====================================================== WARNING: possible circular locking dependency detected 5.15.163-syzkaller #0 Not tainted ------------------------------------------------------ syz.1.252/4521 is trying to acquire lock: ffff888075670a28 (&p->pi_lock){-.-.}-{2:2}, at: try_to_wake_up+0xae/0x1300 kernel/sched/core.c:4030 but task is already holding lock: ffffffff8c7fc378 ((console_sem).lock){-...}-{2:2}, at: up+0x19/0x90 kernel/locking/semaphore.c:186 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 ((console_sem).lock){-...}-{2:2}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __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:138 __down_trylock_console_sem+0x105/0x250 kernel/printk/printk.c:239 console_trylock kernel/printk/printk.c:2575 [inline] console_trylock_spinning+0x8a/0x3f0 kernel/printk/printk.c:1867 vprintk_emit+0xa6/0x150 kernel/printk/printk.c:2273 _printk+0xd1/0x120 kernel/printk/printk.c:2299 fail_dump lib/fault-inject.c:45 [inline] should_fail+0x36c/0x4c0 lib/fault-inject.c:146 __copy_to_user_inatomic include/linux/uaccess.h:133 [inline] copy_to_user_nofault+0xdd/0x1c0 mm/maccess.c:255 0xffffffffa0016117 bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline] __bpf_prog_run include/linux/filter.h:628 [inline] bpf_prog_run include/linux/filter.h:635 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:1880 [inline] bpf_trace_run3+0x1d1/0x380 kernel/trace/bpf_trace.c:1918 __traceiter_sched_switch+0x7d/0xb0 include/trace/events/sched.h:220 trace_sched_switch include/trace/events/sched.h:220 [inline] __schedule+0x1e8d/0x45b0 kernel/sched/core.c:6373 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6780 irqentry_exit+0x53/0x80 kernel/entry/common.c:432 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:643 vfs_write+0x30f/0xe50 fs/read_write.c:592 ksys_write+0x1a2/0x2c0 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #1 (&rq->__lock){-.-.}-{2:2}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 _raw_spin_lock_nested+0x2d/0x40 kernel/locking/spinlock.c:368 raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475 raw_spin_rq_lock kernel/sched/sched.h:1326 [inline] rq_lock kernel/sched/sched.h:1621 [inline] task_fork_fair+0x5d/0x350 kernel/sched/fair.c:11495 sched_cgroup_fork+0x2d3/0x330 kernel/sched/core.c:4466 copy_process+0x224a/0x3ef0 kernel/fork.c:2320 kernel_clone+0x210/0x960 kernel/fork.c:2604 kernel_thread+0x168/0x1e0 kernel/fork.c:2656 rest_init+0x21/0x330 init/main.c:706 start_kernel+0x48c/0x540 init/main.c:1140 secondary_startup_64_no_verify+0xb1/0xbb -> #0 (&p->pi_lock){-.-.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __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+0xae/0x1300 kernel/sched/core.c:4030 up+0x6e/0x90 kernel/locking/semaphore.c:190 __up_console_sem+0x11a/0x1e0 kernel/printk/printk.c:256 console_unlock+0x1145/0x12b0 kernel/printk/printk.c:2760 do_con_write+0x718a/0x7270 drivers/tty/vt/vt.c:2965 con_write+0x20/0x40 drivers/tty/vt/vt.c:3295 process_output_block drivers/tty/n_tty.c:592 [inline] n_tty_write+0xd7e/0x1280 drivers/tty/n_tty.c:2339 do_tty_write drivers/tty/tty_io.c:1038 [inline] file_tty_write+0x561/0x920 drivers/tty/tty_io.c:1110 call_write_iter include/linux/fs.h:2172 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0xacd/0xe50 fs/read_write.c:594 ksys_write+0x1a2/0x2c0 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 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 *** 5 locks held by syz.1.252/4521: #0: ffff88807d15f098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252 #1: ffff88807d15f130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: tty_write_lock drivers/tty/tty_io.c:961 [inline] #1: ffff88807d15f130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: do_tty_write drivers/tty/tty_io.c:984 [inline] #1: ffff88807d15f130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: file_tty_write+0x24f/0x920 drivers/tty/tty_io.c:1110 #2: ffff88807d15f2e8 (&tty->termios_rwsem){++++}-{3:3}, at: n_tty_write+0x252/0x1280 drivers/tty/n_tty.c:2322 #3: ffffc9000136e378 (&ldata->output_lock){+.+.}-{3:3}, at: process_output_block drivers/tty/n_tty.c:547 [inline] #3: ffffc9000136e378 (&ldata->output_lock){+.+.}-{3:3}, at: n_tty_write+0x6b9/0x1280 drivers/tty/n_tty.c:2339 #4: ffffffff8c7fc378 ((console_sem).lock){-...}-{2:2}, at: up+0x19/0x90 kernel/locking/semaphore.c:186 stack backtrace: CPU: 0 PID: 4521 Comm: syz.1.252 Not tainted 5.15.163-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106 check_noncircular+0x2f8/0x3b0 kernel/locking/lockdep.c:2133 check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __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+0xae/0x1300 kernel/sched/core.c:4030 up+0x6e/0x90 kernel/locking/semaphore.c:190 __up_console_sem+0x11a/0x1e0 kernel/printk/printk.c:256 console_unlock+0x1145/0x12b0 kernel/printk/printk.c:2760 do_con_write+0x718a/0x7270 drivers/tty/vt/vt.c:2965 con_write+0x20/0x40 drivers/tty/vt/vt.c:3295 process_output_block drivers/tty/n_tty.c:592 [inline] n_tty_write+0xd7e/0x1280 drivers/tty/n_tty.c:2339 do_tty_write drivers/tty/tty_io.c:1038 [inline] file_tty_write+0x561/0x920 drivers/tty/tty_io.c:1110 call_write_iter include/linux/fs.h:2172 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0xacd/0xe50 fs/read_write.c:594 ksys_write+0x1a2/0x2c0 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f6a4f99fb59 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:00007f6a4e3ff048 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f6a4fb30038 RCX: 00007f6a4f99fb59 RDX: 0000000000001006 RSI: 0000000020001080 RDI: 0000000000000008 RBP: 00007f6a4fa0ee5d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000006e R14: 00007f6a4fb30038 R15: 00007ffe28a95488