[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [ 35.251051] kauditd_printk_skb: 9 callbacks suppressed [ 35.251061] audit: type=1800 audit(1569097921.324:33): pid=7141 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 [ 35.278582] audit: type=1800 audit(1569097921.324:34): pid=7141 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: [ 41.615922] audit: type=1400 audit(1569097927.694:35): avc: denied { map } for pid=7317 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 '10.128.1.60' (ECDSA) to the list of known hosts. executing program [ 48.054580] audit: type=1400 audit(1569097934.134:36): avc: denied { map } for pid=7329 comm="syz-executor422" path="/root/syz-executor422878880" dev="sda1" ino=16484 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 [ 48.087839] ================================================================== [ 48.095252] BUG: KASAN: use-after-free in wait_consider_task+0x1b51/0x3910 [ 48.102243] Read of size 4 at addr ffff88808620c8ec by task syz-executor422/7329 [ 48.109748] [ 48.111370] CPU: 0 PID: 7329 Comm: syz-executor422 Not tainted 4.19.75 #0 [ 48.118299] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 48.127646] Call Trace: [ 48.130214] dump_stack+0x172/0x1f0 [ 48.133826] ? wait_consider_task+0x1b51/0x3910 [ 48.138473] print_address_description.cold+0x7c/0x20d [ 48.143743] ? wait_consider_task+0x1b51/0x3910 [ 48.148391] kasan_report.cold+0x8c/0x2ba [ 48.152536] __asan_report_load4_noabort+0x14/0x20 [ 48.157446] wait_consider_task+0x1b51/0x3910 [ 48.161932] ? lockdep_hardirqs_on+0x415/0x5d0 [ 48.166496] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 48.171578] ? add_wait_queue+0x112/0x170 [ 48.175703] ? release_task+0x1630/0x1630 [ 48.179827] ? lock_acquire+0x16f/0x3f0 [ 48.183794] ? do_wait+0x3aa/0x9d0 [ 48.187331] ? kasan_check_write+0x14/0x20 [ 48.191557] do_wait+0x439/0x9d0 [ 48.194907] ? wait_consider_task+0x3910/0x3910 [ 48.199556] kernel_wait4+0x171/0x290 [ 48.203335] ? __ia32_sys_waitid+0x140/0x140 [ 48.207726] ? task_stopped_code+0x180/0x180 [ 48.212118] __do_sys_wait4+0x147/0x160 [ 48.216068] ? kernel_wait4+0x290/0x290 [ 48.220027] ? _copy_to_user+0xc9/0x120 [ 48.223981] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 48.229498] ? put_timespec64+0xda/0x140 [ 48.233536] ? nsecs_to_jiffies+0x30/0x30 [ 48.237674] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 48.242411] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 48.247145] ? do_syscall_64+0x26/0x620 [ 48.251094] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.256432] ? do_syscall_64+0x26/0x620 [ 48.260387] __x64_sys_wait4+0x97/0xf0 [ 48.264283] do_syscall_64+0xfd/0x620 [ 48.268065] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.273230] RIP: 0033:0x4012fa [ 48.276402] Code: c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 8b 05 fe 13 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 [ 48.295280] RSP: 002b:00007fff2b5b3468 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 48.302999] RAX: ffffffffffffffda RBX: 0000000000001ca2 RCX: 00000000004012fa [ 48.310246] RDX: 0000000040000001 RSI: 00007fff2b5b3474 RDI: ffffffffffffffff [ 48.317494] RBP: 000000000000bb9d R08: 0000000000000000 R09: 000055555569a880 [ 48.324748] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004022b0 [ 48.331994] R13: 0000000000402340 R14: 0000000000000000 R15: 0000000000000000 [ 48.339249] [ 48.340853] Allocated by task 7329: [ 48.344463] save_stack+0x45/0xd0 [ 48.347896] kasan_kmalloc+0xce/0xf0 [ 48.351586] kasan_slab_alloc+0xf/0x20 [ 48.355466] kmem_cache_alloc_node+0x144/0x710 [ 48.360158] copy_process.part.0+0x1ce0/0x7a30 [ 48.364723] _do_fork+0x257/0xfd0 [ 48.368153] __x64_sys_clone+0xbf/0x150 [ 48.372109] do_syscall_64+0xfd/0x620 [ 48.375893] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.381055] [ 48.382704] Freed by task 3221: [ 48.385963] save_stack+0x45/0xd0 [ 48.389410] __kasan_slab_free+0x102/0x150 [ 48.393625] kasan_slab_free+0xe/0x10 [ 48.397405] kmem_cache_free+0x86/0x260 [ 48.401362] free_task+0xdd/0x120 [ 48.404792] __put_task_struct+0x20f/0x4c0 [ 48.409035] finish_task_switch+0x52b/0x780 [ 