======================================================== WARNING: possible irq lock inversion dependency detected 6.7.0-rc1-next-20231116-syzkaller #0 Not tainted -------------------------------------------------------- syz-executor394/5112 just changed the state of lock: ffffffff8cff86b8 (css_set_lock){..-.}-{2:2}, at: put_css_set kernel/cgroup/cgroup-internal.h:208 [inline] ffffffff8cff86b8 (css_set_lock){..-.}-{2:2}, at: put_css_set kernel/cgroup/cgroup-internal.h:196 [inline] ffffffff8cff86b8 (css_set_lock){..-.}-{2:2}, at: cgroup_free+0x7c/0x1d0 kernel/cgroup/cgroup.c:6748 but this lock took another, SOFTIRQ-unsafe lock in the past: (&sighand->siglock){+.+.}-{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(&sighand->siglock); local_irq_disable(); lock(css_set_lock); lock(&sighand->siglock); lock(css_set_lock); *** DEADLOCK *** 3 locks held by syz-executor394/5112: #0: ffffffff8cc0a098 (tasklist_lock){++++}-{2:2}, at: ptrace_stop.part.0+0x2af/0x780 kernel/signal.c:2304 #1: ffffffff8cfacf40 (rcu_callback){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:301 [inline] #1: ffffffff8cfacf40 (rcu_callback){....}-{0:0}, at: rcu_do_batch kernel/rcu/tree.c:2152 [inline] #1: ffffffff8cfacf40 (rcu_callback){....}-{0:0}, at: rcu_core+0x7cc/0x16b0 kernel/rcu/tree.c:2431 #2: ffffffff8ce58800 (put_task_map-wait-type-override){+...}-{3:3}, at: put_task_struct include/linux/sched/task.h:135 [inline] #2: ffffffff8ce58800 (put_task_map-wait-type-override){+...}-{3:3}, at: put_task_struct include/linux/sched/task.h:123 [inline] #2: ffffffff8ce58800 (put_task_map-wait-type-override){+...}-{3:3}, at: delayed_put_task_struct+0x21e/0x2d0 kernel/exit.c:227 the shortest dependencies between 2nd lock and 1st lock: -> (&sighand->siglock){+.+.}-{2:2} { HARDIRQ-ON-W at: lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1b1/0x530 kernel/locking/lockdep.c:5718 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] class_spinlock_constructor include/linux/spinlock.h:530 [inline] ptrace_set_stopped kernel/ptrace.c:391 [inline] ptrace_attach+0x401/0x650 kernel/ptrace.c:478 __do_sys_ptrace+0x204/0x230 kernel/ptrace.c:1290 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x62/0x6a SOFTIRQ-ON-W at: lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1b1/0x530 kernel/locking/lockdep.c:5718 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] class_spinlock_constructor include/linux/spinlock.h:530 [inline] ptrace_set_stopped kernel/ptrace.c:391 [inline] ptrace_attach+0x401/0x650 kernel/ptrace.c:478 __do_sys_ptrace+0x204/0x230 kernel/ptrace.c:1290 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x62/0x6a INITIAL USE at: lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1b1/0x530 kernel/locking/lockdep.c:5718 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline] _raw_spin_lock_irq+0x36/0x50 kernel/locking/spinlock.c:170 spin_lock_irq include/linux/spinlock.h:376 [inline] calculate_sigpending+0x44/0xa0 kernel/signal.c:197 ret_from_fork+0x23/0x80 arch/x86/kernel/process.c:143 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 } ... key at: [] __key.341+0x0/0x40 ... acquired at: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162 __lock_task_sighand+0xc2/0x340 kernel/signal.c:1422 lock_task_sighand include/linux/sched/signal.h:748 [inline] cgroup_freeze_task+0x80/0x190 kernel/cgroup/freezer.c:160 cgroup_freezer_migrate_task+0x1b7/0x3a0 kernel/cgroup/freezer.c:257 cgroup_migrate_execute+0x2d3/0x1230 kernel/cgroup/cgroup.c:2580 cgroup_attach_task+0x5a8/0x8e0 kernel/cgroup/cgroup.c:2888 __cgroup_procs_write+0x311/0x540 kernel/cgroup/cgroup.c:5196 cgroup_procs_write+0x26/0x50 kernel/cgroup/cgroup.c:5209 cgroup_file_write+0x209/0x7c0 kernel/cgroup/cgroup.c:4092 kernfs_fop_write_iter+0x33f/0x500 fs/kernfs/file.c:334 call_write_iter include/linux/fs.h:2021 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x64d/0xdf0 fs/read_write.c:584 ksys_write+0x12f/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x62/0x6a -> (css_set_lock){..-.