[ OK ] Started Getty on tty2. [ OK ] Started Getty on tty1. [ OK ] Started Serial Getty on ttyS0. [ OK ] Reached target Login Prompts. [ OK ] Started OpenBSD Secure Shell server. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.10.50' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 70.959590][ T8493] ================================================================== [ 70.968116][ T8493] BUG: KASAN: null-ptr-deref in bdi_put+0x22/0xa0 [ 70.974833][ T8493] Write of size 4 at addr 0000000000000040 by task syz-executor656/8493 [ 70.983363][ T8493] [ 70.985686][ T8493] CPU: 0 PID: 8493 Comm: syz-executor656 Not tainted 5.10.0-next-20201223-syzkaller #0 [ 70.995425][ T8493] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 71.005603][ T8493] Call Trace: [ 71.008883][ T8493] dump_stack+0x107/0x163 [ 71.013217][ T8493] ? bdi_put+0x22/0xa0 [ 71.017279][ T8493] ? bdi_put+0x22/0xa0 [ 71.021342][ T8493] kasan_report.cold+0x5f/0xd5 [ 71.026107][ T8493] ? bdi_put+0x22/0xa0 [ 71.030240][ T8493] check_memory_region+0x13d/0x180 [ 71.035393][ T8493] bdi_put+0x22/0xa0 [ 71.039282][ T8493] bdev_evict_inode+0x262/0x460 [ 71.044174][ T8493] ? __blkdev_direct_IO_simple+0x930/0x930 [ 71.050086][ T8493] evict+0x2ed/0x6b0 [ 71.055164][ T8493] iput.part.0+0x57e/0x810 [ 71.059857][ T8493] ? find_inode_nowait+0x190/0x190 [ 71.065088][ T8493] iput+0x58/0x70 [ 71.068899][ T8493] dentry_unlink_inode+0x2b1/0x3d0 [ 71.074101][ T8493] __dentry_kill+0x3c0/0x640 [ 71.078843][ T8493] ? dput+0x35/0xbc0 [ 71.083127][ T8493] ? dput+0x35/0xbc0 [ 71.087110][ T8493] dput+0x725/0xbc0 [ 71.090960][ T8493] shrink_dcache_for_umount+0x11f/0x330 [ 71.096633][ T8493] generic_shutdown_super+0x68/0x370 [ 71.101937][ T8493] kill_anon_super+0x36/0x60 [ 71.106667][ T8493] deactivate_locked_super+0x94/0x160 [ 71.112036][ T8493] deactivate_super+0xad/0xd0 [ 71.116708][ T8493] put_fs_context+0xaa/0x650 [ 71.121294][ T8493] ? __sanitizer_cov_trace_const_cmp2+0x22/0x80 [ 71.127576][ T8493] fscontext_release+0x4c/0x60 [ 71.132565][ T8493] __fput+0x283/0x920 [ 71.136568][ T8493] ? fs_validate_description+0x1d0/0x1d0 [ 71.142207][ T8493] task_work_run+0xdd/0x190 [ 71.146717][ T8493] do_exit+0xb89/0x29e0 [ 71.150882][ T8493] ? mm_update_next_owner+0x7a0/0x7a0 [ 71.156252][ T8493] ? __do_sys_fsconfig+0x1c2/0xbd0 [ 71.161365][ T8493] ? fscontext_read+0x310/0x310 [ 71.166220][ T8493] do_group_exit+0x125/0x310 [ 71.170863][ T8493] __x64_sys_exit_group+0x3a/0x50 [ 71.175885][ T8493] do_syscall_64+0x2d/0x70 [ 71.180313][ T8493] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 71.186207][ T8493] RIP: 0033:0x43ee78 [ 71.190101][ T8493] Code: Unable to access opcode bytes at RIP 0x43ee4e. [ 71.196968][ T8493] RSP: 002b:00007ffca755ebd8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 71.205375][ T8493] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ee78 [ 71.213342][ T8493] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 71.221308][ T8493] RBP: 00000000004be688 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 71.229309][ T8493] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 71.237274][ T8493] R13: 00000000006d0180 R14: 0000000000000000 R15: 0000000000000000 [ 71.245395][ T8493] ================================================================== [ 