The patch below does not apply to the 5.10-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-5.10.y git checkout FETCH_HEAD git cherry-pick -x fc6bcf9ac4de76f5e7bcd020b3c0a86faff3f2d5 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2026010500-antirust-bacterium-2d22@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From fc6bcf9ac4de76f5e7bcd020b3c0a86faff3f2d5 Mon Sep 17 00:00:00 2001 From: David Hildenbrand david@kernel.org Date: Tue, 21 Oct 2025 12:06:05 +0200 Subject: [PATCH] powerpc/pseries/cmm: call balloon_devinfo_init() also without CONFIG_BALLOON_COMPACTION

Patch series "powerpc/pseries/cmm: two smaller fixes".

Two smaller fixes identified while doing a bigger rework.

This patch (of 2):

We always have to initialize the balloon_dev_info, even when compaction is not configured in: otherwise the containing list and the lock are left uninitialized.

Likely not many such configs exist in practice, but let's CC stable to be sure.

This was found by code inspection.

Link: https://lkml.kernel.org/r/20251021100606.148294-1-david@redhat.com Link: https://lkml.kernel.org/r/20251021100606.148294-2-david@redhat.com Fixes: fe030c9b85e6 ("powerpc/pseries/cmm: Implement balloon compaction") Signed-off-by: David Hildenbrand david@redhat.com Reviewed-by: Ritesh Harjani (IBM) ritesh.list@gmail.com Cc: Christophe Leroy christophe.leroy@csgroup.eu Cc: Madhavan Srinivasan maddy@linux.ibm.com Cc: Michael Ellerman mpe@ellerman.id.au Cc: Nicholas Piggin npiggin@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org

diff --git a/arch/powerpc/platforms/pseries/cmm.c b/arch/powerpc/platforms/pseries/cmm.c index 0823fa2da151..688f5fa1c724 100644 --- a/arch/powerpc/platforms/pseries/cmm.c +++ b/arch/powerpc/platforms/pseries/cmm.c @@ -550,7 +550,6 @@ static int cmm_migratepage(struct balloon_dev_info *b_dev_info,

static void cmm_balloon_compaction_init(void) { - balloon_devinfo_init(&b_dev_info); b_dev_info.migratepage = cmm_migratepage; } #else /* CONFIG_BALLOON_COMPACTION */ @@ -572,6 +571,7 @@ static int cmm_init(void) if (!firmware_has_feature(FW_FEATURE_CMO) && !simulate) return -EOPNOTSUPP;

+ balloon_devinfo_init(&b_dev_info); cmm_balloon_compaction_init();

rc = register_oom_notifier(&cmm_oom_nb);