powerpc/pseries/cmm: call balloon_devinfo_init() also without CONFIG_BALLOON_COMPACTION

commit fc6bcf9ac4de76f5e7bcd020b3c0a86faff3f2d5 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/powerpc/platforms/pseries/cmm.c b/arch/powerpc/platforms/pseries/cmm.c
index 5f4037c1d7fe80941f4ebcb4cf3e736f7699c7f1..1065f08cdcb90d200d4d8bde7d8ff37bfc52ad64 100644 (file)
--- 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);