Greeting,

FYI, we noticed the following commit (built with gcc-9):

commit: 459b3085f2dd2870cd53bfdafa6591963a5a1f21 ("proc_sysctl: clamp sizes using table->maxlen")
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git Alex-Xu-Hello71/proc_sysctl-clamp-sizes-using-table-maxlen/20210215-225648


in testcase: stress-ng
version: stress-ng-x86_64-0.11-06_20210105
with following parameters:

	nr_threads: 10%
	disk: 1HDD
	testtime: 60s
	fs: ext4
	class: vm
	test: shm-sysv
	cpufreq_governor: performance
	ucode: 0x5003003



on test machine: 96 threads Intel(R) Xeon(R) Gold 6252 CPU @ 2.10GHz with 512G memory

caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):


If you fix the issue, kindly add following tag
Reported-by: kernel test robot <oliver.sang@intel.com>



[    3.591556] AppArmor: AppArmor initialized
[    3.613545] Dentry cache hash table entries: 16777216 (order: 15, 134217728 bytes, vmalloc)
[    3.625219] Inode-cache hash table entries: 8388608 (order: 14, 67108864 bytes, vmalloc)
[    3.626727] Mount-cache hash table entries: 262144 (order: 9, 2097152 bytes, vmalloc)
[    3.627838] Mountpoint-cache hash table entries: 262144 (order: 9, 2097152 bytes, vmalloc)
[    3.629702] sysctl table check failed: vm//stat_refresh cannot read maxlen=0
[    3.630514] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.11.0-rc5-00038-g459b3085f2dd #1
[    3.631513] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0008.031920191559 03/19/2019
[    3.631513] Call Trace:
[    3.631513] dump_stack (kbuild/src/consumer/lib/dump_stack.c:122) 
[    3.631513] __register_sysctl_table (kbuild/src/consumer/fs/proc/proc_sysctl.c:1366) 
[    3.631513] ? register_leaf_sysctl_tables (kbuild/src/consumer/fs/proc/proc_sysctl.c:1457) 
[    3.631513] register_leaf_sysctl_tables (kbuild/src/consumer/fs/proc/proc_sysctl.c:1457) 
[    3.631513] register_leaf_sysctl_tables (kbuild/src/consumer/fs/proc/proc_sysctl.c:1482) 


To reproduce:

        git clone https://github.com/intel/lkp-tests.git
        cd lkp-tests
        bin/lkp install                job.yaml  # job file is attached in this email
        bin/lkp split-job --compatible job.yaml
        bin/lkp run                    compatible-job.yaml



Thanks,
Oliver Sang