====================================================== WARNING: possible circular locking dependency detected 4.15.0-rc9+ #9 Not tainted ------------------------------------------------------ syz-executor7/7500 is trying to acquire lock: (&event->child_mutex){+.+.}, at: [<0000000041df49fa>] perf_event_for_each_child+0x8a/0x150 kernel/events/core.c:4557 but task is already holding lock: (&cpuctx_mutex){+.+.}, at: [<000000009cf12ecd>] perf_event_ctx_lock_nested+0x21b/0x450 kernel/events/core.c:1249 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (&cpuctx_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 perf_event_init_cpu+0xb6/0x160 kernel/events/core.c:11076 perf_event_init+0x4e9/0x549 kernel/events/core.c:11123 start_kernel+0x4cc/0x819 init/main.c:627 x86_64_start_reservations+0x2a/0x2c arch/x86/kernel/head64.c:378 x86_64_start_kernel+0x77/0x7a arch/x86/kernel/head64.c:359 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:237 -> #4 (pmus_lock){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 perf_event_init_cpu+0x2f/0x160 kernel/events/core.c:11070 cpuhp_invoke_callback+0x2ea/0x1d20 kernel/cpu.c:182 cpuhp_up_callbacks kernel/cpu.c:477 [inline] _cpu_up+0x216/0x510 kernel/cpu.c:1036 do_cpu_up+0x73/0xa0 kernel/cpu.c:1066 cpu_up+0x18/0x20 kernel/cpu.c:1074 smp_init+0x13a/0x152 kernel/smp.c:578 kernel_init_freeable+0x2fe/0x521 init/main.c:1067 kernel_init+0x13/0x180 init/main.c:999 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:541 -> #3 (cpu_hotplug_lock.rw_sem){++++}: percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36 [inline] percpu_down_read include/linux/percpu-rwsem.h:59 [inline] cpus_read_lock+0x42/0x90 kernel/cpu.c:293 static_key_slow_inc+0x9d/0x3c0 kernel/jump_label.c:123 tracepoint_add_func kernel/tracepoint.c:223 [inline] tracepoint_probe_register_prio+0x80d/0x9a0 kernel/tracepoint.c:283 tracepoint_probe_register+0x2a/0x40 kernel/tracepoint.c:304 trace_event_reg+0x167/0x320 kernel/trace/trace_events.c:305 perf_trace_event_reg kernel/trace/trace_event_perf.c:122 [inline] perf_trace_event_init kernel/trace/trace_event_perf.c:197 [inline] perf_trace_init+0x4ef/0xab0 kernel/trace/trace_event_perf.c:221 perf_tp_event_init+0x7d/0xf0 kernel/events/core.c:7959 perf_try_init_event+0xc9/0x1f0 kernel/events/core.c:9192 perf_init_event kernel/events/core.c:9230 [inline] perf_event_alloc+0x1cc6/0x2b00 kernel/events/core.c:9494 SYSC_perf_event_open+0x84e/0x2e00 kernel/events/core.c:9949 SyS_perf_event_open+0x39/0x50 kernel/events/core.c:9835 entry_SYSCALL_64_fastpath+0x29/0xa0 -> #2 (tracepoints_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 tracepoint_probe_register_prio+0xa0/0x9a0 kernel/tracepoint.c:279 tracepoint_probe_register+0x2a/0x40 kernel/tracepoint.c:304 trace_event_reg+0x167/0x320 kernel/trace/trace_events.c:305 perf_trace_event_reg kernel/trace/trace_event_perf.c:122 [inline] perf_trace_event_init kernel/trace/trace_event_perf.c:197 [inline] perf_trace_init+0x4ef/0xab0 kernel/trace/trace_event_perf.c:221 perf_tp_event_init+0x7d/0xf0 kernel/events/core.c:7959 perf_try_init_event+0xc9/0x1f0 kernel/events/core.c:9192 perf_init_event