* [thomas-weissschuh:b4/auxclock-nanosleep] aafb55d8d1: WARNING:possible_circular_locking_dependency_detected
@ 2026-02-26 12:42 kernel test robot
2026-02-26 12:46 ` Thomas Weißschuh
0 siblings, 1 reply; 3+ messages in thread
From: kernel test robot @ 2026-02-26 12:42 UTC (permalink / raw)
To: linux+lkp; +Cc: oe-lkp, lkp, oliver.sang
Hello,
again, since we are not sure the purpose of this patch, we make out this report
again. if low value or you don't need this check, please let us know. thanks
kernel test robot noticed "WARNING:possible_circular_locking_dependency_detected" on:
commit: aafb55d8d1bf7d9b1151e988d81b0f70b81ec76c ("count wakeups")
https://git.kernel.org/cgit/linux/kernel/git/thomas.weissschuh/linux.git b4/auxclock-nanosleep
in testcase: boot
config: i386-randconfig-054-20260223
compiler: clang-20
test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 32G
(please refer to attached dmesg/kmsg for entire log/backtrace)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202602262005.2ceb43cb-lkp@intel.com
[ 10.361682][ T1] WARNING: possible circular locking dependency detected
[ 10.362400][ T1] 7.0.0-rc1-00006-gaafb55d8d1bf #1 Not tainted
[ 10.363043][ T1] ------------------------------------------------------
[ 10.363756][ T1] systemd/1 is trying to acquire lock:
[ 10.364318][ T1] c0ceccc4 (&dev->power.lock){....}-{3:3}, at: __pm_runtime_resume (drivers/base/power/runtime.c:?)
[ 10.365221][ T1]
[ 10.365221][ T1] but task is already holding lock:
[ 10.365973][ T1] c2bb2f60 (&port_lock_key){-...}-{3:3}, at: uart_port_ref_lock (include/linux/serial_core.h:717)
[ 10.366865][ T1]
[ 10.366865][ T1] which lock already depends on the new lock.
[ 10.366865][ T1]
[ 10.367927][ T1]
[ 10.367927][ T1] the existing dependency chain (in reverse order) is:
[ 10.368840][ T1]
[ 10.368840][ T1] -> #3 (&port_lock_key){-...}-{3:3}:
[ 10.369608][ T1] _raw_spin_lock_irqsave (include/linux/spinlock_api_smp.h:132 kernel/locking/spinlock.c:162)
[ 10.370198][ T1] serial8250_console_write (include/linux/serial_core.h:?)
[ 10.370820][ T1] univ8250_console_write (drivers/tty/serial/8250/8250_core.c:399)
[ 10.371411][ T1] console_flush_all (kernel/printk/printk.c:3184)
[ 10.371971][ T1] console_unlock (kernel/printk/printk.c:3373 kernel/printk/printk.c:3413)
[ 10.372495][ T1] vprintk_emit (arch/x86/include/asm/preempt.h:95 kernel/printk/printk.c:2480)
[ 10.373004][ T1] vprintk_default (kernel/printk/printk.c:2494)
[ 10.373530][ T1] vprintk (kernel/printk/printk_safe.c:82)
[ 10.373977][ T1] _printk (kernel/printk/printk.c:2507)
[ 10.374439][ T1] register_console (kernel/printk/printk.c:4208)
[ 10.375012][ T1] univ8250_console_init (drivers/tty/serial/8250/8250_core.c:?)
