[Bug 220765] New: Memory leak in maple_node (Maple Tree) on Linux 6.18-rc4

[Andrew Morton]

(switched to email.  Please respond via emailed reply-to-all, not via the
bugzilla web interface).

On Fri, 07 Nov 2025 15:41:52 +0000 bugzilla-daemon at kernel.org wrote:

> https://bugzilla.kernel.org/show_bug.cgi?id=220765
> 
>             Bug ID: 220765
>            Summary: Memory leak in maple_node (Maple Tree) on Linux
>                     6.18-rc4
>            Product: Memory Management
>            Version: 2.5
>           Hardware: AMD
>                 OS: Linux
>             Status: NEW
>           Severity: high
>           Priority: P3
>          Component: Slab Allocator
>           Assignee: akpm at linux-foundation.org
>           Reporter: tytanick at gmail.com
>         Regression: No
> 
> Created attachment 308920
>   --> https://bugzilla.kernel.org/attachment.cgi?id=308920&action=edit
> htop
> 
> Been using 6.18 kernel and i have noticed that there is some memory leak.
> Currently mapple_node takes 86GB when server does not do much.
> I do not see that issue on 6.17 kernel

Thanks.   Cc's added.

In the future, please report kernel issues via email - we don't use
bugzilla.

Running

	scripts/get_maintainer.pl lib/maple_tree.c

is the way to find out who to email.

> Total 1000 GB memory
> ASRockRack GENOA2D24G-2L
> 2x AMD EPYC 9654 96-Core Processor
> Running Proxmox 9
> 
> 
>  Active / Total Objects (% used)    : 472110239 / 472257124 (100.0%)
>  Active / Total Slabs (% used)      : 7385489 / 7385489 (100.0%)
>  Active / Total Caches (% used)     : 164 / 231 (71.0%)
>  Active / Total Size (% used)       : 95486861.00K / 95528053.72K (100.0%)
>  Minimum / Average / Maximum Object : 0.01K / 0.20K / 8.06K
> 
>   OBJS ACTIVE  USE OBJ SIZE  SLABS OBJ/SLAB CACHE SIZE NAME
> 345907216 345897683  99%    0.25K 5404801       64  86476816K maple_node
> 120873408 120841337  99%    0.06K 1888647       64   7554588K dmaengine-unmap-2
> 224256 223324  99%    0.01K    438      512      1752K kmalloc-8
> 224040 224040 100%    0.13K   3734       60     29872K kernfs_node_cache
> 196608 196608 100%    0.01K    384      512      1536K kmalloc-cg-8
> 196160 166455  84%    0.50K   3065       64     98080K kmalloc-512
> 
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