===================================================== WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected 6.7.0-rc1-syzkaller #0 Not tainted ----------------------------------------------------- syz-executor.0/1866 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: ffff888105662bd8 (&sighand->siglock){+.+.}-{2:2}, at: __lock_task_sighand+0x67/0x1a0 kernel/signal.c:1422 and this task is already holding: ffffffff825830b8 (css_set_lock){..-.}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:376 [inline] ffffffff825830b8 (css_set_lock){..-.}-{2:2}, at: cgroup_migrate_execute+0xb2/0x500 kernel/cgroup/cgroup.c:2553 which would create a new lock dependency: (css_set_lock){..-.}-{2:2} -> (&sighand->siglock){+.+.}-{2:2} but this new dependency connects a SOFTIRQ-irq-safe lock: (css_set_lock){..-.}-{2:2} ... which became SOFTIRQ-irq-safe at: lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0xcd/0x2d0 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+0x35/0xc0 kernel/cgroup/cgroup.c:6745 __put_task_struct+0x23/0x100 kernel/fork.c:974 put_task_struct include/linux/sched/task.h:136 [inline] put_task_struct include/linux/sched/task.h:123 [inline] delayed_put_task_struct+0xc5/0xf0 kernel/exit.c:227 rcu_do_batch kernel/rcu/tree.c:2158 [inline] rcu_core+0x380/0x980 kernel/rcu/tree.c:2431 __do_softirq+0x15f/0x421 kernel/softirq.c:553 run_ksoftirqd kernel/softirq.c:921 [inline] run_ksoftirqd+0x31/0x50 kernel/softirq.c:913 smpboot_thread_fn+0x175/0x210 kernel/smpboot.c:164 kthread+0xde/0x110 kernel/kthread.c:388 ret_from_fork+0x2c/0x40 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 to a SOFTIRQ-irq-unsafe lock: (&sighand->siglock){+.+.}-{2:2} ... which became SOFTIRQ-irq-unsafe at: ... lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0xcd/0x2d0 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+0x18b/0x2a0 kernel/ptrace.c:478 __do_sys_ptrace+0xa1/0x150 kernel/ptrace.c:1290 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x40/0xe0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b 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 *** 8 locks held by syz-executor.0/1866: #0: ffff888105ec00c8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x47/0x60 fs/file.c:1177 #1: ffff888103eb43f0 (sb_writers#10){.+.+}-{0:0}, at: ksys_write+0x70/0xf0 fs/read_write.c:637 #2: ffff8881076a8088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0xff/0x1f0 fs/kernfs/file.c:325 #3: ffffffff82583148 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_lock include/linux/cgroup.h:367 [inline] #3: ffffffff82583148 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_lock_and_drain_offline+0x3c/0x3a0 kernel/cgroup/cgroup.c:3079 #4: ffffffff82488150 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2400 [inline] #4: ffffffff82488150 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_update_dfl_csses+0x140/0x2e0 kernel/cgroup/cgroup.c:3037 #5: ffffffff82582fb0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2402 [inline] #5: ffffffff82582fb0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2398 [inline] #5: ffffffff82582fb0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_update_dfl_csses+0x1a9/0x2e0 kernel/cgroup/cgroup.c:3037 #6: ffffffff825830b8 (css_set_lock){..-.}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:376 [inline] #6: ffffffff825830b8 (css_set_lock){..-.}-{2:2}, at: cgroup_migrate_execute+0xb2/0x500 kernel/cgroup/cgroup.c:2553 #7: ffffffff82579140 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:301 [inline] #7: ffffffff82579140 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:747 [inline] #7: ffffffff82579140 (rcu_read_lock){....}-{1:2}, at: __lock_task_sighand+0x24/0x1a0 kernel/signal.c:1405 the dependencies between SOFTIRQ-irq-safe lock and the holding lock: -> (css_set_lock){..-.