kernel/events/core.c:9230 [inline] perf_event_alloc+0x1cc6/0x2b00 kernel/events/core.c:9494 SYSC_perf_event_open+0x84e/0x2e00 kernel/events/core.c:9949 SyS_perf_event_open+0x39/0x50 kernel/events/core.c:9835 entry_SYSCALL_64_fastpath+0x29/0xa0 -> #1 (event_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 perf_trace_destroy+0x28/0x100 kernel/trace/trace_event_perf.c:234 tp_perf_event_destroy+0x15/0x20 kernel/events/core.c:7943 _free_event+0x3bd/0x10f0 kernel/events/core.c:4104 free_event+0x84/0x150 kernel/events/core.c:4128 perf_event_release_kernel+0x54e/0xc10 kernel/events/core.c:4272 perf_release+0x37/0x50 kernel/events/core.c:4298 __fput+0x327/0x7e0 fs/file_table.c:210 ____fput+0x15/0x20 fs/file_table.c:244 task_work_run+0x199/0x270 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x9bb/0x1ad0 kernel/exit.c:865 do_group_exit+0x149/0x400 kernel/exit.c:968 get_signal+0x73f/0x16c0 kernel/signal.c:2335 do_signal+0x90/0x1eb0 arch/x86/kernel/signal.c:809 exit_to_usermode_loop+0x214/0x310 arch/x86/entry/common.c:158 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264 entry_SYSCALL_64_fastpath+0x9e/0xa0 -> #0 (&event->child_mutex){+.+.}: lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3914 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 perf_event_for_each_child+0x8a/0x150 kernel/events/core.c:4557 perf_event_for_each kernel/events/core.c:4574 [inline] _perf_ioctl kernel/events/core.c:4734 [inline] perf_ioctl+0x46b/0x1430 kernel/events/core.c:4748 vfs_ioctl fs/ioctl.c:46 [inline] do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 entry_SYSCALL_64_fastpath+0x29/0xa0 other info that might help us debug this: Chain exists of: &event->child_mutex --> pmus_lock --> &cpuctx_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&cpuctx_mutex); lock(pmus_lock); lock(&cpuctx_mutex); lock(&event->child_mutex); *** DEADLOCK *** 1 lock held by syz-executor7/7500: #0: (&cpuctx_mutex){+.+.}, at: [<000000009cf12ecd>] perf_event_ctx_lock_nested+0x21b/0x450 kernel/events/core.c:1249 stack backtrace: CPU: 0 PID: 7500 Comm: syz-executor7 Not tainted 4.15.0-rc9+ #9 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 print_circular_bug.isra.37+0x2cd/0x2dc kernel/locking/lockdep.c:1218 check_prev_add kernel/locking/lockdep.c:1858 [inline] check_prevs_add kernel/locking/lockdep.c:1971 [inline] validate_chain kernel/locking/lockdep.c:2412 [inline] __lock_acquire+0x30a8/0x3e00 kernel/locking/lockdep.c:3426 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3914 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 perf_event_for_each_child+0x8a/0x150 kernel/events/core.c:4557 perf_event_for_each kernel/events/core.c:4574 [inline] _perf_ioctl kernel/events/core.c:4734 [inline] perf_ioctl+0x46b/0x1430 kernel/events/core.c:4748 vfs_ioctl fs/ioctl.c:46 [inline] do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 entry_SYSCALL_64_fastpath+0x29/0xa0 RIP: 0033:0x453299 RSP: 002b:00007fd5dca84c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fd5dca85700 RCX: 0000000000453299 RDX: ffffffffffffffff RSI: 0000000000002403 RDI: 0000000000000012 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000 