[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. Starting mcstransd: [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [ 37.051523] audit: type=1800 audit(1569229597.238:33): pid=7307 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 [ 37.073127] audit: type=1800 audit(1569229597.238:34): pid=7307 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: [ 40.786802] audit: type=1400 audit(1569229600.968:35): avc: denied { map } for pid=7484 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 '10.128.0.133' (ECDSA) to the list of known hosts. executing program [ 47.218792] audit: type=1400 audit(1569229607.398:36): avc: denied { map } for pid=7496 comm="syz-executor168" path="/root/syz-executor168259032" 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 [ 47.243758] ================================================================== [ 47.252494] BUG: KASAN: use-after-free in wait_consider_task+0x1b51/0x3910 [ 47.259502] Read of size 4 at addr ffff8880934a08ac by task syz-executor168/7496 [ 47.267011] [ 47.268628] CPU: 0 PID: 7496 Comm: syz-executor168 Not tainted 4.19.75 #0 [ 47.275531] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 47.284865] Call Trace: [ 47.287440] dump_stack+0x172/0x1f0 [ 47.291053] ? wait_consider_task+0x1b51/0x3910 [ 47.295705] print_address_description.cold+0x7c/0x20d [ 47.300965] ? wait_consider_task+0x1b51/0x3910 [ 47.305628] kasan_report.cold+0x8c/0x2ba [ 47.309760] __asan_report_load4_noabort+0x14/0x20 [ 47.314681] wait_consider_task+0x1b51/0x3910 [ 47.319159] ? lockdep_hardirqs_on+0x415/0x5d0 [ 47.323724] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 47.328806] ? add_wait_queue+0x112/0x170 [ 47.332937] ? release_task+0x1630/0x1630 [ 47.337063] ? lock_acquire+0x16f/0x3f0 [ 47.341027] ? do_wait+0x3aa/0x9d0 [ 47.344550] ? kasan_check_write+0x14/0x20 [ 47.348769] do_wait+0x439/0x9d0 [ 47.352121] ? wait_consider_task+0x3910/0x3910 [ 47.356774] kernel_wait4+0x171/0x290 [ 47.360569] ? __ia32_sys_waitid+0x140/0x140 [ 47.364960] ? task_stopped_code+0x180/0x180 [ 47.369357] __do_sys_wait4+0x147/0x160 [ 47.373324] ? kernel_wait4+0x290/0x290 [ 47.377278] ? _copy_to_user+0xc9/0x120 [ 47.381249] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 47.386766] ? put_timespec64+0xda/0x140 [ 47.390809] ? nsecs_to_jiffies+0x30/0x30 [ 47.394944] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 47.399680] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 47.404413] ? do_syscall_64+0x26/0x620 [ 47.408381] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 47.413725] ? do_syscall_64+0x26/0x620 [ 47.417684] __x64_sys_wait4+0x97/0xf0 [ 47.421554] do_syscall_64+0xfd/0x620 [ 47.425339] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 47.430507] RIP: 0033:0x4011aa [ 47.433680] Code: c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 8b 05 4e 15 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 [ 47.452572] RSP: 002b:00007fff5c5616d8 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 47.460264] RAX: ffffffffffffffda RBX: 0000000000001d49 RCX: 00000000004011aa [ 47.467515] RDX: 0000000040000001 RSI: 00007fff5c5616e4 RDI: ffffffffffffffff [ 47.474766] RBP: 000000000000b85a R08: 0000000000000000 R09: 00005555561a6880 [ 47.482017] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402160 [ 47.489281] R13: 00000000004021f0 R14: 0000000000000000 R15: 0000000000000000 [ 47.496548] [ 47.498155] Allocated by task 7496: [ 47.501769] save_stack+0x45/0xd0 [ 47.505201] kasan_kmalloc+0xce/0xf0 [ 47.508894] kasan_slab_alloc+0xf/0x20 [ 47.512766] kmem_cache_alloc_node+0x144/0x710 [ 47.517327] copy_process.part.0+0x1ce0/0x7a30 [ 47.521887] _do_fork+0x257/0xfd0 [ 47.525318] __x64_sys_clone+0xbf/0x150 [ 47.529272] do_syscall_64+0xfd/0x620 [ 47.533053] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 47.538215] [ 47.539822] Freed by task 0: [ 47.542823] save_stack+0x45/0xd0 [ 47.546257] __kasan_slab_free+0x102/0x150 [ 47.550481] kasan_slab_free+0xe/0x10 [ 47.554260] kmem_cache_free+0x86/0x260 [ 47.558220] free_task+0xdd/0x120 [ 47.561651] __put_task_struct+0x20f/0x4c0 [ 47.565863] finish_task_switch+0x52b/0x780 [ 47.570177] __schedule+0x86e/0x1dc0 [ 47.573870] schedule_idle+0x58/0x80 [ 