====================================================== WARNING: possible circular locking dependency detected 6.1.129-syzkaller #0 Not tainted ------------------------------------------------------ syz.4.500/6410 is trying to acquire lock: ffff88807a5d27d8 (&p->pi_lock){-.-.}-{2:2}, at: try_to_wake_up+0xad/0x1250 kernel/sched/core.c:4110 but task is already holding lock: ffffffff8d20a538 ((console_sem).lock){-...}-{2:2}, at: up+0x19/0x90 kernel/locking/semaphore.c:187 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 ((console_sem).lock){-...}-{2:2}: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 down_trylock+0x1c/0xa0 kernel/locking/semaphore.c:139 __down_trylock_console_sem+0x105/0x250 kernel/printk/printk.c:243 console_trylock kernel/printk/printk.c:2650 [inline] console_trylock_spinning kernel/printk/printk.c:1896 [inline] vprintk_emit+0x1ee/0x740 kernel/printk/printk.c:2302 _printk+0xd1/0x111 kernel/printk/printk.c:2328 fail_dump lib/fault-inject.c:45 [inline] should_fail_ex+0x387/0x4d0 lib/fault-inject.c:147 strncpy_from_user+0x32/0x360 lib/strncpy_from_user.c:118 strncpy_from_user_nofault+0x6c/0x130 mm/maccess.c:186 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:204 [inline] ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:310 [inline] bpf_probe_read_compat_str+0xe4/0x180 kernel/trace/bpf_trace.c:306 0xffffffffa0001ff1 bpf_dispatcher_nop_func include/linux/bpf.h:1000 [inline] __bpf_prog_run include/linux/filter.h:603 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline] bpf_trace_run4+0x253/0x470 kernel/trace/bpf_trace.c:2325 __traceiter_sched_switch+0x91/0xc0 include/trace/events/sched.h:222 trace_sched_switch include/trace/events/sched.h:222 [inline] __schedule+0x2128/0x4570 kernel/sched/core.c:6557 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6872 irqentry_exit+0x53/0x80 kernel/entry/common.c:439 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:696 __sanitizer_cov_trace_pc+0x4/0x60 kernel/kcov.c:212 __get_task_ioprio+0xa2/0x240 block/ioprio.c:153 get_current_ioprio include/linux/ioprio.h:60 [inline] init_sync_kiocb include/linux/fs.h:2417 [inline] seq_read+0x16e/0x380 fs/seq_file.c:158 pde_read fs/proc/inode.c:316 [inline] proc_reg_read+0x1f9/0x2e0 fs/proc/inode.c:328 vfs_read+0x2ed/0xbf0 fs/read_write.c:468 ksys_pread64 fs/read_write.c:665 [inline] __do_sys_pread64 fs/read_write.c:675 [inline] __se_sys_pread64 fs/read_write.c:672 [inline] __x64_sys_pread64+0x1a6/0x230 fs/read_write.c:672 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #1 (&rq->__lock){-.-.}-{2:2}: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 _raw_spin_lock_nested+0x2d/0x40 kernel/locking/spinlock.c:378 raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537 raw_spin_rq_lock kernel/sched/sched.h:1355 [inline] rq_lock kernel/sched/sched.h:1645 [inline] task_fork_fair+0x5d/0x350 kernel/sched/fair.c:11886 sched_cgroup_fork+0x374/0x400 kernel/sched/core.c:4684 copy_process+0x2482/0x40a0 kernel/fork.c:2383 kernel_clone+0x222/0x920 kernel/fork.c:2681 user_mode_thread+0x140/0x1b0 kernel/fork.c:2757 rest_init+0x23/0x300 init/main.c:698 start_kernel+0x0/0x53f init/main.c:893 start_kernel+0x496/0x53f init/main.c:1140 secondary_startup_64_no_verify+0xcf/0xdb -> #0 (&p->pi_lock){-.-.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 try_to_wake_up+0xad/0x1250 kernel/sched/core.c:4110 up+0x6e/0x90 kernel/locking/semaphore.c:191 __up_console_sem+0x11a/0x1e0 kernel/printk/printk.c:260 __console_unlock kernel/printk/printk.c:2697 [inline] console_unlock+0x591/0x7c0 kernel/printk/printk.c:2908 vt_k_ioctl drivers/tty/vt/vt_ioctl.c:382 [inline] vt_ioctl+0x6be/0x1d10 drivers/tty/vt/vt_ioctl.c:752 tty_ioctl+0x7f9/0xbd0 drivers/tty/tty_io.c:2776 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 other info that might help us debug this: Chain exists of: &p->pi_lock --> &rq->__lock --> (console_sem).lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock((console_sem).lock); lock(&rq->__lock); lock((console_sem).lock); lock(&p->pi_lock); *** DEADLOCK *** 1 lock held by syz.4.500/6410: #0: ffffffff8d20a538 ((console_sem).lock){-...}-{2:2}, at: up+0x19/0x90 kernel/locking/semaphore.c:187 stack backtrace: CPU: 1 PID: 6410 Comm: syz.4.500 Not tainted 6.1.129-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 check_noncircular+0x2fa/0x3b0 kernel/locking/lockdep.c:2170 check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 try_to_wake_up+0xad/0x1250 kernel/sched/core.c:4110 up+0x6e/0x90 kernel/locking/semaphore.c:191 __up_console_sem+0x11a/0x1e0 kernel/printk/printk.c:260 __console_unlock kernel/printk/printk.c:2697 [inline] console_unlock+0x591/0x7c0 kernel/printk/printk.c:2908 vt_k_ioctl drivers/tty/vt/vt_ioctl.c:382 [inline] vt_ioctl+0x6be/0x1d10 drivers/tty/vt/vt_ioctl.c:752 tty_ioctl+0x7f9/0xbd0 drivers/tty/tty_io.c:2776 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f4c04f8d169 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f4c04dbd038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f4c051a6240 RCX: 00007f4c04f8d169 RDX: 0000000000000000 RSI: 0000000000004b3a RDI: 0000000000000008 RBP: 00007f4c0500e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f4c051a6240 R15: 00007fff9ac57648