R13: 00007ffd6a182c3f R14: 00007fd5dca859c0 R15: 0000000000000000 IPVS: ftp: loaded support on port[0] = 21 overlayfs: missing 'lowerdir' 9pnet_virtio: no channels available for device ./file1 hrtimer: interrupt took 25880 ns 9pnet_virtio: no channels available for device ./file1 9pnet_virtio: no channels available for device ./file0 tmpfs: No value for mount option '}G$9YױKtt'_0'U§' IPVS: ftp: loaded support on port[0] = 21 tmpfs: No value for mount option 'D' tmpfs: No value for mount option 'D' tmpfs: No value for mount option 'oRm1r&!ꨉ/I1`! o' tmpfs: No value for mount option 'oRm1r&!ꨉ/I1`! o' FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 1 CPU: 1 PID: 8506 Comm: syz-executor5 Not tainted 4.15.0-rc9+ #9 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 fail_dump lib/fault-inject.c:51 [inline] should_fail+0x8c0/0xa40 lib/fault-inject.c:149 should_failslab+0xec/0x120 mm/failslab.c:32 slab_pre_alloc_hook mm/slab.h:421 [inline] slab_alloc_node mm/slab.c:3289 [inline] kmem_cache_alloc_node+0x56/0x760 mm/slab.c:3632 __alloc_skb+0xf1/0x780 net/core/skbuff.c:193 alloc_skb include/linux/skbuff.h:983 [inline] alloc_skb_with_frags+0x10d/0x750 net/core/skbuff.c:5151 sock_alloc_send_pskb+0x787/0x9b0 net/core/sock.c:2088 unix_dgram_sendmsg+0x52d/0x1610 net/unix/af_unix.c:1682 sock_sendmsg_nosec net/socket.c:630 [inline] sock_sendmsg+0xca/0x110 net/socket.c:640 ___sys_sendmsg+0x767/0x8b0 net/socket.c:2046 __sys_sendmsg+0xe5/0x210 net/socket.c:2080 SYSC_sendmsg net/socket.c:2091 [inline] SyS_sendmsg+0x2d/0x50 net/socket.c:2087 entry_SYSCALL_64_fastpath+0x29/0xa0 RIP: 0033:0x453299 RSP: 002b:00007f191d568c58 EFLAGS: 00000212 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f191d568aa0 RCX: 0000000000453299 RDX: 0000000000000000 RSI: 000000002023b000 RDI: 0000000000000013 RBP: 00007f191d568a90 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 00000000004b8096 R13: 00007f191d568bc8 R14: 00000000004b8096 R15: 0000000000000000 FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 CPU: 1 PID: 8532 Comm: syz-executor5 Not tainted 4.15.0-rc9+ #9 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 fail_dump lib/fault-inject.c:51 [inline] should_fail+0x8c0/0xa40 lib/fault-inject.c:149 should_failslab+0xec/0x120 mm/failslab.c:32 slab_pre_alloc_hook mm/slab.h:421 [inline] slab_alloc_node mm/slab.c:3289 [inline] kmem_cache_alloc_node_trace+0x5a/0x750 mm/slab.c:3651 __do_kmalloc_node mm/slab.c:3671 [inline] __kmalloc_node_track_caller+0x33/0x70 mm/slab.c:3686 __kmalloc_reserve.isra.39+0x41/0xd0 net/core/skbuff.c:137 __alloc_skb+0x13b/0x780 net/core/skbuff.c:205 alloc_skb include/linux/skbuff.h:983 [inline] alloc_skb_with_frags+0x10d/0x750 net/core/skbuff.c:5151 sock_alloc_send_pskb+0x787/0x9b0 net/core/sock.c:2088 unix_dgram_sendmsg+0x52d/0x1610 net/unix/af_unix.c:1682 sock_sendmsg_nosec net/socket.c:630 [inline] sock_sendmsg+0xca/0x110 net/socket.c:640 ___sys_sendmsg+0x767/0x8b0 net/socket.c:2046 __sys_sendmsg+0xe5/0x210 net/socket.c:2080 SYSC_sendmsg net/socket.c:2091 [inline] SyS_sendmsg+0x2d/0x50 net/socket.c:2087 entry_SYSCALL_64_fastpath+0x29/0xa0 RIP: 0033:0x453299 