------------[ cut here ]------------ ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.3.3209/16262 is trying to acquire lock: ffffffff8e126620 (console_owner){-.-.}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:339 [inline] ffffffff8e126620 (console_owner){-.-.}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:232 [inline] ffffffff8e126620 (console_owner){-.-.}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:292 [inline] ffffffff8e126620 (console_owner){-.-.}-{0:0}, at: console_flush_all+0x10b/0xcf0 kernel/printk/printk.c:2992 but task is already holding lock: ffff8880b8c3c258 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x9c/0x130 kernel/sched/core.c:578 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&rq->__lock){-.-.}-{2:2}: _raw_spin_lock_nested+0x32/0x50 kernel/locking/spinlock.c:378 raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:570 raw_spin_rq_lock kernel/sched/sched.h:1380 [inline] rq_lock kernel/sched/sched.h:1689 [inline] task_fork_fair+0x62/0x1f0 kernel/sched/fair.c:12738 sched_cgroup_fork+0x352/0x3e0 kernel/sched/core.c:4829 copy_process+0x21fd/0x3da0 kernel/fork.c:2619 kernel_clone+0x24b/0x8a0 kernel/fork.c:2919 user_mode_thread+0x111/0x180 kernel/fork.c:2997 rest_init+0x27/0x300 init/main.c:675 arch_call_rest_init+0xe/0x10 init/main.c:806 start_kernel+0x461/0x4e0 init/main.c:1051 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555 copy_bootdata+0x0/0xd0 arch/x86/kernel/head64.c:536 secondary_startup_64_no_verify+0x179/0x17b -> #3 (&p->pi_lock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xb4/0x100 kernel/locking/spinlock.c:162 class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:523 [inline] try_to_wake_up+0x5b/0x10e0 kernel/sched/core.c:4244 __wake_up_common+0x28e/0x4d0 kernel/sched/wait.c:107 __wake_up_common_lock kernel/sched/wait.c:138 [inline] __wake_up+0x125/0x1a0 kernel/sched/wait.c:160 tty_port_default_wakeup+0xa2/0xf0 drivers/tty/tty_port.c:69 serial8250_tx_chars+0x6a2/0x8b0 drivers/tty/serial/8250/8250_port.c:1837 serial8250_handle_irq+0x6c3/0x8c0 drivers/tty/serial/8250/8250_port.c:1951 serial8250_default_handle_irq+0xb8/0x1a0 drivers/tty/serial/8250/8250_port.c:1971 serial8250_interrupt+0x9f/0x1c0 drivers/tty/serial/8250/8250_core.c:127 __handle_irq_event_percpu+0x271/0x940 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:210 handle_edge_irq+0x246/0xb20 kernel/irq/chip.c:831 generic_handle_irq_desc include/linux/irqdesc.h:161 [inline] handle_irq arch/x86/kernel/irq.c:240 [inline] __common_interrupt+0x13b/0x230 arch/x86/kernel/irq.c:259 common_interrupt+0xb4/0xd0 arch/x86/kernel/irq.c:249 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:678 native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:147 arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:753 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97 cpuidle_idle_call kernel/sched/idle.c:178 [inline] do_idle+0x334/0x5c0 kernel/sched/idle.c:302 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:401 start_secondary+0xee/0xf0 arch/x86/kernel/smpboot.c:323 secondary_startup_64_no_verify+0x179/0x17b -> #2 (&tty->write_wait){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xb4/0x100 kernel/locking/spinlock.c:162 __wake_up_common_lock kernel/sched/wait.c:137 [inline] __wake_up+0x10b/0x1a0 kernel/sched/wait.c:160 tty_port_default_wakeup+0xa2/0xf0 drivers/tty/tty_port.c:69 serial8250_tx_chars+0x6a2/0x8b0 drivers/tty/serial/8250/8250_port.c:1837 serial8250_handle_irq+0x6c3/0x8c0 drivers/tty/serial/8250/8250_port.c:1951 serial8250_default_handle_irq+0xb8/0x1a0 drivers/tty/serial/8250/8250_port.c:1971 serial8250_interrupt+0x9f/0x1c0 