47.577563] do_idle+0x192/0x560 [ 47.580910] cpu_startup_entry+0xc8/0xe0 [ 47.584961] rest_init+0x219/0x222 [ 47.588480] start_kernel+0x88c/0x8c5 [ 47.592262] x86_64_start_reservations+0x29/0x2b [ 47.597000] x86_64_start_kernel+0x77/0x7b [ 47.601214] secondary_startup_64+0xa4/0xb0 [ 47.605508] [ 47.607126] The buggy address belongs to the object at ffff8880934a0440 [ 47.607126] which belongs to the cache task_struct of size 6080 [ 47.619849] The buggy address is located 1132 bytes inside of [ 47.619849] 6080-byte region [ffff8880934a0440, ffff8880934a1c00) [ 47.631874] The buggy address belongs to the page: [ 47.636784] page:ffffea00024d2800 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 [ 47.646731] flags: 0x1fffc0000008100(slab|head) [ 47.651383] raw: 01fffc0000008100 ffffea0002184908 ffffea0002839288 ffff88812c26d800 [ 47.659244] raw: 0000000000000000 ffff8880934a0440 0000000100000001 0000000000000000 [ 47.667187] page dumped because: kasan: bad access detected [ 47.672977] [ 47.674585] Memory state around the buggy address: [ 47.679503] ffff8880934a0780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.686848] ffff8880934a0800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.694191] >ffff8880934a0880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.701532] ^ [ 47.706185] ffff8880934a0900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.713583] ffff8880934a0980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.720918] ================================================================== [ 47.728255] Disabling lock debugging due to kernel taint [ 47.733855] Kernel panic - not syncing: panic_on_warn set ... [ 47.733855] [ 47.741221] CPU: 0 PID: 7496 Comm: syz-executor168 Tainted: G B 4.19.75 #0 [ 47.749512] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 47.758867] Call Trace: [ 47.761441] dump_stack+0x172/0x1f0 [ 47.765051] ? wait_consider_task+0x1b51/0x3910 [ 47.769698] panic+0x263/0x507 [ 47.772868] ? __warn_printk+0xf3/0xf3 [ 47.776733] ? retint_kernel+0x2d/0x2d [ 47.780604] ? trace_hardirqs_on+0x5e/0x220 [ 47.784909] ? wait_consider_task+0x1b51/0x3910 [ 47.789560] kasan_end_report+0x47/0x4f [ 47.793517] kasan_report.cold+0xa9/0x2ba [ 47.797658] __asan_report_load4_noabort+0x14/0x20 [ 47.802569] wait_consider_task+0x1b51/0x3910 [ 47.807044] ? lockdep_hardirqs_on+0x415/0x5d0 [ 47.811608] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 47.816689] ? add_wait_queue+0x112/0x170 [ 47.820820] ? release_task+0x1630/0x1630 [ 47.824945] ? lock_acquire+0x16f/0x3f0 [ 47.828897] ? do_wait+0x3aa/0x9d0 [ 47.832422] ? kasan_check_write+0x14/0x20 [ 47.836635] do_wait+0x439/0x9d0 [ 47.839994] ? wait_consider_task+0x3910/0x3910 [ 47.844645] kernel_wait4+0x171/0x290 [ 47.848428] ? __ia32_sys_waitid+0x140/0x140 [ 47.852818] ? task_stopped_code+0x180/0x180 [ 47.857211] __do_sys_wait4+0x147/0x160 [ 47.861182] ? kernel_wait4+0x290/0x290 [ 47.865144] ? _copy_to_user+0xc9/0x120 [ 47.869099] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 47.874623] ? put_timespec64+0xda/0x140 [ 47.878660] ? nsecs_to_jiffies+0x30/0x30 [ 47.882790] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 47.887531] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 47.892267] ? do_syscall_64+0x26/0x620 [ 47.896221] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 47.901573] ? do_syscall_64+0x26/0x620 [ 47.905528] __x64_sys_wait4+0x97/0xf0 [ 47.909398] do_syscall_64+0xfd/0x620 [ 47.913185] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 47.918355] RIP: 0033:0x4011aa [ 47.921528] Code: c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 8b 05 4e 15 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 [ 47.940409] RSP: 002b:00007fff5c5616d8 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 47.948117] RAX: ffffffffffffffda RBX: 0000000000001d49 RCX: 00000000004011aa [ 47.955369] RDX: 0000000040000001 RSI: 00007fff5c5616e4 RDI: ffffffffffffffff [ 47.962627] RBP: 000000000000b85a R08: 0000000000000000 R09: 00005555561a6880 [ 47.969895] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402160 [ 47.977143] R13: 00000000004021f0 R14: 0000000000000000 R15: 0000000000000000 [ 47.985629] Kernel Offset: disabled [ 47.989274] Rebooting in 86400 seconds..