71.253451][ T8493] Disabling lock debugging due to kernel taint [ 71.262457][ T8493] Kernel panic - not syncing: panic_on_warn set ... [ 71.269055][ T8493] CPU: 0 PID: 8493 Comm: syz-executor656 Tainted: G B 5.10.0-next-20201223-syzkaller #0 [ 71.280082][ T8493] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 71.290377][ T8493] Call Trace: [ 71.293651][ T8493] dump_stack+0x107/0x163 [ 71.298019][ T8493] ? bdi_alloc+0xc0/0x140 [ 71.302342][ T8493] panic+0x306/0x73d [ 71.306235][ T8493] ? __warn_printk+0xf3/0xf3 [ 71.310861][ T8493] ? preempt_schedule_common+0x59/0xc0 [ 71.316313][ T8493] ? bdi_put+0x22/0xa0 [ 71.321795][ T8493] ? preempt_schedule_thunk+0x16/0x18 [ 71.327162][ T8493] ? trace_hardirqs_on+0x38/0x1c0 [ 71.332181][ T8493] ? trace_hardirqs_on+0x51/0x1c0 [ 71.337205][ T8493] ? bdi_put+0x22/0xa0 [ 71.341310][ T8493] ? bdi_put+0x22/0xa0 [ 71.345369][ T8493] end_report+0x58/0x5e [ 71.349520][ T8493] kasan_report.cold+0x67/0xd5 [ 71.354320][ T8493] ? bdi_put+0x22/0xa0 [ 71.358380][ T8493] check_memory_region+0x13d/0x180 [ 71.363607][ T8493] bdi_put+0x22/0xa0 [ 71.367492][ T8493] bdev_evict_inode+0x262/0x460 [ 71.372336][ T8493] ? __blkdev_direct_IO_simple+0x930/0x930 [ 71.378134][ T8493] evict+0x2ed/0x6b0 [ 71.382108][ T8493] iput.part.0+0x57e/0x810 [ 71.386602][ T8493] ? find_inode_nowait+0x190/0x190 [ 71.391794][ T8493] iput+0x58/0x70 [ 71.395418][ T8493] dentry_unlink_inode+0x2b1/0x3d0 [ 71.400528][ T8493] __dentry_kill+0x3c0/0x640 [ 71.405115][ T8493] ? dput+0x35/0xbc0 [ 71.409003][ T8493] ? dput+0x35/0xbc0 [ 71.412934][ T8493] dput+0x725/0xbc0 [ 71.416754][ T8493] shrink_dcache_for_umount+0x11f/0x330 [ 71.422331][ T8493] generic_shutdown_super+0x68/0x370 [ 71.427620][ T8493] kill_anon_super+0x36/0x60 [ 71.432207][ T8493] deactivate_locked_super+0x94/0x160 [ 71.437571][ T8493] deactivate_super+0xad/0xd0 [ 71.442238][ T8493] put_fs_context+0xaa/0x650 [ 71.446820][ T8493] ? __sanitizer_cov_trace_const_cmp2+0x22/0x80 [ 71.453057][ T8493] fscontext_release+0x4c/0x60 [ 71.457814][ T8493] __fput+0x283/0x920 [ 71.461825][ T8493] ? fs_validate_description+0x1d0/0x1d0 [ 71.467486][ T8493] task_work_run+0xdd/0x190 [ 71.472027][ T8493] do_exit+0xb89/0x29e0 [ 71.476239][ T8493] ? mm_update_next_owner+0x7a0/0x7a0 [ 71.481634][ T8493] ? __do_sys_fsconfig+0x1c2/0xbd0 [ 71.486737][ T8493] ? fscontext_read+0x310/0x310 [ 71.491578][ T8493] do_group_exit+0x125/0x310 [ 71.496158][ T8493] __x64_sys_exit_group+0x3a/0x50 [ 71.501173][ T8493] do_syscall_64+0x2d/0x70 [ 71.505616][ T8493] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 71.511503][ T8493] RIP: 0033:0x43ee78 [ 71.515382][ T8493] Code: Unable to access opcode bytes at RIP 0x43ee4e. [ 71.522208][ T8493] RSP: 002b:00007ffca755ebd8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 71.530611][ T8493] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ee78 [ 71.538577][ T8493] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 71.546542][ T8493] RBP: 00000000004be688 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 71.554501][ T8493] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 71.562465][ T8493] R13: 00000000006d0180 R14: 0000000000000000 R15: 0000000000000000 [ 71.571413][ T8493] Kernel Offset: disabled [ 71.575797][ T8493] Rebooting in 86400 seconds..