[ 38.018737] audit: type=1800 audit(1569113032.315:32): pid=7387 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 OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [ 38.808109] audit: type=1800 audit(1569113033.185:33): pid=7387 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 '10.128.0.120' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 47.719178] kauditd_printk_skb: 2 callbacks suppressed [ 47.719193] audit: type=1400 audit(1569113042.095:36): avc: denied { map } for pid=7575 comm="syz-executor475" path="/root/syz-executor475557976" 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 [ 47.758061] ================================================================== [ 47.765821] BUG: KASAN: use-after-free in wait_consider_task+0x1b51/0x3910 [ 47.772857] Read of size 4 at addr ffff8880858f4b6c by task sshd/7573 [ 47.779456] [ 47.781078] CPU: 1 PID: 7573 Comm: sshd Not tainted 4.19.75 #0 [ 47.787045] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 47.796382] Call Trace: [ 47.798964] dump_stack+0x172/0x1f0 [ 47.802585] ? wait_consider_task+0x1b51/0x3910 [ 47.807250] print_address_description.cold+0x7c/0x20d [ 47.812514] ? wait_consider_task+0x1b51/0x3910 [ 47.817175] kasan_report.cold+0x8c/0x2ba [ 47.821311] __asan_report_load4_noabort+0x14/0x20 [ 47.826241] wait_consider_task+0x1b51/0x3910 [ 47.830731] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 47.835837] ? add_wait_queue+0x112/0x170 [ 47.840009] ? release_task+0x1630/0x1630 [ 47.844166] ? lock_acquire+0x16f/0x3f0 [ 47.848141] ? do_wait+0x3aa/0x9d0 [ 47.851783] ? kasan_check_write+0x14/0x20 [ 47.856024] do_wait+0x439/0x9d0 [ 47.859405] ? wait_consider_task+0x3910/0x3910 [ 47.864082] ? mark_held_locks+0x100/0x100 [ 47.868324] kernel_wait4+0x171/0x290 [ 47.872118] ? __ia32_sys_waitid+0x140/0x140 [ 47.876605] ? task_stopped_code+0x180/0x180 [ 47.881019] __do_sys_wait4+0x147/0x160 [ 47.884998] ? kernel_wait4+0x290/0x290 [ 47.888988] ? kasan_check_read+0x11/0x20 [ 47.893122] ? _copy_to_user+0xc9/0x120 [ 47.897098] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 47.902660] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 47.907678] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 47.912429] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 47.917179] ? do_syscall_64+0x26/0x620 [ 47.921142] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 47.926507] ? do_syscall_64+0x26/0x620 [ 47.930489] __x64_sys_wait4+0x97/0xf0 [ 47.934434] do_syscall_64+0xfd/0x620 [ 47.938251] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 47.943448] RIP: 0033:0x7f02cefdba3e [ 47.947949] 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 [ 47.966840] RSP: 002b:00007fff27a67e40 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 47.974535] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f02cefdba3e [ 47.981794] RDX: 0000000000000001 RSI: 00007fff27a67e7c RDI: ffffffffffffffff [ 47.989050] RBP: 000055aa32881c88 R08: 00007fff27a67f40 R09: 0101010101010101 [ 47.996317] R10: 0000000000000000 R11: 0000000000000246 R12: 000055aa3354caf0 [ 48.003587] R13: 000055aa3287ffb4 R14: 0000000000000028 R15: 000055aa32881ca0 [ 48.010863] [ 48.012476] Allocated by task 7573: [ 48.016098] save_stack+0x45/0xd0 [ 48.019538] kasan_kmalloc+0xce/0xf0 [ 48.023326] kasan_slab_alloc+0xf/0x20 [ 48.027197] kmem_cache_alloc_node+0x144/0x710 [ 48.031778] copy_process.part.0+0x1ce0/0x7a30 [ 48.036376] _do_fork+0x257/0xfd0 [ 48.039813] __x64_sys_clone+0xbf/0x150 [ 48.043777] do_syscall_64+0xfd/0x620 [ 48.047566] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.052732] [ 48.054343] Freed by task 0: [ 48.057362] save_stack+0x45/0xd0 [ 48.060798] __kasan_slab_free+0x102/0x150 [ 48.065116] kasan_slab_free+0xe/0x10 [ 48.068897] kmem_cache_free+0x86/0x260 [ 48.072857] free_task+0xdd/0x120 [ 48.076296] __put_task_struct+0x20f/0x4c0 [ 48.080514] finish_task_switch+0x52b/0x780 [ 48.084823] __schedule+0x86e/0x1dc0 [ 48.088526] schedule_idle+0x58/0x80 [ 48.092222] do_idle+0x192/0x560 [ 48.095571] cpu_startup_entry+0xc8/0xe0 [ 48.099615] rest_init+0x219/0x222 [ 48.103141] start_kernel+0x88c/0x8c5 [ 48.106938] x86_64_start_reservations+0x29/0x2b [ 48.111674] x86_64_start_kernel+0x77/0x7b [ 48.115908] secondary_startup_64+0xa4/0xb0 [ 48.120210] [ 48.121822] The buggy address belongs to the object at ffff8880858f4700 [ 48.121822] which belongs to the cache task_struct of size 6080 [ 48.134569] The buggy address is located 1132 bytes inside of [ 48.134569] 6080-byte region [ffff8880858f4700, ffff8880858f5ec0) [ 48.146603] The buggy address belongs to the page: [ 48.151524] page:ffffea0002163d00 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 [ 48.161482] flags: 0x1fffc0000008100(slab|head) [ 48.166151] raw: 01fffc0000008100 ffffea0002959808 ffffea00027ebb08 ffff88812c26d800 [ 48.174021] raw: 0000000000000000 ffff8880858f4700 0000000100000001 0000000000000000 [ 48.181901] page dumped because: kasan: bad access detected [ 48.187593] [ 48.189202] Memory state around the buggy address: [ 48.194201] ffff8880858f4a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.201544] ffff8880858f4a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.208886] >ffff8880858f4b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.216854] ^ [ 48.223592] ffff8880858f4b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.231036] ffff8880858f4c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.238374] ================================================================== [ 48.245738] Disabling lock debugging due to kernel taint [ 48.251283] Kernel panic - not syncing: panic_on_warn set ... [ 48.251283] [ 48.258648] CPU: 1 PID: 7573 Comm: sshd Tainted: G B 4.19.75 #0 [ 48.266005] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 48.275346] Call Trace: [ 48.277926] dump_stack+0x172/0x1f0 [ 48.281539] ? wait_consider_task+0x1b51/0x3910 [ 48.286196] panic+0x263/0x507 [ 48.289369] ? __warn_printk+0xf3/0xf3 [ 48.293390] ? retint_kernel+0x2d/0x2d [ 48.297356] ? trace_hardirqs_on+0x5e/0x220 [ 48.301697] ? wait_consider_task+0x1b51/0x3910 [ 48.306384] kasan_end_report+0x47/0x4f [ 48.310354] kasan_report.cold+0xa9/0x2ba [ 48.314494] __asan_report_load4_noabort+0x14/0x20 [ 48.319410] wait_consider_task+0x1b51/0x3910 [ 48.323895] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 48.329139] ? add_wait_queue+0x112/0x170 [ 48.333275] ? release_task+0x1630/0x1630 [ 48.337410] ? lock_acquire+0x16f/0x3f0 [ 48.341381] ? do_wait+0x3aa/0x9d0 [ 48.344909] ? kasan_check_write+0x14/0x20 [ 48.349129] do_wait+0x439/0x9d0 [ 48.352482] ? wait_consider_task+0x3910/0x3910 [ 48.357169] ? mark_held_locks+0x100/0x100 [ 48.361407] kernel_wait4+0x171/0x290 [ 48.365220] ? __ia32_sys_waitid+0x140/0x140 [ 48.369626] ? task_stopped_code+0x180/0x180 [ 48.374158] __do_sys_wait4+0x147/0x160 [ 48.378140] ? kernel_wait4+0x290/0x290 [ 48.382104] ? kasan_check_read+0x11/0x20 [ 48.386260] ? _copy_to_user+0xc9/0x120 [ 48.390226] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 48.395770] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 48.400780] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 48.405540] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 48.410283] ? do_syscall_64+0x26/0x620 [ 48.414273] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.419620] ? do_syscall_64+0x26/0x620 [ 48.423584] __x64_sys_wait4+0x97/0xf0 [ 48.427518] do_syscall_64+0xfd/0x620 [ 48.431305] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.436480] RIP: 0033:0x7f02cefdba3e [ 48.440178] 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 [ 48.459082] RSP: 002b:00007fff27a67e40 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 48.466779] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f02cefdba3e [ 48.474036] RDX: 0000000000000001 RSI: 00007fff27a67e7c RDI: ffffffffffffffff [ 48.481291] RBP: 000055aa32881c88 R08: 00007fff27a67f40 R09: 0101010101010101 [ 48.488544] R10: 0000000000000000 R11: 0000000000000246 R12: 000055aa3354caf0 [ 48.496926] R13: 000055aa3287ffb4 R14: 0000000000000028 R15: 000055aa32881ca0 [ 48.505921] Kernel Offset: disabled [ 48.509555] Rebooting in 86400 seconds..