EXT4-fs (loop2): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none. EXT4-fs (loop2): unmounting filesystem 00000000-0000-0000-0000-000000000000. ======================================================== WARNING: possible irq lock inversion dependency detected 6.4.0-rc7-next-20230621 #1 Not tainted -------------------------------------------------------- syz-fuzzer/248 just changed the state of lock: ffffffff85814e18 (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 *** 2 locks held by syz-fuzzer/248: #0: ffffffff8560b520 (rcu_callback){....}-{0:0}, at: rcu_core+0x83e/0x2860 #1: ffffffff8560b640 (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 lock_acquire+0x1c7/0x4c0 __flush_workqueue+0x10d/0x1110 cgroup_procs_write_finish+0xeb/0x170 __cgroup_procs_write+0x371/0x6b0 cgroup_procs_write+0x26/0x60 cgroup_file_write+0x1e5/0x7c0 kernfs_fop_write_iter+0x3f7/0x610 vfs_write+0x97d/0xda0 ksys_write+0x122/0x250 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 __mod_memcg_state+0x86/0x160 memcg_account_kmem+0x38/0x70 refill_obj_stock+0x35f/0x5c0 kmem_cache_free+0x444/0x4d0 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 unwind_next_frame+0xc66/0x2490 arch_stack_walk+0x87/0xf0 stack_trace_save+0x90/0xd0 kasan_save_stack+0x22/0x50 __kasan_record_aux_stack+0x8e/0xa0 __call_rcu_common.constprop.0+0x6a/0xb90 __kmem_cache_free+0x95/0x330 security_context_to_sid_core+0x3c4/0x870 selinux_kernfs_init_security+0x19c/0x4c0 security_kernfs_init_security+0x52/0xb0 __kernfs_new_node+0x54d/0x890 kernfs_new_node+0x97/0x120 __kernfs_create_file+0x55/0x350 cgroup_addrm_files+0x3c8/0x9f0 css_populate_dir+0x19a/0x4e0 cgroup_apply_control_enable+0x3ae/0xa40 cgroup_mkdir+0x78e/0x10b0 kernfs_iop_mkdir+0x151/0x1e0 vfs_mkdir+0x24b/0x470 do_mkdirat+0x163/0x2d0 __x64_sys_mkdir+0xf6/0x150 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 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 generic_perform_write+0x390/0x5e0 ext4_buffered_write_iter+0x123/0x3d0 ext4_file_write_iter+0x36d/0x19b0 vfs_write+0x97d/0xda0 ksys_write+0x122/0x250 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 -> (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+0x38/0x90 asm_sysvec_apic_timer_interrupt+0x1a/0x20 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+0x38/0x90 asm_sysvec_apic_timer_interrupt+0x1a/0x20 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 generic_perform_write+0x390/0x5e0 ext4_buffered_write_iter+0x123/0x3d0 ext4_file_write_iter+0x36d/0x19b0 vfs_write+0x97d/0xda0 ksys_write+0x122/0x250 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 } ... 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+0x38/0x90 asm_sysvec_apic_timer_interrupt+0x1a/0x20 stack backtrace: CPU: 0 PID: 248 Comm: syz-fuzzer Not tainted 6.4.0-rc7-next-20230621 #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+0x38/0x90 asm_sysvec_apic_timer_interrupt+0x1a/0x20 RIP: 0033:0x4666e0 Code: 0f 05 89 44 24 20 c3 cc cc cc 8b 7c 24 08 48 8b 74 24 10 8b 54 24 18 44 8b 54 24 1c 49 c7 c0 00 00 00 00 b8 19 01 00 00 0f 05 <89> 44 24 20 c3 cc cc cc cc cc cc cc cc cc cc cc 8b 7c 24 08 48 c7 RSP: 002b:000000c0000bb7f0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00000000004666e0 RDX: 0000000000000080 RSI: 000000c0000bb840 RDI: 0000000000000003 RBP: 000000c0000bbe40 R08: 0000000000000000 R09: 00007ffc12df1080 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 000000c000082c00 R14: 0000005c00dee47f R15: 0000000000000039 program syz-executor.7 is using a deprecated SCSI ioctl, please convert it to SG_IO loop5: detected capacity change from 0 to 264192 syz-executor.2: attempt to access beyond end of device loop2: rw=0, sector=0, nr_sectors = 1 limit=0 FAT-fs (loop2): unable to read boot sector tmpfs: Unknown parameter 'È“‰Ë¡*wQ\Wö$' loop5: detected capacity change from 0 to 264192 syz-executor.2: attempt to access beyond end of device loop2: rw=0, sector=0, nr_sectors = 1 limit=0 FAT-fs (loop2): unable to read boot sector tmpfs: Unknown parameter 'È“‰Ë¡*wQ\Wö$' loop5: detected capacity change from 0 to 264192 tmpfs: Unknown parameter 'È“‰Ë¡*wQ\Wö$' tmpfs: Unknown parameter 'È“‰Ë¡*wQ\Wö$' syz-executor.5: attempt to access beyond end of device loop5: rw=0, sector=0, nr_sectors = 1 limit=0 FAT-fs (loop5): unable to read boot sector