Re: [RFC PATCH v3 6/7] slub: Delay freezing of partial slabs

[Chengming Zhou]

On 2023/10/26 13:49, kernel test robot wrote:
> 
> 
> Hello,
> 
> kernel test robot noticed "WARNING:at_mm/slub.c:#___slab_alloc" on:
> 
> commit: b34342e2732b0dc92b29d6807c5314e2e5e0c27c ("[RFC PATCH v3 6/7] slub: Delay freezing of partial slabs")
> url: https://github.com/intel-lab-lkp/linux/commits/chengming-zhou-linux-dev/slub-Keep-track-of-whether-slub-is-on-the-per-node-partial-list/20231024-173519
> base: git://git.kernel.org/cgit/linux/kernel/git/vbabka/slab.git for-next
> patch link: https://lore.kernel.org/all/20231024093345.3676493-7-chengming.zhou@xxxxxxxxx/
> patch subject: [RFC PATCH v3 6/7] slub: Delay freezing of partial slabs
> 
> in testcase: rcutorture
> version: 
> with following parameters:
> 
> 	runtime: 300s
> 	test: default
> 	torture_type: rcu
> 
> 
> 
> 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)
> 
> 
> +------------------------------------------------+------------+------------+
> |                                                | e87d1d9973 | b34342e273 |
> +------------------------------------------------+------------+------------+
> | boot_successes                                 | 15         | 0          |
> | boot_failures                                  | 0          | 15         |
> | WARNING:at_mm/slub.c:#___slab_alloc            | 0          | 15         |
> | RIP:___slab_alloc                              | 0          | 15         |
> +------------------------------------------------+------------+------------+
> 
> 
> 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@xxxxxxxxx>
> | Closes: https://lore.kernel.org/oe-lkp/202310261032.b4590eb0-oliver.sang@xxxxxxxxx
> 
> 
> [    4.907500][    T1] ------------[ cut here ]------------
> [ 4.908232][ T1] WARNING: CPU: 0 PID: 1 at mm/slub.c:577 ___slab_alloc (mm/slub.c:577 mm/slub.c:3033 mm/slub.c:3205) 
> [    4.909242][    T1] Modules linked in:
> [    4.909739][    T1] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.6.0-rc5-00013-gb34342e2732b #1
> [ 4.910746][ T1] RIP: 0010:___slab_alloc (mm/slub.c:577 mm/slub.c:3033 mm/slub.c:3205) 

The warning is triggered by "lockdep_assert_irqs_disabled()" in __slab_update_freelist(),
which is called in the new introduced freeze_slab().

We should fix it by using "slab_update_freelist()" in freeze_slab() instead, which will
disable the interrupts correctly.

Thanks!