linux-kernel - [linus:master] [sched] 8671bad873: INFO:task_blocked_for_more

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Message-ID: <202509051010.e06823ab-lkp@intel.com>
Date: Fri, 5 Sep 2025 10:49:35 +0800
From: kernel test robot <oliver.sang@...el.com>
To: "Luis Claudio R. Goncalves" <lgoncalv@...hat.com>
CC: <oe-lkp@...ts.linux.dev>, <lkp@...el.com>, <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <peterz@...radead.org>, Crystal Wood <crwood@...hat.com>,
	Wander Lairson Costa <wander@...hat.com>, Valentin Schneider
	<vschneid@...hat.com>, Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
	<aubrey.li@...ux.intel.com>, <yu.c.chen@...el.com>, <oliver.sang@...el.com>
Subject: [linus:master] [sched]  8671bad873:
 INFO:task_blocked_for_more_than#seconds



Hello,

kernel test robot noticed "INFO:task_blocked_for_more_than#seconds" on:

commit: 8671bad873ebeb082afcf7b4501395c374da6023 ("sched: Do not call __put_task_struct() on rt if pi_blocked_on is set")
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master

[test failed on      linus/master 08b06c30a44555a8b1d14950e4462a52bfa0758b]
[test failed on linux-next/master 5d50cf9f7cf20a17ac469c20a2e07c29c1f6aab7]

in testcase: rcutorture
version: 
with following parameters:

	runtime: 300s
	test: cpuhotplug
	torture_type: tasks-rude



config: i386-randconfig-017-20250830
compiler: gcc-12
test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G

(please refer to attached dmesg/kmsg for entire log/backtrace)


the issue happens randomly and we observed various issues in tests by this
commit, while parent keeps clean.

=========================================================================================
tbox_group/testcase/rootfs/kconfig/compiler/runtime/test/torture_type:
  vm-snb/rcutorture/debian-11.1-i386-20220923.cgz/i386-randconfig-017-20250830/gcc-12/300s/cpuhotplug/tasks-rude

7de9d4f946383f48 8671bad873ebeb082afcf7b4501
---------------- ---------------------------
       fail:runs  %reproduction    fail:runs
           |             |             |
           :200         16%          32:200   dmesg.BUG:kernel_hang_in_boot_stage
           :200          0%           1:200   dmesg.BUG:soft_lockup-CPU##stuck_for#s![swapper:#]
           :200          1%           2:200   dmesg.BUG:workqueue_lockup-pool
           :200          0%           1:200   dmesg.EIP:kthread_affine_preferred
           :200          0%           1:200   dmesg.EIP:lock_release
           :200          0%           1:200   dmesg.EIP:tick_clock_notify
           :200         12%          23:200   dmesg.INFO:task_blocked_for_more_than#seconds
           :200         12%          23:200   dmesg.Kernel_panic-not_syncing:hung_task:blocked_tasks
           :200          0%           1:200   dmesg.Kernel_panic-not_syncing:softlockup:hung_tasks
           :200          0%           1:200   dmesg.WARNING:at_kernel/kthread.c:#kthread_affine_preferred



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@...el.com>
| Closes: https://lore.kernel.org/oe-lkp/202509051010.e06823ab-lkp@intel.com


[  994.935251][   T26] INFO: task swapper/0:1 blocked for more than 491 seconds.
[  994.947414][   T26]       Not tainted 6.16.0-rc6-00086-g8671bad873eb #1
[  994.951523][   T26] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[  994.960576][   T26] task:swapper/0       state:D stack:5016  pid:1     tgid:1     ppid:0      task_flags:0x0140 flags:0x00004000
[  994.972581][   T26] Call Trace:
[ 994.998429][ T26] __schedule (kernel/sched/core.c:5354 kernel/sched/core.c:6954) 
[ 995.035758][ T26] schedule (kernel/sched/core.c:7037 kernel/sched/core.c:7051) 
[ 995.044863][ T26] async_synchronize_cookie_domain (kernel/async.c:317 kernel/async.c:310) 
[ 995.050698][ T26] ? do_wait_intr (kernel/sched/wait.c:384) 
[ 995.059798][ T26] wait_for_initramfs (init/initramfs.c:778) 
[ 995.067798][ T26] populate_rootfs (init/initramfs.c:789) 
[ 995.070767][ T26] do_one_initcall (init/main.c:1274) 
[ 995.074441][ T26] ? initramfs_async_setup (init/initramfs.c:782) 
[ 995.098384][ T26] do_initcalls (init/main.c:1335 init/main.c:1352) 
[ 995.136744][ T26] kernel_init_freeable (init/main.c:1588) 
[ 995.136744][ T26] ? rest_init (init/main.c:1466) 
[ 995.158663][ T26] kernel_init (init/main.c:1476) 
[ 995.177750][ T26] ret_from_fork (arch/x86/kernel/process.c:154) 
[ 995.178146][ T26] ? rest_init (init/main.c:1466) 
[ 995.230129][ T26] ret_from_fork_asm (arch/x86/entry/entry_32.S:737) 
[ 995.230129][ T26] entry_INT80_32 (arch/x86/entry/entry_32.S:945) 
[  995.268743][   T26]
[  995.268743][   T26] Showing all locks held in the system:
[  995.336987][   T26] 1 lock held by khungtaskd/26:
[ 995.446697][ T26] #0: 830cce10 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks (kernel/locking/lockdep.c:6768 (discriminator 1)) 
[  995.464546][   T26] 4 locks held by kworker/u4:2/29:
[  995.470758][   T26] 2 locks held by kworker/0:3/38:
[  995.498593][   T26]
[  995.599251][   T26] =============================================
[  995.599251][   T26]
[  995.729940][   T26] Kernel panic - not syncing: hung_task: blocked tasks
[  995.729940][   T26] CPU: 0 UID: 0 PID: 26 Comm: khungtaskd Not tainted 6.16.0-rc6-00086-g8671bad873eb #1 PREEMPT(full)
[  995.729940][   T26] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[  995.729940][   T26] Call Trace:
[ 995.729940][ T26] dump_stack_lvl (lib/dump_stack.c:124) 
[ 995.729940][ T26] dump_stack (lib/dump_stack.c:130) 
[ 995.729940][ T26] panic (kernel/panic.c:382) 
[ 995.729940][ T26] check_hung_uninterruptible_tasks (kernel/hung_task.c:311) 
[ 995.729940][ T26] watchdog (kernel/hung_task.c:470) 
[ 995.729940][ T26] kthread (kernel/kthread.c:464) 
[ 995.729940][ T26] ? check_hung_uninterruptible_tasks (kernel/hung_task.c:453) 
[ 995.729940][ T26] ? kthread_complete_and_exit (kernel/kthread.c:413) 
[ 995.729940][ T26] ret_from_fork (arch/x86/kernel/process.c:154) 
[ 995.729940][ T26] ? kthread_complete_and_exit (kernel/kthread.c:413) 
[ 995.729940][ T26] ret_from_fork_asm (arch/x86/entry/entry_32.S:737) 
[ 995.729940][ T26] entry_INT80_32 (arch/x86/entry/entry_32.S:945) 



The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20250905/202509051010.e06823ab-lkp@intel.com



-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki