[ 39.029867] audit: type=1800 audit(1569494852.742:32): pid=7391 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 mcstransd: [....] 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. [ 39.756117] audit: type=1800 audit(1569494853.572:33): pid=7391 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 '10.128.0.118' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 50.281358] kauditd_printk_skb: 2 callbacks suppressed [ 50.281373] audit: type=1400 audit(1569494864.092:36): avc: denied { map } for pid=7579 comm="syz-executor753" path="/root/syz-executor753966788" 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 [ 50.321507] ================================================================== [ 50.329351] BUG: KASAN: use-after-free in wait_consider_task+0x1b51/0x3910 [ 50.336352] Read of size 4 at addr ffff88809acbe92c by task sshd/7577 [ 50.343042] [ 50.344691] CPU: 1 PID: 7577 Comm: sshd Not tainted 4.19.75 #0 [ 50.350930] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 50.360377] Call Trace: [ 50.362986] dump_stack+0x172/0x1f0 [ 50.366618] ? wait_consider_task+0x1b51/0x3910 [ 50.371282] print_address_description.cold+0x7c/0x20d [ 50.377346] ? wait_consider_task+0x1b51/0x3910 [ 50.382004] kasan_report.cold+0x8c/0x2ba [ 50.386143] __asan_report_load4_noabort+0x14/0x20 [ 50.391058] wait_consider_task+0x1b51/0x3910 [ 50.395542] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 50.400629] ? add_wait_queue+0x112/0x170 [ 50.404766] ? release_task+0x1630/0x1630 [ 50.408905] ? lock_acquire+0x16f/0x3f0 [ 50.413149] ? do_wait+0x3aa/0x9d0 [ 50.416696] ? kasan_check_write+0x14/0x20 [ 50.420922] do_wait+0x439/0x9d0 [ 50.424292] ? wait_consider_task+0x3910/0x3910 [ 50.429081] ? mark_held_locks+0x100/0x100 [ 50.433309] kernel_wait4+0x171/0x290 [ 50.437126] ? __ia32_sys_waitid+0x140/0x140 [ 50.441525] ? task_stopped_code+0x180/0x180 [ 50.445925] __do_sys_wait4+0x147/0x160 [ 50.449889] ? kernel_wait4+0x290/0x290 [ 50.453860] ? kasan_check_read+0x11/0x20 [ 50.457999] ? _copy_to_user+0xc9/0x120 [ 50.461975] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 50.467506] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 50.472521] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 50.477263] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 50.482044] ? do_syscall_64+0x26/0x620 [ 50.486027] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 50.491623] ? do_syscall_64+0x26/0x620 [ 50.495778] __x64_sys_wait4+0x97/0xf0 [ 50.499664] do_syscall_64+0xfd/0x620 [ 50.503467] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 50.508662] RIP: 0033:0x7f9ef468ba3e [ 50.512371] 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 [ 50.531354] RSP: 002b:00007ffc4b12d700 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 50.539051] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f9ef468ba3e [ 50.546333] RDX: 0000000000000001 RSI: 00007ffc4b12d73c RDI: ffffffffffffffff [ 50.553600] RBP: 0000561a7bd15c88 R08: 00007ffc4b12d800 R09: 0101010101010101 [ 50.560983] R10: 0000000000000000 R11: 0000000000000246 R12: 0000561a7dd0dae0 [ 50.569197] R13: 0000561a7bd13fb4 R14: 0000000000000028 R15: 0000561a7bd15ca0 [ 50.576462] [ 50.578095] Allocated by task 7577: [ 50.581724] save_stack+0x45/0xd0 [ 50.585163] kasan_kmalloc+0xce/0xf0 [ 50.588864] kasan_slab_alloc+0xf/0x20 [ 50.592744] kmem_cache_alloc_node+0x144/0x710 [ 50.597323] copy_process.part.0+0x1ce0/0x7a30 [ 50.601899] _do_fork+0x257/0xfd0 [ 50.605422] __x64_sys_clone+0xbf/0x150 [ 50.609562] do_syscall_64+0xfd/0x620 [ 50.613522] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 50.618696] [ 50.620306] Freed by task 0: [ 50.623313] save_stack+0x45/0xd0 [ 50.626750] __kasan_slab_free+0x102/0x150 [ 50.630986] kasan_slab_free+0xe/0x10 [ 50.634770] kmem_cache_free+0x86/0x260 [ 50.638751] free_task+0xdd/0x120 [ 50.642209] __put_task_struct+0x20f/0x4c0 [ 50.646441] finish_task_switch+0x52b/0x780 [ 50.650759] __schedule+0x86e/0x1dc0 [ 50.654471] schedule_idle+0x58/0x80 [ 50.658178] do_idle+0x192/0x560 [ 50.661528] cpu_startup_entry+0xc8/0xe0 [ 50.665572] rest_init+0x219/0x222 [ 50.669097] start_kernel+0x88c/0x8c5 [ 50.672903] x86_64_start_reservations+0x29/0x2b [ 50.677646] x86_64_start_kernel+0x77/0x7b [ 50.681876] secondary_startup_64+0xa4/0xb0 [ 50.686182] [ 50.687857] The buggy address belongs to the object at ffff88809acbe4c0 [ 50.687857] which belongs to the cache task_struct of size 6080 [ 50.700603] The buggy address is located 1132 bytes inside of [ 50.700603] 6080-byte region [ffff88809acbe4c0, ffff88809acbfc80) [ 50.712813] The buggy address belongs to the page: [ 50.717731] page:ffffea00026b2f80 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 [ 50.727688] flags: 0x1fffc0000008100(slab|head) [ 50.732344] raw: 01fffc0000008100 ffffea00026d8508 ffffea0002803d88 ffff88812c26d800 [ 50.740226] raw: 0000000000000000 ffff88809acbe4c0 0000000100000001 0000000000000000 [ 50.749094] page dumped because: kasan: bad access detected [ 50.754792] [ 50.756663] Memory state around the buggy address: [ 50.761596] ffff88809acbe800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 50.769668] ffff88809acbe880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 50.777106] >ffff88809acbe900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 50.784637] ^ [ 50.789289] ffff88809acbe980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 50.796635] ffff88809acbea00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 50.804069] ================================================================== [ 50.811414] Disabling lock debugging due to kernel taint [ 50.816997] Kernel panic - not syncing: panic_on_warn set ... [ 50.816997] [ 50.824376] CPU: 1 PID: 7577 Comm: sshd Tainted: G B 4.19.75 #0 [ 50.831899] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 50.841240] Call Trace: [ 50.843820] dump_stack+0x172/0x1f0 [ 50.847438] ? wait_consider_task+0x1b51/0x3910 [ 50.852175] panic+0x263/0x507 [ 50.855723] ? __warn_printk+0xf3/0xf3 [ 50.859621] ? retint_kernel+0x2d/0x2d [ 50.863511] ? trace_hardirqs_on+0x5e/0x220 [ 50.867840] ? wait_consider_task+0x1b51/0x3910 [ 50.872495] kasan_end_report+0x47/0x4f [ 50.876543] kasan_report.cold+0xa9/0x2ba [ 50.880702] __asan_report_load4_noabort+0x14/0x20 [ 50.885627] wait_consider_task+0x1b51/0x3910 [ 50.890125] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 50.895319] ? add_wait_queue+0x112/0x170 [ 50.899474] ? release_task+0x1630/0x1630 [ 50.903614] ? lock_acquire+0x16f/0x3f0 [ 50.907578] ? do_wait+0x3aa/0x9d0 [ 50.911104] ? kasan_check_write+0x14/0x20 [ 50.915320] do_wait+0x439/0x9d0 [ 50.918672] ? wait_consider_task+0x3910/0x3910 [ 50.923341] ? mark_held_locks+0x100/0x100 [ 50.928006] kernel_wait4+0x171/0x290 [ 50.931823] ? __ia32_sys_waitid+0x140/0x140 [ 50.936324] ? task_stopped_code+0x180/0x180 [ 50.940730] __do_sys_wait4+0x147/0x160 [ 50.944694] ? kernel_wait4+0x290/0x290 [ 50.948776] ? kasan_check_read+0x11/0x20 [ 50.952931] ? _copy_to_user+0xc9/0x120 [ 50.957254] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 50.962780] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 50.967784] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 50.973494] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 50.978238] ? do_syscall_64+0x26/0x620 [ 50.982219] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 50.987757] ? do_syscall_64+0x26/0x620 [ 50.991826] __x64_sys_wait4+0x97/0xf0 [ 50.995809] do_syscall_64+0xfd/0x620 [ 50.999597] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.004784] RIP: 0033:0x7f9ef468ba3e [ 51.008509] 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 [ 51.027662] RSP: 002b:00007ffc4b12d700 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 51.035452] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f9ef468ba3e [ 51.042707] RDX: 0000000000000001 RSI: 00007ffc4b12d73c RDI: ffffffffffffffff [ 51.050056] RBP: 0000561a7bd15c88 R08: 00007ffc4b12d800 R09: 0101010101010101 [ 51.057320] R10: 0000000000000000 R11: 0000000000000246 R12: 0000561a7dd0dae0 [ 51.064592] R13: 0000561a7bd13fb4 R14: 0000000000000028 R15: 0000561a7bd15ca0 [ 51.073235] Kernel Offset: disabled [ 51.076872] Rebooting in 86400 seconds..