drivers/tty/serial/8250/8250_core.c:127 __handle_irq_event_percpu+0x271/0x940 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:210 handle_edge_irq+0x246/0xb20 kernel/irq/chip.c:831 generic_handle_irq_desc include/linux/irqdesc.h:161 [inline] handle_irq arch/x86/kernel/irq.c:240 [inline] __common_interrupt+0x13b/0x230 arch/x86/kernel/irq.c:259 common_interrupt+0xb4/0xd0 arch/x86/kernel/irq.c:249 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:678 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0xc0/0x120 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] uart_write+0x45b/0x5d0 drivers/tty/serial/serial_core.c:634 process_output_block drivers/tty/n_tty.c:580 [inline] n_tty_write+0xd3d/0x11e0 drivers/tty/n_tty.c:2395 iterate_tty_write drivers/tty/tty_io.c:1019 [inline] file_tty_write+0x529/0x960 drivers/tty/tty_io.c:1090 call_write_iter include/linux/fs.h:2019 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x474/0x9a0 fs/read_write.c:584 ksys_write+0x151/0x260 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #1 (&port_lock_key){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xb4/0x100 kernel/locking/spinlock.c:162 serial8250_console_write+0x181/0x18b0 drivers/tty/serial/8250/8250_port.c:3446 console_emit_next_record kernel/printk/printk.c:2944 [inline] console_flush_all+0x6ad/0xcf0 kernel/printk/printk.c:3000 console_unlock+0xad/0x350 kernel/printk/printk.c:3069 vprintk_emit+0x497/0x610 kernel/printk/printk.c:2341 _printk+0xde/0x130 kernel/printk/printk.c:2366 register_console+0xb96/0xf00 kernel/printk/printk.c:3583 univ8250_console_init+0x45/0x50 drivers/tty/serial/8250/8250_core.c:717 console_init+0x17b/0x5d0 kernel/printk/printk.c:3726 start_kernel+0x2c8/0x4e0 init/main.c:987 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555 copy_bootdata+0x0/0xd0 arch/x86/kernel/head64.c:536 secondary_startup_64_no_verify+0x179/0x17b -> #0 (console_owner){-.-.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3162 [inline] check_prevs_add kernel/locking/lockdep.c:3281 [inline] validate_chain kernel/locking/lockdep.c:3897 [inline] __lock_acquire+0x3a07/0x7eb0 kernel/locking/lockdep.c:5171 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5790 console_lock_spinning_enable kernel/printk/printk.c:1871 [inline] console_emit_next_record kernel/printk/printk.c:2938 [inline] console_flush_all+0x676/0xcf0 kernel/printk/printk.c:3000 console_unlock+0xad/0x350 kernel/printk/printk.c:3069 vprintk_emit+0x497/0x610 kernel/printk/printk.c:2341 _printk+0xde/0x130 kernel/printk/printk.c:2366 __report_bug lib/bug.c:195 [inline] report_bug+0x34e/0x4f0 lib/bug.c:219 handle_bug+0xcf/0x120 arch/x86/kernel/traps.c:310 exc_invalid_op+0x1a/0x50 arch/x86/kernel/traps.c:345 asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:606 update_rq_clock+0x32e/0x4b0 kernel/sched/core.c:783 pick_next_task kernel/sched/core.c:6200 [inline] __schedule+0x2ca1/0x4700 kernel/sched/core.c:6684 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6889 preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6913 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] zap_pte_range mm/memory.c:1523 [inline] zap_pmd_range mm/memory.c:1571 [inline] zap_pud_range mm/memory.c:1600 [inline] zap_p4d_range mm/memory.c:1621 [inline] unmap_page_range+0x2577/0x32f0 mm/memory.c:1642 unmap_vmas+0x286/0x3f0 mm/memory.c:1732 exit_mmap+0x238/0xb90 mm/mmap.c:3310 __mmput+0x118/0x3a0 kernel/fork.c:1362 exit_mm+0x23f/0x340 kernel/exit.c:576 do_exit+0x909/0x2530 kernel/exit.c:877 do_group_exit+0x22d/0x2f0 kernel/exit.c:1032 get_signal+0x12a6/0x1390 kernel/signal.c:2927 arch_do_signal_or_restart+0xc2/0x7b0 