EXT4-fs error (device loop4): __ext4_fill_super:5467: inode #2: comm syz-executor.4: iget: special inode unallocated EXT4-fs (loop4): get root inode failed EXT4-fs (loop4): mount failed ======================================================== WARNING: possible irq lock inversion dependency detected 6.4.0-rc7-next-20230622 #1 Not tainted -------------------------------------------------------- syz-executor.6/4292 just changed the state of lock: ffffffff85814c18 (blkg_stat_lock){+.-.}-{2:2}, at: __blkcg_rstat_flush.isra.0+0x11f/0x4e0 but this lock was taken by another, HARDIRQ-safe lock in the past: (per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu)){-.-.}-{2:2} and interrupts could create inverse lock ordering between them. other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(blkg_stat_lock); local_irq_disable(); lock(per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu)); lock(blkg_stat_lock); lock(per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu)); *** DEADLOCK *** 6 locks held by syz-executor.6/4292: #0: ffffffff85b6bed0 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x2fe/0x770 #1: ffffffff85b775a8 (rtnl_mutex){+.+.}-{3:3}, at: register_netdev+0x15/0x60 #2: ffff88806cf38980 (lock){+.+.}-{2:2}, at: __radix_tree_preload+0x0/0x6b0 #3: ffffffff85715878 (kernfs_idr_lock){+.+.}-{2:2}, at: __kernfs_new_node+0xff/0x890 #4: ffffffff8560b5a0 (rcu_callback){....}-{0:0}, at: rcu_core+0x83e/0x2860 #5: ffffffff8560b6c0 (rcu_read_lock){....}-{1:2}, at: __blkcg_rstat_flush.isra.0+0x93/0x4e0 the shortest dependencies between 2nd lock and 1st lock: -> (per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu)){-.-.}-{2:2} { IN-HARDIRQ-W at: lock_acquire+0x19a/0x4c0 _raw_spin_lock_irqsave+0x3a/0x60 cgroup_rstat_updated+0xcb/0x2e0 __cgroup_account_cputime_field+0xa0/0x120 account_system_index_time+0x199/0x2c0 update_process_times+0x26/0x150 tick_sched_handle+0x8e/0x170 tick_sched_timer+0xe6/0x110 __hrtimer_run_queues+0x17f/0xb60 hrtimer_interrupt+0x2ef/0x750 __sysvec_apic_timer_interrupt+0xff/0x380 sysvec_apic_timer_interrupt+0x69/0x90 asm_sysvec_apic_timer_interrupt+0x1a/0x20 get_page_from_freelist+0x18f1/0x3020 __alloc_pages+0x1cb/0x480 alloc_pages+0x1a0/0x260 allocate_slab+0x26c/0x320 ___slab_alloc+0x973/0x1190 kmem_cache_alloc+0x34e/0x370 __create_object+0x3c/0xc90 kmem_cache_alloc+0x20b/0x370 getname_flags.part.0+0x50/0x4f0 getname+0x92/0xe0 do_sys_openat2+0xec/0x1d0 __x64_sys_openat+0x143/0x200 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 IN-SOFTIRQ-W at: lock_acquire+0x19a/0x4c0 _raw_spin_lock_irqsave+0x3a/0x60 cgroup_rstat_updated+0xcb/0x2e0 __cgroup_account_cputime+0x75/0xc0 update_curr+0x350/0x6d0 dequeue_task_fair+0x20e/0x14a0 load_balance+0xcb4/0x2790 rebalance_domains+0x66c/0xc00 __do_softirq+0x1b7/0x7d4 irq_exit_rcu+0x93/0xc0 sysvec_apic_timer_interrupt+0x38/0x90 asm_sysvec_apic_timer_interrupt+0x1a/0x20 INITIAL USE at: lock_acquire+0x19a/0x4c0 _raw_spin_lock_irqsave+0x3a/0x60 cgroup_rstat_flush_locked+0x131/0xd80 cgroup_rstat_flush+0x37/0x50 do_flush_stats+0x97/0xf0 flush_memcg_stats_dwork+0x9/0x50 process_one_work+0xabf/0x1770 worker_thread+0x64f/0x12a0 kthread+0x33f/0x440 ret_from_fork+0x2c/0x50 } ... key at: [] __key.0+0x0/0x40 ... acquired at: _raw_spin_lock+0x2b/0x40 __blkcg_rstat_flush.isra.0+0x11f/0x4e0 blkcg_rstat_flush+0x87/0xb0 cgroup_rstat_flush_locked+0x706/0xd80 cgroup_rstat_flush+0x37/0x50 do_flush_stats+0x97/0xf0 mem_cgroup_wb_stats+0x3d8/0x4b0 balance_dirty_pages+0x339/0x2640 balance_dirty_pages_ratelimited_flags+0xbce/0x1130 fault_dirty_shared_page+0x2b3/0x500 __handle_mm_fault+0xfb7/0x2bf0 handle_mm_fault+0x1af/0xba0 do_user_addr_fault+0x58e/0x12f0 exc_page_fault+0x9c/0x1a0 asm_exc_page_fault+0x26/0x30 -> (blkg_stat_lock){+.