======================================================== WARNING: possible irq lock inversion dependency detected 6.4.0-rc7-next-20230623 #1 Not tainted -------------------------------------------------------- syz-executor.5/5424 just changed the state of lock: ffffffff85815818 (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 *** 3 locks held by syz-executor.5/5424: #0: ffff88804326d470 (&fc->uapi_mutex){+.+.}-{3:3}, at: __do_sys_fsmount+0x2b6/0xa50 #1: ffffffff8560b5a0 (rcu_callback){....}-{0:0}, at: rcu_core+0x83e/0x28b0 #2: 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 _raw_spin_unlock_irqrestore+0x34/0x50 __wake_up_common_lock+0xe5/0x140 percpu_up_write+0x75/0x90 cgroup_procs_write_finish+0x136/0x170 __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 __cgroup_account_cputime+0x75/0xc0 update_curr+0x350/0x6d0 enqueue_task_fair+0x6a9/0x1ca0 activate_task+0xe7/0x250 ttwu_do_activate+0x10d/0x7a0 try_to_wake_up+0x627/0x1b30 __do_softirq+0x6de/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 do_set_pte+0x138/0x9d0 filemap_map_pages+0x520/0xdd0 __handle_mm_fault+0x1c9d/0x2d20 handle_mm_fault+0x1af/0xba0 do_user_addr_fault+0x58e/0x12f0 exc_page_fault+0x9c/0x1a0 asm_exc_page_fault+0x26/0x30 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 do_wp_page+0x3c8/0x3b00 __handle_mm_fault+0xcbc/0x2d20 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+0x8c8/0x28b0 __do_softirq+0x1b7/0x7d4 irq_exit_rcu+0x93/0xc0 sysvec_apic_timer_interrupt+0x6e/0x90 asm_sysvec_apic_timer_interrupt+0x1a/0x20 _raw_spin_unlock_irqrestore+0x34/0x50 ida_alloc_range+0x421/0x870 alloc_vfsmnt+0x4c/0x6c0 vfs_create_mount+0x8f/0x490 __do_sys_fsmount+0x421/0xa50 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+0x8c8/0x28b0 __do_softirq+0x1b7/0x7d4 irq_exit_rcu+0x93/0xc0 sysvec_apic_timer_interrupt+0x6e/0x90 asm_sysvec_apic_timer_interrupt+0x1a/0x20 _raw_spin_unlock_irqrestore+0x34/0x50 ida_alloc_range+0x421/0x870 alloc_vfsmnt+0x4c/0x6c0 vfs_create_mount+0x8f/0x490 __do_sys_fsmount+0x421/0xa50 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 do_wp_page+0x3c8/0x3b00 __handle_mm_fault+0xcbc/0x2d20 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+0x8c8/0x28b0 __do_softirq+0x1b7/0x7d4 irq_exit_rcu+0x93/0xc0 sysvec_apic_timer_interrupt+0x6e/0x90 asm_sysvec_apic_timer_interrupt+0x1a/0x20 _raw_spin_unlock_irqrestore+0x34/0x50 ida_alloc_range+0x421/0x870 alloc_vfsmnt+0x4c/0x6c0 vfs_create_mount+0x8f/0x490 __do_sys_fsmount+0x421/0xa50 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 stack backtrace: CPU: 0 PID: 5424 Comm: syz-executor.5 Not tainted 6.4.0-rc7-next-20230623 #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+0x8c8/0x28b0 __do_softirq+0x1b7/0x7d4 irq_exit_rcu+0x93/0xc0 sysvec_apic_timer_interrupt+0x6e/0x90 asm_sysvec_apic_timer_interrupt+0x1a/0x20 RIP: 0010:_raw_spin_unlock_irqrestore+0x34/0x50 Code: c7 18 53 48 89 f3 48 8b 74 24 10 e8 c6 db d8 fc 48 89 ef e8 8e 59 d9 fc 80 e7 02 74 06 e8 44 b5 fe fc fb 65 ff 0d 34 a4 ae 7b <74> 07 5b 5d e9 23 2a 00 00 0f 1f 44 00 00 5b 5d e9 17 2a 00 00 0f RSP: 0018:ffff888044527cc8 EFLAGS: 00000286 RAX: 0000000000000293 RBX: 0000000000000212 RCX: ffffffff812d1fbf RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8454e68c RBP: ffffffff856e3940 R08: 0000000000000001 R09: fffffbfff0ef9b78 R10: ffffffff877cdbc7 R11: 0000000000000001 R12: 00000000000001a5 R13: 000000007fffffff R14: ffff888044527d40 R15: 00000000000001a5 ida_alloc_range+0x421/0x870 alloc_vfsmnt+0x4c/0x6c0 vfs_create_mount+0x8f/0x490 __do_sys_fsmount+0x421/0xa50 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 RIP: 0033:0x7f7c5f9cbb19 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:00007f7c5cf41188 EFLAGS: 00000246 ORIG_RAX: 00000000000001b0 RAX: ffffffffffffffda RBX: 00007f7c5fadef60 RCX: 00007f7c5f9cbb19 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 00007f7c5fa25f6d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd2cf09caf R14: 00007f7c5cf41300 R15: 0000000000022000 audit: type=1326 audit(1687751826.383:16): auid=0 uid=0 gid=0 ses=4 subj=system_u:system_r:kernel_t:s0 pid=5440 comm="syz-executor.6" exe="/syz-executor.6" sig=31 arch=c000003e syscall=202 compat=0 ip=0x7f2e64136b19 code=0x0 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: 18 53 48 sbb %dl,0x48(%rbx) 3: 89 f3 mov %esi,%ebx 5: 48 8b 74 24 10 mov 0x10(%rsp),%rsi a: e8 c6 db d8 fc callq 0xfcd8dbd5 f: 48 89 ef mov %rbp,%rdi 12: e8 8e 59 d9 fc callq 0xfcd959a5 17: 80 e7 02 and $0x2,%bh 1a: 74 06 je 0x22 1c: e8 44 b5 fe fc callq 0xfcfeb565 21: fb sti 22: 65 ff 0d 34 a4 ae 7b decl %gs:0x7baea434(%rip) # 0x7baea45d * 29: 74 07 je 0x32 <-- trapping instruction 2b: 5b pop %rbx 2c: 5d pop %rbp 2d: e9 23 2a 00 00 jmpq 0x2a55 32: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 37: 5b pop %rbx 38: 5d pop %rbp 39: e9 17 2a 00 00 jmpq 0x2a55 3e: 0f .byte 0xf