The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 694d6b99923eb05a8fd188be44e26077d19f0e21 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025072811-ethanol-arbitrary-a664@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 694d6b99923eb05a8fd188be44e26077d19f0e21 Mon Sep 17 00:00:00 2001 From: Harry Yoo harry.yoo@oracle.com Date: Fri, 4 Jul 2025 19:30:53 +0900 Subject: [PATCH] mm/zsmalloc: do not pass __GFP_MOVABLE if CONFIG_COMPACTION=n
Commit 48b4800a1c6a ("zsmalloc: page migration support") added support for migrating zsmalloc pages using the movable_operations migration framework. However, the commit did not take into account that zsmalloc supports migration only when CONFIG_COMPACTION is enabled. Tracing shows that zsmalloc was still passing the __GFP_MOVABLE flag even when compaction is not supported.
This can result in unmovable pages being allocated from movable page blocks (even without stealing page blocks), ZONE_MOVABLE and CMA area.
Possible user visible effects: - Some ZONE_MOVABLE memory can be not actually movable - CMA allocation can fail because of this - Increased memory fragmentation due to ignoring the page mobility grouping feature I'm not really sure who uses kernels without compaction support, though :(
To fix this, clear the __GFP_MOVABLE flag when !IS_ENABLED(CONFIG_COMPACTION).
Link: https://lkml.kernel.org/r/20250704103053.6913-1-harry.yoo@oracle.com Fixes: 48b4800a1c6a ("zsmalloc: page migration support") Signed-off-by: Harry Yoo harry.yoo@oracle.com Acked-by: David Hildenbrand david@redhat.com Reviewed-by: Sergey Senozhatsky senozhatsky@chromium.org Cc: Minchan Kim minchan@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index 999b513c7fdf..f3e2215f95eb 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -1043,6 +1043,9 @@ static struct zspage *alloc_zspage(struct zs_pool *pool, if (!zspage) return NULL;
+ if (!IS_ENABLED(CONFIG_COMPACTION)) + gfp &= ~__GFP_MOVABLE; + zspage->magic = ZSPAGE_MAGIC; zspage->pool = pool; zspage->class = class->index;