RSP: 002b:00007f191d568c58 EFLAGS: 00000212 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f191d568aa0 RCX: 0000000000453299 RDX: 0000000000000000 RSI: 000000002023b000 RDI: 0000000000000013 RBP: 00007f191d568a90 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 00000000004b8096 R13: 00007f191d568bc8 R14: 00000000004b8096 R15: 0000000000000000 autofs4:pid:8543:autofs4_fill_super: called with bogus options autofs4:pid:8556:autofs4_fill_super: called with bogus options autofs4:pid:8578:autofs4_fill_super: called with bogus options IPVS: ftp: loaded support on port[0] = 21 can: request_module (can-proto-0) failed. can: request_module (can-proto-0) failed. audit: type=1400 audit(1517356049.363:19): avc: denied { setopt } for pid=8691 comm="syz-executor4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:unlabeled_t:s0 tclass=socket permissive=1 audit: type=1400 audit(1517356049.386:20): avc: denied { write } for pid=8691 comm="syz-executor4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:unlabeled_t:s0 tclass=socket permissive=1 rpcbind: RPC call returned error 22 rpcbind: RPC call returned error 22 autofs4:pid:8790:autofs4_fill_super: called with bogus options autofs4:pid:8790:autofs4_fill_super: called with bogus options FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 CPU: 1 PID: 8817 Comm: syz-executor2 Not tainted 4.15.0-rc9+ #9 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 fail_dump lib/fault-inject.c:51 [inline] should_fail+0x8c0/0xa40 lib/fault-inject.c:149 should_failslab+0xec/0x120 mm/failslab.c:32 slab_pre_alloc_hook mm/slab.h:421 [inline] slab_alloc mm/slab.c:3368 [inline] kmem_cache_alloc+0x47/0x760 mm/slab.c:3542 kmem_cache_zalloc include/linux/slab.h:678 [inline] mmap_region+0x7ee/0x15a0 mm/mmap.c:1673 do_mmap+0x6c0/0xe00 mm/mmap.c:1483 do_mmap_pgoff include/linux/mm.h:2217 [inline] vm_mmap_pgoff+0x1de/0x280 mm/util.c:333 SYSC_mmap_pgoff mm/mmap.c:1533 [inline] SyS_mmap_pgoff+0x23b/0x5f0 mm/mmap.c:1491 SYSC_mmap arch/x86/kernel/sys_x86_64.c:100 [inline] SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:91 entry_SYSCALL_64_fastpath+0x29/0xa0 RIP: 0033:0x453299 RSP: 002b:00007f649dfaec58 EFLAGS: 00000212 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f649dfaeaa0 RCX: 0000000000453299 RDX: 0000000000000003 RSI: 000000000037c000 RDI: 0000000020000000 RBP: 00007f649dfaea90 R08: ffffffffffffffff R09: 0000000000000000 R10: 4a8db012d8386cb2 R11: 0000000000000212 R12: 00000000004b8096 R13: 00007f649dfaebc8 R14: 00000000004b8096 R15: 0000000000000000 FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 CPU: 0 PID: 8827 Comm: syz-executor2 Not tainted 4.15.0-rc9+ #9 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 fail_dump lib/fault-inject.c:51 [inline] should_fail+0x8c0/0xa40 lib/fault-inject.c:149 should_failslab+0xec/0x120 mm/failslab.c:32 slab_pre_alloc_hook mm/slab.h:421 [inline] slab_alloc mm/slab.c:3368 [inline] kmem_cache_alloc+0x47/0x760 mm/slab.c:3542 anon_vma_chain_alloc mm/rmap.c:128 [inline] __anon_vma_prepare+0xbc/0x6b0 mm/rmap.c:182 anon_vma_prepare include/linux/rmap.h:153 [inline] do_huge_pmd_anonymous_page+0x1127/0x1b00 