[ 10.375596][ T1] console_init (arch/x86/include/asm/jump_label.h:37 include/trace/events/initcall.h:48 kernel/printk/printk.c:4408)
[ 10.376115][ T1] start_kernel (init/main.c:1148)
[ 10.376640][ T1] i386_start_kernel (arch/x86/kernel/head32.c:79)
[ 10.377194][ T1] startup_32_smp (arch/x86/kernel/head_32.S:293)
[ 10.377730][ T1]
[ 10.377730][ T1] -> #2 (console_owner){-...}-{0:0}:
[ 10.378500][ T1] console_lock_spinning_enable (kernel/printk/printk.c:1902)
[ 10.379156][ T1] console_flush_all (kernel/printk/printk.c:3182)
[ 10.379720][ T1] console_unlock (kernel/printk/printk.c:3373 kernel/printk/printk.c:3413)
[ 10.380242][ T1] vprintk_emit (arch/x86/include/asm/preempt.h:95 kernel/printk/printk.c:2480)
[ 10.380756][ T1] vprintk_default (kernel/printk/printk.c:2494)
[ 10.381294][ T1] vprintk (kernel/printk/printk_safe.c:82)
[ 10.381739][ T1] _printk (kernel/printk/printk.c:2507)
[ 10.382203][ T1] __hrtimer_run_queues (kernel/time/hrtimer.c:1826)
[ 10.382783][ T1] hrtimer_run_queues (kernel/time/hrtimer.c:2011)
[ 10.389262][ T1] update_process_times (kernel/time/timer.c:2455)
[ 10.389835][ T1] tick_periodic (kernel/time/tick-common.c:102)
[ 10.390358][ T1] tick_handle_periodic (include/linux/clockchips.h:152 kernel/time/tick-common.c:123)
[ 10.390985][ T1] __sysvec_apic_timer_interrupt (arch/x86/include/asm/jump_label.h:37 arch/x86/include/asm/trace/irq_vectors.h:40 arch/x86/kernel/apic/apic.c:1063)
[ 10.391674][ T1] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1056 arch/x86/kernel/apic/apic.c:1056)
[ 10.392321][ T1] handle_exception_return (arch/x86/entry/entry_32.S:1055)
[ 10.392917][ T1] seqcount_lockdep_reader_access (arch/x86/include/asm/irqflags.h:158)
[ 10.393582][ T1] d_alloc_parallel (include/linux/seqlock.h:228)
[ 10.394144][ T1] __lookup_slow (include/linux/err.h:78)
[ 10.394714][ T1] lookup_slow (fs/namei.c:1933)
[ 10.395229][ T1] path_lookupat (fs/namei.c:2279)
[ 10.395758][ T1] filename_lookup (fs/namei.c:2833)
[ 10.396308][ T1] kern_path (fs/namei.c:3040)
[ 10.396795][ T1] init_stat (fs/init.c:149)
[ 10.397286][ T1] clean_path (init/initramfs.c:337)
[ 10.397776][ T1] do_name (init/initramfs.c:379)
[ 10.398256][ T1] flush_buffer (init/initramfs.c:470 init/initramfs.c:482)
[ 10.398827][ T1] __gunzip (lib/decompress_inflate.c:161)
[ 10.399345][ T1] gunzip (lib/decompress_inflate.c:207)
[ 10.399806][ T1] unpack_to_rootfs (init/initramfs.c:551)
[ 10.400380][ T1] do_populate_rootfs (init/initramfs.c:734)
[ 10.400958][ T1] async_run_entry_fn (kernel/async.c:136)
[ 10.401540][ T1] process_one_work (kernel/workqueue.c:3280)
[ 10.402107][ T1] worker_thread (kernel/workqueue.c:3352 kernel/workqueue.c:3439)
[ 10.402695][ T1] kthread (kernel/kthread.c:469)
[ 10.403191][ T1] ret_from_fork (arch/x86/kernel/process.c:164)
[ 10.403729][ T1] ret_from_fork_asm (arch/x86/entry/entry_32.S:737)
[ 10.404302][ T1] restore_all_switch_stack (arch/x86/entry/entry_32.S:945)
[ 10.404940][ T1]
[ 10.404940][ T1] -> #1 (hrtimer_bases.lock){-.-.}-{2:2}:
[ 10.405824][ T1] _raw_spin_lock_irqsave (include/linux/spinlock_api_smp.h:132 kernel/locking/spinlock.c:162)
[ 10.406472][ T1] hrtimer_start_range_ns (kernel/time/hrtimer.c:? kernel/time/hrtimer.c:1328)
[ 10.407214][ T1] rpm_suspend (drivers/base/power/runtime.c:632)
[ 10.407794][ T1] rpm_idle (drivers/base/power/runtime.c:562)
[ 10.408341][ T1] __pm_runtime_idle (drivers/base/power/runtime.c:1129)
[ 10.408952][ T1] device_release_driver_internal (drivers/base/dd.c:567)
[ 10.409668][ T1] device_release_driver (drivers/base/dd.c:1331)
[ 10.410252][ T1] bus_remove_device (drivers/base/bus.c:?)
