On Thu, Nov 06, 2025 at 02:53:09PM +0800, kernel test robot wrote:
>
>
> Hello,
>
> kernel test robot noticed
> "BUG:Bad_rss-counter_state_mm:#type:MM_ANONPAGES_val:#Comm:kworker##Pid" on:
>
> commit: 25ae03e80acad812e536694c1a07a3f57784ae23 ("[RFC PATCH v7 2/2] mm: Fix
> OOM killer inaccuracy on large many-core systems")
> url:
> https://github.com/intel-lab-lkp/linux/commits/Mathieu-Desnoyers/lib-Introduce-hierarchical-per-cpu-counters/20251031-224455
> base: https://git.kernel.org/cgit/linux/kernel/git/akpm/mm.git mm-everything
> patch link:
> https://lore.kernel.org/all/[email protected]/
> patch subject: [RFC PATCH v7 2/2] mm: Fix OOM killer inaccuracy on large
> many-core systems
>
> in testcase: boot
>
> config: x86_64-randconfig-002-20251103
> compiler: clang-20
> test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G
>
> (please refer to attached dmesg/kmsg for entire log/backtrace)
>
>
> in fact, we observed various BUG:Bad_rss-counter_state_mm issues for this
> commit
> but clean on parent, as below
>
> +------------------------------------------------------------------------+------------+------------+
> | |
> 05880dc4af | 25ae03e80a |
> +------------------------------------------------------------------------+------------+------------+
> | BUG:Bad_rss-counter_state_mm:#type:MM_FILEPAGES_val:#Comm:kworker##Pid | 0
> | 10 |
> | BUG:Bad_rss-counter_state_mm:#type:MM_ANONPAGES_val:#Comm:kworker##Pid | 0
> | 17 |
> | BUG:Bad_rss-counter_state_mm:#type:MM_ANONPAGES_val:#Comm:swapper_Pid | 0
> | 2 |
> | BUG:Bad_rss-counter_state_mm:#type:MM_ANONPAGES_val:#Comm:modprobe_Pid | 0
> | 3 |
> | BUG:Bad_rss-counter_state_mm:#type:MM_FILEPAGES_val:#Comm:modprobe_Pid | 0
> | 1 |
> +------------------------------------------------------------------------+------------+------------+
>
>
> 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 <[email protected]>
> | Closes: https://lore.kernel.org/oe-lkp/[email protected]
>
>
> [ 14.858862][ T67] BUG: Bad rss-counter state mm:ffff8881000655c0
> type:MM_ANONPAGES val:0 Comm:kworker/u9:0 Pid:67
> [ 14.894890][ T69] BUG: Bad rss-counter state mm:ffff888100061cc0
> type:MM_FILEPAGES val:0 Comm:kworker/u9:0 Pid:69
> [ 14.896108][ T69] BUG: Bad rss-counter state mm:ffff888100061cc0
> type:MM_ANONPAGES val:0 Comm:kworker/u9:0 Pid:69
Hmm this shows that percpu_counter_tree_precise_sum() is returning 0 but
percpu_counter_tree_approximate_sum() is off more than
counter->inaccuracy. I have not dig deeper to find why but this needs to
be resolved before considering this series for upstream.
