On 8/14/25 1:38 PM, kernel test robot wrote:
Hello,
kernel test robot noticed "WARNING:possible_circular_locking_dependency_detected" on:
commit: 555859c514d9b8ca62ca2f1553bf6291ceee1e3a ("[PATCH v2] block: restore default wbt enablement") url: https://github.com/intel-lab-lkp/linux/commits/Julian-Sun/block-restore-defa... base: https://git.kernel.org/cgit/linux/kernel/git/axboe/linux-block.git for-next patch link: https://lore.kernel.org/all/20250812154257.57540-1-sunjunchao@bytedance.com/ patch subject: [PATCH v2] block: restore default wbt enablement
in testcase: boot
config: i386-randconfig-012-20250813 compiler: gcc-12 test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 4G
(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/202508140947.5235b2c7-lkp@intel.com
[ 1.575968][ T1] WARNING: possible circular locking dependency detected [ 1.575968][ T1] 6.17.0-rc1-00012-g555859c514d9 #1 Tainted: G T [ 1.575968][ T1] ------------------------------------------------------ [ 1.575968][ T1] swapper/0/1 is trying to acquire lock: [ 1.575968][ T1] 420f00b4 (cpu_hotplug_lock){++++}-{0:0}, at: static_key_slow_inc (kernel/jump_label.c:191) [ 1.575968][ T1] [ 1.575968][ T1] but task is already holding lock: [ 1.575968][ T1] 46342678 (&q->q_usage_counter(io)#9){++++}-{0:0}, at: blk_mq_freeze_queue_nomemsave (block/blk-mq.c:206) [ 1.575968][ T1] [ 1.575968][ T1] which lock already depends on the new lock. [ 1.575968][ T1] [ 1.575968][ T1] the existing dependency chain (in reverse order) is: [ 1.575968][ T1] [ 1.575968][ T1] -> #2 (&q->q_usage_counter(io)#9){++++}-{0:0}: [ 1.575968][ T1] [ 1.575968][ T1] -> #1 (fs_reclaim){+.+.}-{0:0}: [ 1.575968][ T1] [ 1.575968][ T1] -> #0 (cpu_hotplug_lock){++++}-{0:0}: [ 1.575968][ T1] [ 1.575968][ T1] other info that might help us debug this: [ 1.575968][ T1] [ 1.575968][ T1] Chain exists of: [ 1.575968][ T1] cpu_hotplug_lock --> fs_reclaim --> &q->q_usage_counter(io)#9 [ 1.575968][ T1] [ 1.575968][ T1] Possible unsafe locking scenario: [ 1.575968][ T1] [ 1.575968][ T1] CPU0 CPU1 [ 1.575968][ T1] ---- ---- [ 1.575968][ T1] lock(&q->q_usage_counter(io)#9); [ 1.575968][ T1] lock(fs_reclaim); [ 1.575968][ T1] lock(&q->q_usage_counter(io)#9); [ 1.575968][ T1] rlock(cpu_hotplug_lock); [ 1.575968][ T1] [ 1.575968][ T1] *** DEADLOCK ***
This issue is already being addressed here : https://lore.kernel.org/all/20250814082612.500845-1-nilay@linux.ibm.com/
Thanks, --Nilay