}-{2:2} { IN-SOFTIRQ-W at: lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0xcd/0x2d0 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+0x35/0xc0 kernel/cgroup/cgroup.c:6745 __put_task_struct+0x23/0x100 kernel/fork.c:974 put_task_struct include/linux/sched/task.h:136 [inline] put_task_struct include/linux/sched/task.h:123 [inline] delayed_put_task_struct+0xc5/0xf0 kernel/exit.c:227 rcu_do_batch kernel/rcu/tree.c:2158 [inline] rcu_core+0x380/0x980 kernel/rcu/tree.c:2431 __do_softirq+0x15f/0x421 kernel/softirq.c:553 run_ksoftirqd kernel/softirq.c:921 [inline] run_ksoftirqd+0x31/0x50 kernel/softirq.c:913 smpboot_thread_fn+0x175/0x210 kernel/smpboot.c:164 kthread+0xde/0x110 kernel/kthread.c:388 ret_from_fork+0x2c/0x40 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 INITIAL USE at: lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0xcd/0x2d0 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+0x23d/0x390 kernel/cgroup/cgroup.c:2125 cgroup_init+0x116/0x460 kernel/cgroup/cgroup.c:6119 start_kernel+0x4eb/0x580 init/main.c:1063 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:555 x86_64_start_kernel+0xad/0xc0 arch/x86/kernel/head64.c:536 secondary_startup_64_no_verify+0x166/0x16b } ... key at: [] css_set_lock+0x18/0x40 the dependencies between the lock to be acquired and SOFTIRQ-irq-unsafe lock: -> (&sighand->siglock){+.+.}-{2:2} { HARDIRQ-ON-W at: lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0xcd/0x2d0 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+0x18b/0x2a0 kernel/ptrace.c:478 __do_sys_ptrace+0xa1/0x150 kernel/ptrace.c:1290 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x40/0xe0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b SOFTIRQ-ON-W at: lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0xcd/0x2d0 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+0x18b/0x2a0 kernel/ptrace.c:478 __do_sys_ptrace+0xa1/0x150 kernel/ptrace.c:1290 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x40/0xe0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b INITIAL USE at: lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0xcd/0x2d0 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+0x1a/0x30 kernel/signal.c:197 ret_from_fork+0x16/0x40 arch/x86/kernel/process.c:143 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 } ... key at: [] __key.272+0x0/0x10 ... acquired at: lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0xcd/0x2d0 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 __lock_task_sighand+0x67/0x1a0 kernel/signal.c:1422 lock_task_sighand include/linux/sched/signal.h:745 [inline] cgroup_freeze_task+0x2b/0xa0 kernel/cgroup/freezer.c:160 cgroup_migrate_execute+0x15d/0x500 kernel/cgroup/cgroup.c:2567 cgroup_update_dfl_csses+0x27c/0x2e0 kernel/cgroup/cgroup.c:3055 cgroup_apply_control kernel/cgroup/cgroup.c:3295 [inline] cgroup_subtree_control_write+0x3ea/0x430 kernel/cgroup/cgroup.c:3440 kernfs_fop_write_iter+0x149/0x1f0 fs/kernfs/file.c:334 call_write_iter include/linux/fs.h:2020 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x25b/0x4f0 fs/read_write.c:584 ksys_write+0x70/0xf0 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x40/0xe0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b stack backtrace: CPU: 0 PID: 1866 Comm: syz-executor.0 Not tainted 6.7.0-rc1-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+0x5c/0xb0 lib/dump_stack.c:106 print_bad_irq_dependency kernel/locking/lockdep.c:2626 [inline] check_irq_usage+0x805/0x940 kernel/locking/lockdep.c:2865 check_prev_add kernel/locking/lockdep.c:3138 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3868 [inline] __lock_acquire+0x12d9/0x1ab0 kernel/locking/lockdep.c:5136 lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0xcd/0x2d0 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 __lock_task_sighand+0x67/0x1a0 kernel/signal.c:1422 lock_task_sighand include/linux/sched/signal.h:745 [inline] cgroup_freeze_task+0x2b/0xa0 kernel/cgroup/freezer.c:160 cgroup_migrate_execute+0x15d/0x500 kernel/cgroup/cgroup.c:2567 cgroup_update_dfl_csses+0x27c/0x2e0 kernel/cgroup/cgroup.c:3055 cgroup_apply_control kernel/cgroup/cgroup.c:3295 [inline] cgroup_subtree_control_write+0x3ea/0x430 kernel/cgroup/cgroup.c:3440 kernfs_fop_write_iter+0x149/0x1f0 fs/kernfs/file.c:334 call_write_iter include/linux/fs.h:2020 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x25b/0x4f0 fs/read_write.c:584 ksys_write+0x70/0xf0 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x40/0xe0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x7fe5ef941ae9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fe5ef4c40c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fe5efa60f80 RCX: 00007fe5ef941ae9 RDX: 0000000000000006 RSI: 0000000020000100 RDI: 0000000000000004 RBP: 00007fe5ef98d47a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000006 R14: 00007fe5efa60f80 R15: 00007ffd081e1a08