overlayfs: filesystem on './bus' not supported as upperdir INFO: task syz-executor.1:640 blocked for more than 140 seconds. Not tainted 4.19.172-syzkaller #0 overlayfs: fs on './file0' does not support file handles, falling back to index=off,nfs_export=off. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D29016 640 8107 0x00000000 overlayfs: filesystem on './bus' not supported as upperdir overlayfs: unrecognized mount option "lo"§’werdr=.A&" or missing value Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x887/0x2040 kernel/sched/core.c:3517 schedule+0x8d/0x1b0 kernel/sched/core.c:3561 d_wait_lookup fs/dcache.c:2430 [inline] d_alloc_parallel+0x1292/0x19e0 fs/dcache.c:2512 lookup_open+0x4ea/0x1a20 fs/namei.c:3148 do_last fs/namei.c:3327 [inline] path_openat+0x1804/0x2df0 fs/namei.c:3537 overlayfs: lowerdir is in-use as upperdir/workdir of another mount, mount with '-o index=off' to override exclusive upperdir protection. do_filp_open+0x18c/0x3f0 fs/namei.c:3567 overlayfs: filesystem on './bus' not supported as upperdir do_sys_open+0x3b3/0x520 fs/open.c:1085 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465b09 Code: Bad RIP value. RSP: 002b:00007fa996bac188 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 000000000056c008 RCX: 0000000000465b09 RDX: 0000000000000000 RSI: 00000000200020c0 RDI: ffffffffffffff9c RBP: 00000000004b069f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c008 R13: 00007ffeb255fc0f R14: 00007fa996bac300 R15: 0000000000022000 Showing all locks held in the system: 1 lock held by khungtaskd/1566: #0: 00000000bb69dcf7 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4440 1 lock held by in:imklog/7873: 2 locks held by agetty/8034: #0: 000000007bd41a6c (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272 #1: 0000000012d60507 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x217/0x1950 drivers/tty/n_tty.c:2154 1 lock held by syz-executor.0/8105: #0: 000000005038be5b (&xt[i].mutex){+.+.}, at: xt_find_table_lock+0x3d/0x430 net/netfilter/x_tables.c:1211 1 lock held by syz-executor.1/8107: #0: 000000005038be5b (&xt[i].mutex){+.+.}, at: xt_find_table_lock+0x3d/0x430 net/netfilter/x_tables.c:1211 1 lock held by syz-executor.2/8109: #0: 000000005038be5b (&xt[i].mutex){+.+.}, at: xt_find_table_lock+0x3d/0x430 net/netfilter/x_tables.c:1211 1 lock held by syz-executor.3/8111: #0: 0000000081607fab (rcu_preempt_state.exp_mutex){+.+.}, at: exp_funnel_lock kernel/rcu/tree_exp.h:329 [inline] #0: 0000000081607fab (rcu_preempt_state.exp_mutex){+.+.}, at: _synchronize_rcu_expedited+0x256/0x6f0 kernel/rcu/tree_exp.h:667 1 lock held by syz-executor.4/8114: #0: 000000005038be5b (&xt[i].mutex){+.+.}, at: xt_find_table_lock+0x3d/0x430 net/netfilter/x_tables.c:1211 2 locks held by syz-executor.5/8118: #0: 000000005038be5b (&xt[i].mutex){+.+.}, at: xt_find_table_lock+0x3d/0x430 net/netfilter/x_tables.c:1211 #1: 0000000081607fab (rcu_preempt_state.exp_mutex){+.+.}, at: exp_funnel_lock kernel/rcu/tree_exp.h:297 [inline] #1: 0000000081607fab (rcu_preempt_state.exp_mutex){+.+.}, at: _synchronize_rcu_expedited+0x4dc/0x6f0 kernel/rcu/tree_exp.h:667 2 locks held by syz-executor.1/602: #0: 00000000d80b0edd (&type->i_mutex_dir_key#8){++++}, at: inode_lock_shared include/linux/fs.h:758 [inline] #0: 00000000d80b0edd (&type->i_mutex_dir_key#8){++++}, at: do_last fs/namei.c:3326 [inline] #0: 00000000d80b0edd (&type->i_mutex_dir_key#8){++++}, at: path_openat+0x17ec/0x2df0 fs/namei.c:3537 #1: 0000000057c5bfe1 (&fi->mutex){+.+.}, at: fuse_lock_inode+0xaf/0xe0 fs/fuse/inode.c:365 1 lock held by syz-executor.1/640: #0: 00000000d80b0edd (&type->i_mutex_dir_key#8){++++}, at: inode_lock_shared include/linux/fs.h:758 [inline] #0: 00000000d80b0edd (&type->i_mutex_dir_key#8){++++}, at: do_last fs/namei.c:3326 [inline] #0: 00000000d80b0edd (&type->i_mutex_dir_key#8){++++}, at: path_openat+0x17ec/0x2df0 fs/namei.c:3537 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1566 Comm: khungtaskd Not tainted 4.19.172-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1a6/0x1f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x991/0xe60 kernel/hung_task.c:287 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4683 Comm: systemd-journal Not tainted 4.19.172-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:end_of_stack include/linux/sched/task_stack.h:28 [inline] RIP: 0010:schedule_debug kernel/sched/core.c:3329 [inline] RIP: 0010:__schedule+0xd6/0x2040 kernel/sched/core.c:3439 Code: ff 48 89 c2 48 89 85 58 ff ff ff 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 23 1a 00 00 4d 8b a7 20 0a 00 00 <48> b8 00 00 00 00 00 fc ff df 49 8d 7c 24 18 48 89 fa 48 c1 ea 03 RSP: 0018:ffff8880a122fb08 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff83758bc3 RDX: 1ffff1101740574c RSI: ffffffff83758bd1 RDI: ffffffff89cf0f00 RBP: ffff8880a122fbd0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000005 R11: 0000000000000000 R12: ffff8880a1220380 R13: 000000000002b040 R14: dffffc0000000000 R15: ffff8880ba02b040 FS: 00007f11f3b918c0(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f11f1261000 CR3: 00000000a145e000 CR4: 00000000001426f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: schedule+0x8d/0x1b0 kernel/sched/core.c:3561 schedule_hrtimeout_range_clock+0x33e/0x390 kernel/time/hrtimer.c:1938 ep_poll+0xabb/0xcb0 fs/eventpoll.c:1817 do_epoll_wait+0x1aa/0x200 fs/eventpoll.c:2190 __do_sys_epoll_wait fs/eventpoll.c:2200 [inline] __se_sys_epoll_wait fs/eventpoll.c:2197 [inline] __x64_sys_epoll_wait+0x93/0xf0 fs/eventpoll.c:2197 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f11f2e5b2e3 Code: 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 83 3d 29 54 2b 00 00 75 13 49 89 ca b8 e8 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 34 c3 48 83 ec 08 e8 0b c2 00 00 48 89 04 24 RSP: 002b:00007ffcdfa05408 EFLAGS: 00000246 ORIG_RAX: 00000000000000e8 RAX: ffffffffffffffda RBX: 000056316b1f01e0 RCX: 00007f11f2e5b2e3 RDX: 0000000000000013 RSI: 00007ffcdfa05410 RDI: 0000000000000008 RBP: 00007ffcdfa05600 R08: 00007ffcdfa49000 R09: 000000b5145cfa81 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffcdfa05410 R13: 0000000000000001 R14: ffffffffffffffff R15: 0005ba6625707c23