======================================================== WARNING: possible irq lock inversion dependency detected 6.4.0-rc7-next-20230623 #1 Not tainted -------------------------------------------------------- syz-executor.4/5948 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 *** 6 locks held by syz-executor.4/5948: #0: ffff888017ec01a0 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x4b8/0x12f0 #1: ffff88800ffc44e0 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x1a6/0x500 #2: ffff8880197785a0 (mapping.invalidate_lock){++++}-{3:3}, at: ext4_page_mkwrite+0x355/0x15f0 #3: ffffffff8560b6c0 (rcu_read_lock){....}-{1:2}, at: folio_memcg_lock+0x4/0x4b0 #4: ffffffff8560b5a0 (rcu_callback){....}-{0:0}, at: rcu_core+0x83e/0x28b0 #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 unwind_next_frame+0x584/0x2490 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/0xbd0 kmem_cache_free+0xc1/0x4d0 seq_release+0x62/0x80 kernfs_fop_release+0xf6/0x1e0 __fput+0x406/0xad0 task_work_run+0x174/0x280 exit_to_user_mode_prepare+0x17d/0x180 syscall_exit_to_user_mode+0x1d/0x50 do_syscall_64+0x4c/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+0x6e/0x90 asm_sysvec_apic_timer_interrupt+0x1a/0x20 _raw_spin_unlock_irqrestore+0x34/0x50 __wake_up_common_lock+0xe5/0x140 d_add+0x3cc/0x780 simple_lookup+0xd1/0x110 __lookup_slow+0x252/0x470 walk_component+0x345/0x5b0 path_lookupat+0x1ba/0x850 filename_lookup+0x1d2/0x590 user_path_at_empty+0x46/0x70 do_faccessat+0x127/0xae0 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 wb_over_bg_thresh+0x30e/0x6a0 wb_workfn+0x486/0xed0 process_one_work+0xabf/0x1770 worker_thread+0x64f/0x12a0 kthread+0x33f/0x440 ret_from_fork+0x2c/0x50 -> (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 mark_buffer_dirty+0x2e0/0x390 __block_commit_write.constprop.0+0x108/0x260 block_page_mkwrite+0x404/0x4b0 ext4_page_mkwrite+0x1045/0x15f0 do_page_mkwrite+0x1a6/0x500 __handle_mm_fault+0xf49/0x2d20 handle_mm_fault+0x1af/0xba0 do_user_addr_fault+0x58e/0x12f0 exc_page_fault+0x9c/0x1a0 asm_exc_page_fault+0x26/0x30 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 mark_buffer_dirty+0x2e0/0x390 __block_commit_write.constprop.0+0x108/0x260 block_page_mkwrite+0x404/0x4b0 ext4_page_mkwrite+0x1045/0x15f0 do_page_mkwrite+0x1a6/0x500 __handle_mm_fault+0xf49/0x2d20 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+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 wb_over_bg_thresh+0x30e/0x6a0 wb_workfn+0x486/0xed0 process_one_work+0xabf/0x1770 worker_thread+0x64f/0x12a0 kthread+0x33f/0x440 ret_from_fork+0x2c/0x50 } ... 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 mark_buffer_dirty+0x2e0/0x390 __block_commit_write.constprop.0+0x108/0x260 block_page_mkwrite+0x404/0x4b0 ext4_page_mkwrite+0x1045/0x15f0 do_page_mkwrite+0x1a6/0x500 __handle_mm_fault+0xf49/0x2d20 handle_mm_fault+0x1af/0xba0 do_user_addr_fault+0x58e/0x12f0 exc_page_fault+0x9c/0x1a0 asm_exc_page_fault+0x26/0x30 stack backtrace: CPU: 1 PID: 5948 Comm: syz-executor.4 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: 0000:ffff888016e3fb50 EFLAGS: 00000286 RAX: 000000000000146f RBX: 0000000000000293 RCX: ffffffff812d1fbf RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8454e68c RBP: ffff8880197784e0 R08: 0000000000000001 R09: fffffbfff0ef9b6c R10: ffffffff877cdb67 R11: 0000000000000001 R12: 0000000000000000 R13: dffffc0000000000 R14: 0000000000000001 R15: 0000000000000000 mark_buffer_dirty+0x2e0/0x390 __block_commit_write.constprop.0+0x108/0x260 block_page_mkwrite+0x404/0x4b0 ext4_page_mkwrite+0x1045/0x15f0 do_page_mkwrite+0x1a6/0x500 __handle_mm_fault+0xf49/0x2d20 handle_mm_fault+0x1af/0xba0 do_user_addr_fault+0x58e/0x12f0 exc_page_fault+0x9c/0x1a0 asm_exc_page_fault+0x26/0x30 RIP: 0033:0x7f32a2b9a673 Code: 5d c3 0f 1f 44 00 00 48 8b 0d 59 ed 0a 01 48 8b 05 4a ed 0a 01 4c 8d 81 00 00 00 01 48 39 c8 72 13 4c 39 c0 73 0e 48 8d 50 04 <89> 38 48 89 15 2c ed 0a 01 c3 52 48 8d 35 77 b7 0b 00 48 89 c2 48 RSP: 002b:00007ffd5ebe3078 EFLAGS: 00010287 RAX: 0000001b2c835000 RBX: 00007f32a2774008 RCX: 0000001b2c820000 RDX: 0000001b2c835004 RSI: ffffffff816287a0 RDI: 000000005345a631 RBP: 0000000000000001 R08: 0000001b2d820000 R09: 0000001b2c82e9e8 R10: 0000000000000634 R11: 000000005345a635 R12: 000000000000dab2 R13: 00007f32a2d04000 R14: ffffffff816287a0 R15: 00007f32a2d100b0 loop2: detected capacity change from 0 to 40 ---------------- 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