mm/huge_memory.c:678 create_huge_pmd mm/memory.c:3834 [inline] __handle_mm_fault+0x1a0c/0x3ce0 mm/memory.c:4038 handle_mm_fault+0x334/0x8d0 mm/memory.c:4104 faultin_page mm/gup.c:502 [inline] __get_user_pages+0x50c/0x15f0 mm/gup.c:699 populate_vma_page_range+0x20e/0x2f0 mm/gup.c:1216 __mm_populate+0x23a/0x450 mm/gup.c:1266 mm_populate include/linux/mm.h:2226 [inline] vm_mmap_pgoff+0x241/0x280 mm/util.c:338 SYSC_mmap_pgoff mm/mmap.c:1533 [inline] SyS_mmap_pgoff+0x23b/0x5f0 mm/mmap.c:1491 SYSC_mmap arch/x86/kernel/sys_x86_64.c:100 [inline] SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:91 entry_SYSCALL_64_fastpath+0x29/0xa0 RIP: 0033:0x453299 RSP: 002b:00007f649dfaec58 EFLAGS: 00000212 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f649dfaeaa0 RCX: 0000000000453299 RDX: 0000000000000003 RSI: 000000000037c000 RDI: 0000000020000000 RBP: 00007f649dfaea90 R08: ffffffffffffffff R09: 0000000000000000 R10: 4a8db012d8386cb2 R11: 0000000000000212 R12: 00000000004b8096 R13: 00007f649dfaebc8 R14: 00000000004b8096 R15: 0000000000000000 FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 CPU: 0 PID: 8836 Comm: syz-executor2 Not tainted 4.15.0-rc9+ #9 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 fail_dump lib/fault-inject.c:51 [inline] should_fail+0x8c0/0xa40 lib/fault-inject.c:149 should_failslab+0xec/0x120 mm/failslab.c:32 slab_pre_alloc_hook mm/slab.h:421 [inline] slab_alloc mm/slab.c:3368 [inline] kmem_cache_alloc+0x47/0x760 mm/slab.c:3542 anon_vma_alloc mm/rmap.c:81 [inline] __anon_vma_prepare+0x39d/0x6b0 mm/rmap.c:189 anon_vma_prepare include/linux/rmap.h:153 [inline] do_huge_pmd_anonymous_page+0x1127/0x1b00 mm/huge_memory.c:678 create_huge_pmd mm/memory.c:3834 [inline] __handle_mm_fault+0x1a0c/0x3ce0 mm/memory.c:4038 handle_mm_fault+0x334/0x8d0 mm/memory.c:4104 faultin_page mm/gup.c:502 [inline] __get_user_pages+0x50c/0x15f0 mm/gup.c:699 populate_vma_page_range+0x20e/0x2f0 mm/gup.c:1216 __mm_populate+0x23a/0x450 mm/gup.c:1266 mm_populate include/linux/mm.h:2226 [inline] vm_mmap_pgoff+0x241/0x280 mm/util.c:338 SYSC_mmap_pgoff mm/mmap.c:1533 [inline] SyS_mmap_pgoff+0x23b/0x5f0 mm/mmap.c:1491 SYSC_mmap arch/x86/kernel/sys_x86_64.c:100 [inline] SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:91 entry_SYSCALL_64_fastpath+0x29/0xa0 RIP: 0033:0x453299 RSP: 002b:00007f649dfaec58 EFLAGS: 00000212 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f649dfaeaa0 RCX: 0000000000453299 RDX: 0000000000000003 RSI: 000000000037c000 RDI: 0000000020000000 RBP: 00007f649dfaea90 R08: ffffffffffffffff R09: 0000000000000000 R10: 4a8db012d8386cb2 R11: 0000000000000212 R12: 00000000004b8096 R13: 00007f649dfaebc8 R14: 00000000004b8096 R15: 0000000000000000 autofs4:pid:8850:autofs4_fill_super: called with bogus options FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 CPU: 0 PID: 8872 Comm: syz-executor2 Not tainted 4.15.0-rc9+ #9 proc: unrecognized mount option "" or missing value Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 fail_dump lib/fault-inject.c:51 [inline] should_fail+0x8c0/0xa40 lib/fault-inject.c:149 should_failslab+0xec/0x120 mm/failslab.c:32