}-{2:2} { IN-SOFTIRQ-W at: lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1b1/0x530 kernel/locking/lockdep.c:5718 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162 put_css_set kernel/cgroup/cgroup-internal.h:208 [inline] put_css_set kernel/cgroup/cgroup-internal.h:196 [inline] cgroup_free+0x7c/0x1d0 kernel/cgroup/cgroup.c:6748 __put_task_struct+0x10b/0x3d0 kernel/fork.c:992 put_task_struct include/linux/sched/task.h:136 [inline] put_task_struct include/linux/sched/task.h:123 [inline] delayed_put_task_struct+0x22c/0x2d0 kernel/exit.c:227 rcu_do_batch kernel/rcu/tree.c:2158 [inline] rcu_core+0x828/0x16b0 kernel/rcu/tree.c:2431 __do_softirq+0x216/0x8d5 kernel/softirq.c:553 invoke_softirq kernel/softirq.c:427 [inline] __irq_exit_rcu kernel/softirq.c:632 [inline] irq_exit_rcu+0xb5/0x120 kernel/softirq.c:644 sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1076 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] _raw_spin_unlock_irqrestore+0x31/0x70 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] do_notify_parent_cldstop+0x557/0xb60 kernel/signal.c:2213 ptrace_stop.part.0+0x644/0x780 kernel/signal.c:2316 ptrace_stop kernel/signal.c:2255 [inline] ptrace_do_notify+0x22b/0x2e0 kernel/signal.c:2390 ptrace_notify+0xc5/0x130 kernel/signal.c:2402 ptrace_report_syscall include/linux/ptrace.h:411 [inline] ptrace_report_syscall_entry include/linux/ptrace.h:448 [inline] syscall_trace_enter.constprop.0+0xad/0x1f0 kernel/entry/common.c:65 __syscall_enter_from_user_work kernel/entry/common.c:94 [inline] syscall_enter_from_user_mode+0xf5/0x110 kernel/entry/common.c:112 do_syscall_64+0x1c/0x110 arch/x86/entry/common.c:78 entry_SYSCALL_64_after_hwframe+0x62/0x6a INITIAL USE at: lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1b1/0x530 kernel/locking/lockdep.c:5718 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline] _raw_spin_lock_irq+0x36/0x50 kernel/locking/spinlock.c:170 spin_lock_irq include/linux/spinlock.h:376 [inline] cgroup_setup_root+0x62c/0xa00 kernel/cgroup/cgroup.c:2138 cgroup_init+0x23f/0x1100 kernel/cgroup/cgroup.c:6120 start_kernel+0x385/0x480 init/main.c:1063 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:555 x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:536 secondary_startup_64_no_verify+0x166/0x16b } ... key at: [] css_set_lock+0x18/0x60 ... acquired at: mark_usage kernel/locking/lockdep.c:4566 [inline] __lock_acquire+0x13c2/0x3b10 kernel/locking/lockdep.c:5090 lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1b1/0x530 kernel/locking/lockdep.c:5718 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162 put_css_set kernel/cgroup/cgroup-internal.h:208 [inline] put_css_set kernel/cgroup/cgroup-internal.h:196 [inline] cgroup_free+0x7c/0x1d0 kernel/cgroup/cgroup.c:6748 __put_task_struct+0x10b/0x3d0 kernel/fork.c:992 put_task_struct include/linux/sched/task.h:136 [inline] put_task_struct include/linux/sched/task.h:123 [inline] delayed_put_task_struct+0x22c/0x2d0 kernel/exit.c:227 rcu_do_batch kernel/rcu/tree.c:2158 [inline] rcu_core+0x828/0x16b0 kernel/rcu/tree.c:2431 __do_softirq+0x216/0x8d5 kernel/softirq.c:553 invoke_softirq kernel/softirq.c:427 [inline] __irq_exit_rcu kernel/softirq.c:632 [inline] irq_exit_rcu+0xb5/0x120 kernel/softirq.c:644 sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1076 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] _raw_spin_unlock_irqrestore+0x31/0x70 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] do_notify_parent_cldstop+0x557/0xb60 kernel/signal.c:2213 ptrace_stop.part.0+0x644/0x780 kernel/signal.c:2316 ptrace_stop kernel/signal.c:2255 [inline] ptrace_do_notify+0x22b/0x2e0 kernel/signal.c:2390 ptrace_notify+0xc5/0x130 kernel/signal.c:2402 ptrace_report_syscall include/linux/ptrace.h:411 [inline] ptrace_report_syscall_entry include/linux/ptrace.h:448 [inline] syscall_trace_enter.constprop.0+0xad/0x1f0 kernel/entry/common.c:65 __syscall_enter_from_user_work kernel/entry/common.c:94 [inline] syscall_enter_from_user_mode+0xf5/0x110 kernel/entry/common.c:112 