[ 10.410868][ T1] device_del (drivers/base/power/power.h:142 drivers/base/core.c:3879)
[ 10.411397][ T1] serial_base_port_device_remove (drivers/tty/serial/serial_base_bus.c:211)
[ 10.412070][ T1] serial_core_unregister_port (drivers/tty/serial/serial_core.c:3232)
[ 10.412731][ T1] serial_ctrl_unregister_port (drivers/tty/serial/serial_ctrl.c:47)
[ 10.413365][ T1] uart_remove_one_port (drivers/tty/serial/serial_port.c:150)
[ 10.413932][ T1] serial8250_register_8250_port (drivers/tty/serial/8250/8250_core.c:722)
[ 10.414658][ T1] serial8250_probe (drivers/tty/serial/8250/8250_platform.c:195 drivers/tty/serial/8250/8250_platform.c:217)
[ 10.415233][ T1] platform_probe (drivers/base/platform.c:?)
[ 10.415762][ T1] really_probe (drivers/base/dd.c:?)
[ 10.416293][ T1] __driver_probe_device (drivers/base/dd.c:803)
[ 10.416890][ T1] driver_probe_device (drivers/base/dd.c:833)
[ 10.417472][ T1] __device_attach_driver (drivers/base/dd.c:962)
[ 10.418086][ T1] bus_for_each_drv (drivers/base/bus.c:500)
[ 10.418679][ T1] __device_attach (drivers/base/dd.c:1033)
[ 10.419232][ T1] device_initial_probe (drivers/base/dd.c:?)
[ 10.419819][ T1] bus_probe_device (drivers/base/bus.c:576)
[ 10.420374][ T1] device_add (drivers/base/core.c:3696)
[ 10.420888][ T1] platform_device_add (drivers/base/platform.c:757)
[ 10.421475][ T1] platform_device_register (drivers/base/platform.c:820)
[ 10.422094][ T1] hub6_init (drivers/tty/serial/8250/8250_hub6.c:46)
[ 10.422568][ T1] do_one_initcall (init/main.c:1382)
[ 10.423164][ T1] do_initcall_level (init/main.c:1443)
[ 10.423734][ T1] do_initcalls (init/main.c:1457)
[ 10.424247][ T1] do_basic_setup (init/main.c:1480)
[ 10.424778][ T1] kernel_init_freeable (init/main.c:1694)
[ 10.425372][ T1] kernel_init (init/main.c:1584)
[ 10.425879][ T1] ret_from_fork (arch/x86/kernel/process.c:164)
[ 10.426419][ T1] ret_from_fork_asm (arch/x86/entry/entry_32.S:737)
[ 10.427374][ T1] restore_all_switch_stack (arch/x86/entry/entry_32.S:945)
[ 10.427978][ T1]
[ 10.427978][ T1] -> #0 (&dev->power.lock){....}-{3:3}:
[ 10.428776][ T1] __lock_acquire (kernel/locking/lockdep.c:?)
[ 10.429353][ T1] lock_acquire (kernel/locking/lockdep.c:5868)
[ 10.429881][ T1] _raw_spin_lock_irqsave (include/linux/spinlock_api_smp.h:132 kernel/locking/spinlock.c:162)
[ 10.430515][ T1] __pm_runtime_resume (drivers/base/power/runtime.c:?)
[ 10.431200][ T1] __uart_start (drivers/tty/serial/serial_core.c:150)
[ 10.431855][ T1] uart_write (drivers/tty/serial/serial_core.c:634)
[ 10.432366][ T1] n_tty_write (drivers/tty/n_tty.c:557 drivers/tty/n_tty.c:2366)
[ 10.432910][ T1] file_tty_write (drivers/tty/tty_io.c:1006)
[ 10.433445][ T1] redirected_tty_write (drivers/tty/tty_io.c:1126)
[ 10.434006][ T1] do_iter_readv_writev (fs/read_write.c:830)
[ 10.434582][ T1] vfs_writev (fs/read_write.c:1059)
[ 10.435151][ T1] do_writev (fs/read_write.c:1105)
[ 10.435641][ T1] __ia32_sys_writev (fs/read_write.c:1173 fs/read_write.c:1170 fs/read_write.c:1170)
[ 10.436175][ T1] ia32_sys_call (kbuild/obj/consumer/i386-randconfig-054-20260223/./arch/x86/include/generated/asm/syscalls_32.h:170)
[ 10.436701][ T1] __do_fast_syscall_32 (arch/x86/entry/syscall_32.c:?)
