: sshd Tainted: G B 4.19.75 #0 [ 47.649167] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 47.658685] Call Trace: [ 47.661256] dump_stack+0x172/0x1f0 [ 47.664879] ? wait_consider_task+0x1b51/0x3910 [ 47.669531] panic+0x263/0x507 [ 47.672704] ? __warn_printk+0xf3/0xf3 [ 47.676578] ? retint_kernel+0x2d/0x2d [ 47.680449] ? trace_hardirqs_on+0x5e/0x220 [ 47.684754] ? wait_consider_task+0x1b51/0x3910 [ 47.689408] kasan_end_report+0x47/0x4f [ 47.693363] kasan_report.cold+0xa9/0x2ba [ 47.697508] __asan_report_load4_noabort+0x14/0x20 [ 47.702420] wait_consider_task+0x1b51/0x3910 [ 47.706916] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 47.712000] ? add_wait_queue+0x112/0x170 [ 47.716128] ? release_task+0x1630/0x1630 [ 47.720255] ? lock_acquire+0x16f/0x3f0 [ 47.724212] ? do_wait+0x3aa/0x9d0 [ 47.727738] ? kasan_check_write+0x14/0x20 [ 47.731969] do_wait+0x439/0x9d0 [ 47.735318] ? wait_consider_task+0x3910/0x3910 [ 47.740004] ? mark_held_locks+0x100/0x100 [ 47.744219] kernel_wait4+0x171/0x290 [ 47.748011] ? __ia32_sys_waitid+0x140/0x140 [ 47.752402] ? task_stopped_code+0x180/0x180 [ 47.756808] __do_sys_wait4+0x147/0x160 [ 47.760761] ? kernel_wait4+0x290/0x290 [ 47.764718] ? kasan_check_read+0x11/0x20 [ 47.768848] ? _copy_to_user+0xc9/0x120 [ 47.772804] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 47.778323] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 47.783319] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 47.788070] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 47.792806] ? do_syscall_64+0x26/0x620 [ 47.796763] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 47.802108] ? do_syscall_64+0x26/0x620 [ 47.806075] __x64_sys_wait4+0x97/0xf0 [ 47.809947] do_syscall_64+0xfd/0x620 [ 47.813729] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 47.818907] RIP: 0033:0x7ff283ffba3e [ 47.822613] 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 [ 47.841770] RSP: 002b:00007ffeafe45cd0 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 47.849471] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff283ffba3e [ 47.856723] RDX: 0000000000000001 RSI: 00007ffeafe45d0c RDI: ffffffffffffffff [ 47.863973] RBP: 000055b207fc3c88 R08: 00007ffeafe45dd0 R09: 0101010101010101 [ 47.871222] R10: 0000000000000000 R11: 0000000000000246 R12: 000055b20999cc00 [ 47.878470] R13: 000055b207fc1fb4 R14: 0000000000000028 R15: 000055b207fc3ca0 [ 47.887451] Kernel Offset: disabled [ 47.891075] Rebooting in 86400 seconds..