-.}-{2:2} { HARDIRQ-ON-W at: lock_acquire+0x19a/0x4c0 _raw_spin_lock+0x2b/0x40 __blkcg_rstat_flush.isra.0+0x11f/0x4e0 __blkg_release+0xfa/0x3b0 rcu_core+0x8c8/0x2860 __do_softirq+0x1b7/0x7d4 irq_exit_rcu+0x93/0xc0 sysvec_apic_timer_interrupt+0x6e/0x90 asm_sysvec_apic_timer_interrupt+0x1a/0x20 __sanitizer_cov_trace_pc+0x0/0x70 __radix_tree_replace+0x19a/0x2f0 idr_alloc_u32+0x1e0/0x2d0 idr_alloc_cyclic+0x106/0x230 __kernfs_new_node+0x117/0x890 kernfs_new_node+0x97/0x120 __kernfs_create_file+0x55/0x350 sysfs_add_file_mode_ns+0x21c/0x440 internal_create_group+0x322/0xb00 internal_create_groups.part.0+0x90/0x140 sysfs_create_groups+0x29/0x50 device_add+0x5bc/0x18a0 netdev_register_kobject+0x17e/0x3b0 register_netdevice+0xd60/0x1530 register_netdev+0x31/0x60 loopback_net_init+0x7a/0x180 ops_init+0xbb/0x6b0 setup_net+0x3d9/0x990 copy_net_ns+0x321/0x770 create_new_namespaces+0x3f6/0xb30 copy_namespaces+0x414/0x500 copy_process+0x2b78/0x7320 kernel_clone+0xeb/0x7d0 __do_sys_clone3+0x1d5/0x250 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 IN-SOFTIRQ-W at: lock_acquire+0x19a/0x4c0 _raw_spin_lock+0x2b/0x40 __blkcg_rstat_flush.isra.0+0x11f/0x4e0 __blkg_release+0xfa/0x3b0 rcu_core+0x8c8/0x2860 __do_softirq+0x1b7/0x7d4 irq_exit_rcu+0x93/0xc0 sysvec_apic_timer_interrupt+0x6e/0x90 asm_sysvec_apic_timer_interrupt+0x1a/0x20 __sanitizer_cov_trace_pc+0x0/0x70 __radix_tree_replace+0x19a/0x2f0 idr_alloc_u32+0x1e0/0x2d0 idr_alloc_cyclic+0x106/0x230 __kernfs_new_node+0x117/0x890 kernfs_new_node+0x97/0x120 __kernfs_create_file+0x55/0x350 sysfs_add_file_mode_ns+0x21c/0x440 internal_create_group+0x322/0xb00 internal_create_groups.part.0+0x90/0x140 sysfs_create_groups+0x29/0x50 device_add+0x5bc/0x18a0 netdev_register_kobject+0x17e/0x3b0 register_netdevice+0xd60/0x1530 register_netdev+0x31/0x60 loopback_net_init+0x7a/0x180 ops_init+0xbb/0x6b0 setup_net+0x3d9/0x990 copy_net_ns+0x321/0x770 create_new_namespaces+0x3f6/0xb30 copy_namespaces+0x414/0x500 copy_process+0x2b78/0x7320 kernel_clone+0xeb/0x7d0 __do_sys_clone3+0x1d5/0x250 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 INITIAL USE at: lock_acquire+0x19a/0x4c0 _raw_spin_lock+0x2b/0x40 __blkcg_rstat_flush.isra.0+0x11f/0x4e0 blkcg_rstat_flush+0x87/0xb0 cgroup_rstat_flush_locked+0x706/0xd80 cgroup_rstat_flush+0x37/0x50 do_flush_stats+0x97/0xf0 mem_cgroup_wb_stats+0x3d8/0x4b0 balance_dirty_pages+0x339/0x2640 balance_dirty_pages_ratelimited_flags+0xbce/0x1130 fault_dirty_shared_page+0x2b3/0x500 __handle_mm_fault+0xfb7/0x2bf0 handle_mm_fault+0x1af/0xba0 do_user_addr_fault+0x58e/0x12f0 exc_page_fault+0x9c/0x1a0 asm_exc_page_fault+0x26/0x30 } ... key at: [] blkg_stat_lock+0x18/0x60 ... acquired at: __lock_acquire+0x8b8/0x6340 lock_acquire+0x19a/0x4c0 _raw_spin_lock+0x2b/0x40 __blkcg_rstat_flush.isra.0+0x11f/0x4e0 __blkg_release+0xfa/0x3b0 rcu_core+0x8c8/0x2860 __do_softirq+0x1b7/0x7d4 irq_exit_rcu+0x93/0xc0 sysvec_apic_timer_interrupt+0x6e/0x90 asm_sysvec_apic_timer_interrupt+0x1a/0x20 __sanitizer_cov_trace_pc+0x0/0x70 __radix_tree_replace+0x19a/0x2f0 idr_alloc_u32+0x1e0/0x2d0 idr_alloc_cyclic+0x106/0x230 __kernfs_new_node+0x117/0x890 kernfs_new_node+0x97/0x120 __kernfs_create_file+0x55/0x350 sysfs_add_file_mode_ns+0x21c/0x440 internal_create_group+0x322/0xb00 internal_create_groups.part.0+0x90/0x140 sysfs_create_groups+0x29/0x50 device_add+0x5bc/0x18a0 netdev_register_kobject+0x17e/0x3b0 register_netdevice+0xd60/0x1530 register_netdev+0x31/0x60 loopback_net_init+0x7a/0x180 ops_init+0xbb/0x6b0 setup_net+0x3d9/0x990 copy_net_ns+0x321/0x770 create_new_namespaces+0x3f6/0xb30 copy_namespaces+0x414/0x500 copy_process+0x2b78/0x7320 kernel_clone+0xeb/0x7d0 __do_sys_clone3+0x1d5/0x250 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 stack backtrace: CPU: 1 PID: 4292 Comm: syz-executor.6 Not tainted 6.4.0-rc7-next-20230622 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 Call Trace: dump_stack_lvl+0x91/0xf0 print_irq_inversion_bug.part.0+0x3d5/0x570 mark_lock.part.0+0x900/0x2f50 __lock_acquire+0x8b8/0x6340 lock_acquire+0x19a/0x4c0 _raw_spin_lock+0x2b/0x40 __blkcg_rstat_flush.isra.0+0x11f/0x4e0 __blkg_release+0xfa/0x3b0 rcu_core+0x8c8/0x2860 __do_softirq+0x1b7/0x7d4 irq_exit_rcu+0x93/0xc0 sysvec_apic_timer_interrupt+0x6e/0x90 asm_sysvec_apic_timer_interrupt+0x1a/0x20 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x70 Code: be b0 01 00 00 e8 a0 ff ff ff 31 c0 e9 a9 7b 07 03 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 65 8b 05 8d 54 b7 7e 89 c1 48 8b 34 24 81 e1 00 01 00 RSP: 0018:ffff888042097150 EFLAGS: 00000202 RAX: 0000000000000004 RBX: ffff88801be541c0 RCX: ffffffff844d29ae RDX: ffff8880425251c0 RSI: 0000000000000000 RDI: 0000000000000005 RBP: ffff88801be54000 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000004 R11: 0000000000000001 R12: 0000000008000004 R13: ffff888008784810 R14: ffff88803f254570 R15: 0000000000000000 __radix_tree_replace+0x19a/0x2f0 idr_alloc_u32+0x1e0/0x2d0 idr_alloc_cyclic+0x106/0x230 __kernfs_new_node+0x117/0x890 kernfs_new_node+0x97/0x120 __kernfs_create_file+0x55/0x350 sysfs_add_file_mode_ns+0x21c/0x440 internal_create_group+0x322/0xb00 internal_create_groups.part.0+0x90/0x140 sysfs_create_groups+0x29/0x50 device_add+0x5bc/0x18a0 netdev_register_kobject+0x17e/0x3b0 register_netdevice+0xd60/0x1530 register_netdev+0x31/0x60 loopback_net_init+0x7a/0x180 ops_init+0xbb/0x6b0 setup_net+0x3d9/0x990 copy_net_ns+0x321/0x770 create_new_namespaces+0x3f6/0xb30 copy_namespaces+0x414/0x500 copy_process+0x2b78/0x7320 kernel_clone+0xeb/0x7d0 __do_sys_clone3+0x1d5/0x250 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 RIP: 0033:0x7fa20b0beb19 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fa208634188 EFLAGS: 00000246 ORIG_RAX: 00000000000001b3 RAX: ffffffffffffffda RBX: 00007fa20b1d1f60 RCX: 00007fa20b0beb19 RDX: 0000000000000000 RSI: 0000000000000058 RDI: 0000000020004c00 RBP: 00007fa20b118f6d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc8e16531f R14: 00007fa208634300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: be b0 01 00 00 mov $0x1b0,%esi 5: e8 a0 ff ff ff callq 0xffffffaa a: 31 c0 xor %eax,%eax c: e9 a9 7b 07 03 jmpq 0x3077bba 11: 66 0f 1f 84 00 00 00 nopw 0x0(%rax,%rax,1) 18: 00 00 1a: 90 nop 1b: 90 nop 1c: 90 nop 1d: 90 nop 1e: 90 nop 1f: 90 nop 20: 90 nop 21: 90 nop 22: 90 nop 23: 90 nop 24: 90 nop 25: 90 nop 26: 90 nop 27: 90 nop 28: 90 nop 29: 90 nop * 2a: f3 0f 1e fa endbr64 <-- trapping instruction 2e: 65 8b 05 8d 54 b7 7e mov %gs:0x7eb7548d(%rip),%eax # 0x7eb754c2 35: 89 c1 mov %eax,%ecx 37: 48 8b 34 24 mov (%rsp),%rsi 3b: 81 .byte 0x81 3c: e1 00 loope 0x3e 3e: 01 00 add %eax,(%rax)