[ 10.437261][ T1] do_fast_syscall_32 (arch/x86/entry/syscall_32.c:332)
[ 10.437789][ T1] do_SYSENTER_32 (arch/x86/entry/syscall_32.c:370)
[ 10.438299][ T1] entry_SYSENTER_32 (arch/x86/entry/entry_32.S:836)
[ 10.438877][ T1]
[ 10.438877][ T1] other info that might help us debug this:
[ 10.438877][ T1]
[ 10.439628][ T1] Chain exists of:
[ 10.439628][ T1] &dev->power.lock --> console_owner --> &port_lock_key
[ 10.439628][ T1]
[ 10.440511][ T1] Possible unsafe locking scenario:
[ 10.440511][ T1]
[ 10.441017][ T1] CPU0 CPU1
[ 10.441381][ T1] ---- ----
[ 10.441746][ T1] lock(&port_lock_key);
[ 10.442043][ T1] lock(console_owner);
[ 10.442498][ T1] lock(&port_lock_key);
[ 10.443006][ T1] lock(&dev->power.lock);
[ 10.443320][ T1]
[ 10.443320][ T1] *** DEADLOCK ***
[ 10.443320][ T1]
[ 10.443878][ T1] 5 locks held by systemd/1:
[ 10.444194][ T1] #0: c4177058 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait (drivers/tty/tty_ldisc.c:244)
[ 10.444811][ T1] #1: c41770a0 (&tty->atomic_write_lock){+.+.}-{4:4}, at: file_tty_write (drivers/tty/tty_io.c:939)
[ 10.445450][ T1] #2: c417717c (&tty->termios_rwsem){++++}-{4:4}, at: n_tty_write (drivers/tty/n_tty.c:759 drivers/tty/n_tty.c:2352)
[ 10.446049][ T1] #3: f7c192d8 (&ldata->output_lock){+.+.}-{4:4}, at: n_tty_write (drivers/tty/n_tty.c:515 drivers/tty/n_tty.c:2366)
[ 10.446663][ T1] #4: c2bb2f60 (&port_lock_key){-...}-{3:3}, at: uart_port_ref_lock (include/linux/serial_core.h:717)
The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20260226/202602262005.2ceb43cb-lkp@intel.com
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [thomas-weissschuh:b4/auxclock-nanosleep] aafb55d8d1: WARNING:possible_circular_locking_dependency_detected
2026-02-26 12:42 [thomas-weissschuh:b4/auxclock-nanosleep] aafb55d8d1: WARNING:possible_circular_locking_dependency_detected kernel test robot
@ 2026-02-26 12:46 ` Thomas Weißschuh
2026-02-27 2:11 ` Oliver Sang
0 siblings, 1 reply; 3+ messages in thread
From: Thomas Weißschuh @ 2026-02-26 12:46 UTC (permalink / raw)
To: kernel test robot; +Cc: oe-lkp, lkp
Hi,
On 2026-02-26 20:42:55+0800, kernel test robot wrote:
> again, since we are not sure the purpose of this patch, we make out this report
> again. if low value or you don't need this check, please let us know. thanks
Thanks for the report and sorry for not responding last time.
Indeed, this is only a debugging commit. The warning can be ignored.
Thanks again for the report and LKP in general,
Thomas
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [thomas-weissschuh:b4/auxclock-nanosleep] aafb55d8d1: WARNING:possible_circular_locking_dependency_detected
2026-02-26 12:46 ` Thomas Weißschuh
@ 2026-02-27 2:11 ` Oliver Sang
0 siblings, 0 replies; 3+ messages in thread
From: Oliver Sang @ 2026-02-27 2:11 UTC (permalink / raw)
To: Thomas Weißschuh; +Cc: oe-lkp, lkp, oliver.sang
hi, Thomas,
On Thu, Feb 26, 2026 at 01:46:46PM +0100, Thomas Weißschuh wrote:
> Hi,
>
> On 2026-02-26 20:42:55+0800, kernel test robot wrote:
> > again, since we are not sure the purpose of this patch, we make out this report
> > again. if low value or you don't need this check, please let us know. thanks
>
> Thanks for the report and sorry for not responding last time.
> Indeed, this is only a debugging commit. The warning can be ignored.
got it. thanks a lot for information. we will ignore the test results for this
commit.
>
>
> Thanks again for the report and LKP in general,
> Thomas
^ permalink raw reply [flat|nested] 3+ messages in thread
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2026-02-26 12:42 [thomas-weissschuh:b4/auxclock-nanosleep] aafb55d8d1: WARNING:possible_circular_locking_dependency_detected kernel test robot
2026-02-26 12:46 ` Thomas Weißschuh
2026-02-27 2:11 ` Oliver Sang
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