48.413336] __schedule+0x86e/0x1dc0 [ 48.417035] schedule+0x92/0x1c0 [ 48.420384] worker_thread+0x248/0xe40 [ 48.424254] kthread+0x354/0x420 [ 48.427597] ret_from_fork+0x24/0x30 [ 48.431285] [ 48.432895] The buggy address belongs to the object at ffff88808620c480 [ 48.432895] which belongs to the cache task_struct of size 6080 [ 48.445617] The buggy address is located 1132 bytes inside of [ 48.445617] 6080-byte region [ffff88808620c480, ffff88808620dc40) [ 48.457645] The buggy address belongs to the page: [ 48.462558] page:ffffea0002188300 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 [ 48.472513] flags: 0x1fffc0000008100(slab|head) [ 48.477173] raw: 01fffc0000008100 ffffea0002708588 ffffea0002152688 ffff88812c26d800 [ 48.485035] raw: 0000000000000000 ffff88808620c480 0000000100000001 0000000000000000 [ 48.492891] page dumped because: kasan: bad access detected [ 48.498574] [ 48.500178] Memory state around the buggy address: [ 48.505086] ffff88808620c780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.512432] ffff88808620c800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.519784] >ffff88808620c880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.527118] ^ [ 48.533847] ffff88808620c900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.541182] ffff88808620c980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.548523] ================================================================== [ 48.555874] Disabling lock debugging due to kernel taint [ 48.561486] Kernel panic - not syncing: panic_on_warn set ... [ 48.561486] [ 48.568848] CPU: 0 PID: 7329 Comm: syz-executor422 Tainted: G B 4.19.75 #0 [ 48.577137] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 48.586467] Call Trace: [ 48.589033] dump_stack+0x172/0x1f0 [ 48.592641] ? wait_consider_task+0x1b51/0x3910 [ 48.597293] panic+0x263/0x507 [ 48.600461] ? __warn_printk+0xf3/0xf3 [ 48.604325] ? retint_kernel+0x2d/0x2d [ 48.608194] ? trace_hardirqs_on+0x5e/0x220 [ 48.612514] ? wait_consider_task+0x1b51/0x3910 [ 48.617169] kasan_end_report+0x47/0x4f [ 48.621131] kasan_report.cold+0xa9/0x2ba [ 48.625259] __asan_report_load4_noabort+0x14/0x20 [ 48.630165] wait_consider_task+0x1b51/0x3910 [ 48.634665] ? lockdep_hardirqs_on+0x415/0x5d0 [ 48.639230] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 48.644310] ? add_wait_queue+0x112/0x170 [ 48.648435] ? release_task+0x1630/0x1630 [ 48.652564] ? lock_acquire+0x16f/0x3f0 [ 48.656519] ? do_wait+0x3aa/0x9d0 [ 48.660037] ? kasan_check_write+0x14/0x20 [ 48.664249] do_wait+0x439/0x9d0 [ 48.667595] ? wait_consider_task+0x3910/0x3910 [ 48.672244] kernel_wait4+0x171/0x290 [ 48.676031] ? __ia32_sys_waitid+0x140/0x140 [ 48.680418] ? task_stopped_code+0x180/0x180 [ 48.684817] __do_sys_wait4+0x147/0x160 [ 48.688787] ? kernel_wait4+0x290/0x290 [ 48.692739] ? _copy_to_user+0xc9/0x120 [ 48.696695] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 48.702210] ? put_timespec64+0xda/0x140 [ 48.706255] ? nsecs_to_jiffies+0x30/0x30 [ 48.710386] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 48.715120] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 48.719854] ? do_syscall_64+0x26/0x620 [ 48.723806] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.729143] ? do_syscall_64+0x26/0x620 [ 48.733099] __x64_sys_wait4+0x97/0xf0 [ 48.736963] do_syscall_64+0xfd/0x620 [ 48.740740] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.745911] RIP: 0033:0x4012fa [ 48.749090] Code: c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 8b 05 fe 13 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 [ 48.767967] RSP: 002b:00007fff2b5b3468 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 48.775658] RAX: ffffffffffffffda RBX: 0000000000001ca2 RCX: 00000000004012fa [ 48.782908] RDX: 0000000040000001 RSI: 00007fff2b5b3474 RDI: ffffffffffffffff [ 48.790153] RBP: 000000000000bb9d R08: 0000000000000000 R09: 000055555569a880 [ 48.797406] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004022b0 [ 48.804654] R13: 0000000000402340 R14: 0000000000000000 R15: 0000000000000000 [ 48.813111] Kernel Offset: disabled [ 48.816733] Rebooting in 86400 seconds..