do_syscall_64+0x1c/0x110 arch/x86/entry/common.c:78 entry_SYSCALL_64_after_hwframe+0x62/0x6a stack backtrace: CPU: 1 PID: 5112 Comm: syz-executor394 Not tainted 6.7.0-rc1-next-20231116-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 print_irq_inversion_bug.part.0+0x3e1/0x590 kernel/locking/lockdep.c:4079 print_irq_inversion_bug kernel/locking/lockdep.c:4032 [inline] check_usage_forwards kernel/locking/lockdep.c:4110 [inline] mark_lock_irq kernel/locking/lockdep.c:4242 [inline] mark_lock+0x570/0xc50 kernel/locking/lockdep.c:4677 mark_usage kernel/locking/lockdep.c:4566 [inline] __lock_acquire+0x13c2/0x3b10 kernel/locking/lockdep.c:5090 lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1b1/0x530 kernel/locking/lockdep.c:5718 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162 put_css_set kernel/cgroup/cgroup-internal.h:208 [inline] put_css_set kernel/cgroup/cgroup-internal.h:196 [inline] cgroup_free+0x7c/0x1d0 kernel/cgroup/cgroup.c:6748 __put_task_struct+0x10b/0x3d0 kernel/fork.c:992 put_task_struct include/linux/sched/task.h:136 [inline] put_task_struct include/linux/sched/task.h:123 [inline] delayed_put_task_struct+0x22c/0x2d0 kernel/exit.c:227 rcu_do_batch kernel/rcu/tree.c:2158 [inline] rcu_core+0x828/0x16b0 kernel/rcu/tree.c:2431 __do_softirq+0x216/0x8d5 kernel/softirq.c:553 invoke_softirq kernel/softirq.c:427 [inline] __irq_exit_rcu kernel/softirq.c:632 [inline] irq_exit_rcu+0xb5/0x120 kernel/softirq.c:644 sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1076 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x70 kernel/locking/spinlock.c:194 Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 f6 c8 e3 f6 48 89 df e8 ae 40 e4 f6 f7 c5 00 02 00 00 75 1f 9c 58 f6 c4 02 75 2f 01 00 00 00 e8 65 ee d5 f6 65 8b 05 86 19 7f 75 85 c0 74 12 5b RSP: 0018:ffffc90003d47c68 EFLAGS: 00000246 RAX: 0000000000000002 RBX: ffff8880287d9bc0 RCX: 1ffffffff23e4388 RDX: 0000000000000000 RSI: ffffffff8accbfe0 RDI: ffffffff8b2f13e0 RBP: 0000000000000246 R08: 0000000000000001 R09: fffffbfff23e31ea R10: ffffffff91f18f57 R11: 0000000000000003 R12: ffff8880287d9bc0 R13: ffff88801a799dc0 R14: ffffc90003d47d00 R15: 0000000000000246 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] do_notify_parent_cldstop+0x557/0xb60 kernel/signal.c:2213 ptrace_stop.part.0+0x644/0x780 kernel/signal.c:2316 ptrace_stop kernel/signal.c:2255 [inline] ptrace_do_notify+0x22b/0x2e0 kernel/signal.c:2390 ptrace_notify+0xc5/0x130 kernel/signal.c:2402 ptrace_report_syscall include/linux/ptrace.h:411 [inline] ptrace_report_syscall_entry include/linux/ptrace.h:448 [inline] syscall_trace_enter.constprop.0+0xad/0x1f0 kernel/entry/common.c:65 __syscall_enter_from_user_work kernel/entry/common.c:94 [inline] syscall_enter_from_user_mode+0xf5/0x110 kernel/entry/common.c:112 do_syscall_64+0x1c/0x110 arch/x86/entry/common.c:78 entry_SYSCALL_64_after_hwframe+0x62/0x6a RIP: 0033:0x7fd945b5b8e7 Code: 44 00 00 48 c7 c0 b0 ff ff ff 64 c7 00 16 00 00 00 31 c0 eb b4 e8 39 46 fd ff 66 0f 1f 84 00 00 00 00 00 b8 6d 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffffab4d8d8 EFLAGS: 00000246 ORIG_RAX: 000000000000006d RAX: ffffffffffffffda RBX: 0000555555a92700 RCX: 00007fd945b5b8e7 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 00007fd945bbefc0 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffffab4d8f4 R13: 00007ffffab4d950 R14: 00007ffffab4d990 R15: 00007fd945af9200 ---------------- Code disassembly (best guess): 0: f5 cmc 1: 53 push %rbx 2: 48 8b 74 24 10 mov 0x10(%rsp),%rsi 7: 48 89 fb mov %rdi,%rbx a: 48 83 c7 18 add $0x18,%rdi e: e8 f6 c8 e3 f6 call 0xf6e3c909 13: 48 89 df mov %rbx,%rdi 16: e8 ae 40 e4 f6 call 0xf6e440c9 1b: f7 c5 00 02 00 00 test $0x200,%ebp 21: 75 1f jne 0x42 23: 9c pushf 24: 58 pop %rax 25: f6 c4 02 test $0x2,%ah 28: 75 2f jne 0x59 * 2a: bf 01 00 00 00 mov $0x1,%edi <-- trapping instruction 2f: e8 65 ee d5 f6 call 0xf6d5ee99 34: 65 8b 05 86 19 7f 75 mov %gs:0x757f1986(%rip),%eax # 0x757f19c1 3b: 85 c0 test %eax,%eax 3d: 74 12 je 0x51 3f: 5b pop %rbx