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:213 __syscall_exit_to_user_mode_work kernel/entry/common.c:294 [inline] syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:305 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 other info that might help us debug this: Chain exists of: console_owner --> &p->pi_lock --> &rq->__lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&rq->__lock); lock(&p->pi_lock); lock(&rq->__lock); lock(console_owner); *** DEADLOCK *** 5 locks held by syz.3.3209/16262: #0: ffff888020b94da0 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock include/linux/mmap_lock.h:146 [inline] #0: ffff888020b94da0 (&mm->mmap_lock){++++}-{3:3}, at: exit_mmap+0x182/0xb90 mm/mmap.c:3295 #1: ffffffff8e1322e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #1: ffffffff8e1322e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #1: ffffffff8e1322e0 (rcu_read_lock){....}-{1:2}, at: __pte_offset_map+0x2c/0x280 mm/pgtable-generic.c:287 #2: ffff8880b8c3c258 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x9c/0x130 kernel/sched/core.c:578 #3: ffffffff8e126700 (console_lock){+.+.}-{0:0}, at: _printk+0xde/0x130 kernel/printk/printk.c:2366 #4: ffffffff8e00df10 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:339 [inline] #4: ffffffff8e00df10 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:232 [inline] #4: ffffffff8e00df10 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:292 [inline] #4: ffffffff8e00df10 (console_srcu){....}-{0:0}, at: console_flush_all+0x10b/0xcf0 kernel/printk/printk.c:2992 stack backtrace: CPU: 0 PID: 16262 Comm: syz.3.3209 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 check_noncircular+0x2fc/0x400 kernel/locking/lockdep.c:2215 check_prev_add kernel/locking/lockdep.c:3162 [inline] check_prevs_add kernel/locking/lockdep.c:3281 [inline] validate_chain kernel/locking/lockdep.c:3897 [inline] __lock_acquire+0x3a07/0x7eb0 kernel/locking/lockdep.c:5171 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5790 console_lock_spinning_enable kernel/printk/printk.c:1871 [inline] console_emit_next_record kernel/printk/printk.c:2938 [inline] console_flush_all+0x676/0xcf0 kernel/printk/printk.c:3000 console_unlock+0xad/0x350 kernel/printk/printk.c:3069 vprintk_emit+0x497/0x610 kernel/printk/printk.c:2341 _printk+0xde/0x130 kernel/printk/printk.c:2366 __report_bug lib/bug.c:195 [inline] report_bug+0x34e/0x4f0 lib/bug.c:219 handle_bug+0xcf/0x120 arch/x86/kernel/traps.c:310 exc_invalid_op+0x1a/0x50 arch/x86/kernel/traps.c:345 asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:606 RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1371 [inline] RIP: 0010:update_rq_clock+0x32e/0x4b0 kernel/sched/core.c:767 Code: 00 00 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 b4 96 83 00 48 01 2b 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d c3 <0f> 0b e9 62 fd ff ff 48 89 df 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 RSP: 0018:ffffc900042c7120 EFLAGS: 00010046 RAX: 0000000000000000 RBX: ffff8880b8d3c240 RCX: 4c47a1b8d4b2c100 RDX: 0000000000000003 RSI: ffffffff8aeae2c0 RDI: ffffffff8b3c50e0 RBP: ffffc900042c7370 R08: ffff888022ee9027 R09: 0000000000000001 R10: ffff888022ee9018 R11: ffffed10045dd205 R12: ffffffff8ccbca38 R13: dffffc0000000000 R14: ffff8880b8d3cf88 R15: ffff8880b8d3c240 pick_next_task kernel/sched/core.c:6200 [inline] __schedule+0x2ca1/0x4700 kernel/sched/core.c:6684 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6889 preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6913 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] zap_pte_range mm/memory.c:1523 [inline] zap_pmd_range