From: kernel test robot <oliver.sang@intel.com>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: <oe-lkp@lists.linux.dev>, <lkp@intel.com>, <oliver.sang@intel.com>
Subject: [frederic-dynticks:timers/core-v2] [sched/cputime] 241fb10a88: WARNING:possible_recursive_locking_detected
Date: Mon, 26 Jan 2026 22:27:01 +0800 [thread overview]
Message-ID: <202601262235.d81e30e3-lkp@intel.com> (raw)
Hello,
kernel test robot noticed "WARNING:possible_recursive_locking_detected" on:
commit: 241fb10a88a04a5e3170333823d38159e97a5383 ("sched/cputime: Correctly support generic vtime idle time")
https://git.kernel.org/cgit/linux/kernel/git/frederic/linux-dynticks.git timers/core-v2
in testcase: boot
config: x86_64-randconfig-075-20250826
compiler: gcc-14
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/202601262235.d81e30e3-lkp@intel.com
[ 14.567495][ T1] WARNING: possible recursive locking detected
[ 14.567495][ T1] 6.19.0-rc2-00003-g241fb10a88a0 #1 Not tainted
[ 14.567495][ T1] --------------------------------------------
[ 14.567495][ T1] swapper/0/1 is trying to acquire lock:
[ 14.567495][ T1] ffffffff86423ce8 (init_task.vtime_seqcount){....}-{0:0}, at: vtime_account_idle (kernel/sched/cputime.c:767)
[ 14.567495][ T1]
[ 14.567495][ T1] but task is already holding lock:
[ 14.567495][ T1] ffffffff86423ce8 (init_task.vtime_seqcount){....}-{0:0}, at: vtime_task_switch_generic (kernel/sched/cputime.c:776)
[ 14.567495][ T1]
[ 14.567495][ T1] other info that might help us debug this:
[ 14.567495][ T1] Possible unsafe locking scenario:
[ 14.567495][ T1]
[ 14.567495][ T1] CPU0
[ 14.567495][ T1] ----
[ 14.567495][ T1] lock(init_task.vtime_seqcount);
[ 14.567495][ T1]
[ 14.567495][ T1] *** DEADLOCK ***
[ 14.567495][ T1]
[ 14.567495][ T1] May be due to missing lock nesting notation
[ 14.567495][ T1]
[ 14.567495][ T1] 1 lock held by swapper/0/1:
[ 14.567495][ T1] #0: ffffffff86423ce8 (init_task.vtime_seqcount){....}-{0:0}, at: vtime_task_switch_generic (kernel/sched/cputime.c:776)
[ 14.567495][ T1]
[ 14.567495][ T1] stack backtrace:
[ 14.567495][ T1] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.19.0-rc2-00003-g241fb10a88a0 #1 PREEMPT(lazy)
[ 14.567495][ T1] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 14.567495][ T1] Call Trace:
[ 14.567495][ T1] <TASK>
[ 14.567495][ T1] dump_stack_lvl (lib/dump_stack.c:122)
[ 14.567495][ T1] print_deadlock_bug (kernel/locking/lockdep.c:3044)
[ 14.567495][ T1] validate_chain (kernel/locking/lockdep.c:3897)
[ 14.567495][ T1] __lock_acquire (kernel/locking/lockdep.c:5237 (discriminator 1))
[ 14.567495][ T1] ? vtime_account_idle (kernel/sched/cputime.c:767)
[ 14.567495][ T1] lock_acquire (include/trace/events/lock.h:24 (discriminator 1) kernel/locking/lockdep.c:5831 (discriminator 1))
[ 14.567495][ T1] ? vtime_account_idle (kernel/sched/cputime.c:767)
[ 14.567495][ T1] ? lock_acquire (include/trace/events/lock.h:24 (discriminator 2) kernel/locking/lockdep.c:5831 (discriminator 2))
[ 14.567495][ T1] do_write_seqcount_begin (include/linux/seqlock.h:431 include/linux/seqlock.h:478 include/linux/seqlock.h:503)
[ 14.567495][ T1] ? vtime_account_idle (kernel/sched/cputime.c:767)
[ 14.567495][ T1] vtime_account_idle (kernel/sched/cputime.c:767)
[ 14.567495][ T1] vtime_task_switch_generic (kernel/sched/cputime.c:777)
[ 14.567495][ T1] finish_task_switch+0x11e/0x4a0
[ 14.567495][ T1] ? rest_init (init/main.c:1570)
[ 14.567495][ T1] schedule_tail (kernel/sched/core.c:5185)
[ 14.567495][ T1] ? rest_init (init/main.c:1570)
[ 14.567495][ T1] ret_from_fork (arch/x86/kernel/process.c:157 (discriminator 1))
[ 14.567495][ T1] ? arch_exit_to_user_mode_prepare+0xe0/0xe0
[ 14.567495][ T1] ? __switch_to (arch/x86/include/asm/bitops.h:202 (discriminator 1) arch/x86/include/asm/bitops.h:232 (discriminator 1) include/asm-generic/bitops/instrumented-non-atomic.h:142 (discriminator 1) include/linux/thread_info.h:131 (discriminator 1) include/linux/sched.h:2018 (discriminator 1) arch/x86/include/asm/fpu/sched.h:34 (discriminator 1) arch/x86/kernel/process_64.c:619 (discriminator 1))
[ 14.567495][ T1] ? rest_init (init/main.c:1570)
[ 14.567495][ T1] ret_from_fork_asm (arch/x86/entry/entry_64.S:256)
[ 14.567495][ T1] </TASK>
The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20260126/202601262235.d81e30e3-lkp@intel.com
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
reply other threads:[~2026-01-26 14:27 UTC|newest]
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