mm/memory.c:1571 [inline] zap_pud_range mm/memory.c:1600 [inline] zap_p4d_range mm/memory.c:1621 [inline] unmap_page_range+0x2577/0x32f0 mm/memory.c:1642 unmap_vmas+0x286/0x3f0 mm/memory.c:1732 exit_mmap+0x238/0xb90 mm/mmap.c:3310 __mmput+0x118/0x3a0 kernel/fork.c:1362 exit_mm+0x23f/0x340 kernel/exit.c:576 do_exit+0x909/0x2530 kernel/exit.c:877 do_group_exit+0x22d/0x2f0 kernel/exit.c:1032 get_signal+0x12a6/0x1390 kernel/signal.c:2927 arch_do_signal_or_restart+0xc2/0x7b0 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:213 __syscall_exit_to_user_mode_work kernel/entry/common.c:294 [inline] syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:305 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fa61c19f559 Code: Unable to access opcode bytes at 0x7fa61c19f52f. RSP: 002b:00007fa61a3d50e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fa61c426188 RCX: 00007fa61c19f559 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fa61c426188 RBP: 00007fa61c426180 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa61c426218 R14: 00007ffc9e9c66f0 R15: 00007ffc9e9c67d8 WARNING: CPU: 0 PID: 16262 at kernel/sched/sched.h:1371 update_rq_clock+0x32e/0x4b0 kernel/sched/core.c:783 Modules linked in: CPU: 0 PID: 16262 Comm: syz.3.3209 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1371 [inline] RIP: 0010:update_rq_clock+0x32e/0x4b0 kernel/sched/core.c:767 Code: 00 00 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 b4 96 83 00 48 01 2b 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d c3 <0f> 0b e9 62 fd ff ff 48 89 df 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 RSP: 0018:ffffc900042c7120 EFLAGS: 00010046 RAX: 0000000000000000 RBX: ffff8880b8d3c240 RCX: 4c47a1b8d4b2c100 RDX: 0000000000000003 RSI: ffffffff8aeae2c0 RDI: ffffffff8b3c50e0 RBP: ffffc900042c7370 R08: ffff888022ee9027 R09: 0000000000000001 R10: ffff888022ee9018 R11: ffffed10045dd205 R12: ffffffff8ccbca38 R13: dffffc0000000000 R14: ffff8880b8d3cf88 R15: ffff8880b8d3c240 FS: 0000000000000000(0000) GS:ffff8880b8c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f659bb1d943 CR3: 000000007cfda000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000001800 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: pick_next_task kernel/sched/core.c:6200 [inline] __schedule+0x2ca1/0x4700 kernel/sched/core.c:6684 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6889 preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6913 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] zap_pte_range mm/memory.c:1523 [inline] zap_pmd_range mm/memory.c:1571 [inline] zap_pud_range mm/memory.c:1600 [inline] zap_p4d_range mm/memory.c:1621 [inline] unmap_page_range+0x2577/0x32f0 mm/memory.c:1642 unmap_vmas+0x286/0x3f0 mm/memory.c:1732 exit_mmap+0x238/0xb90 mm/mmap.c:3310 __mmput+0x118/0x3a0 kernel/fork.c:1362 exit_mm+0x23f/0x340 kernel/exit.c:576 do_exit+0x909/0x2530 kernel/exit.c:877 do_group_exit+0x22d/0x2f0 kernel/exit.c:1032 get_signal+0x12a6/0x1390 kernel/signal.c:2927 arch_do_signal_or_restart+0xc2/0x7b0 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:213 __syscall_exit_to_user_mode_work kernel/entry/common.c:294 [inline] syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:305 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fa61c19f559 Code: Unable to access opcode bytes at 0x7fa61c19f52f. RSP: 002b:00007fa61a3d50e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fa61c426188 RCX: 00007fa61c19f559 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fa61c426188 RBP: 00007fa61c426180 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa61c426218 R14: 00007ffc9e9c66f0 R15: 00007ffc9e9c67d8