[PATCH] bcachefs: zero-init move_bucket struct in bch2_copygc_get_buckets()

[Gianfranco Trad]

zero-init move_bucket struct b fields in bch2_copygc_get_buckets() 
to mitigate later uninit-value-use KMSAN reported bug.

Reported-by: syzbot+8689d10f1894eedf774d@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?extid=8689d10f1894eedf774d
Tested-by: syzbot+8689d10f1894eedf774d@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Gianfranco Trad <gianf.trad@xxxxxxxxx>
---
 fs/bcachefs/movinggc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/bcachefs/movinggc.c b/fs/bcachefs/movinggc.c
index d658be90f737..cdc456b03bec 100644
--- a/fs/bcachefs/movinggc.c
+++ b/fs/bcachefs/movinggc.c
@@ -171,7 +171,8 @@ static int bch2_copygc_get_buckets(struct moving_context *ctxt,
 				  lru_pos(BCH_LRU_FRAGMENTATION_START, 0, 0),
 				  lru_pos(BCH_LRU_FRAGMENTATION_START, U64_MAX, LRU_TIME_MAX),
 				  0, k, ({
-		struct move_bucket b = { .k.bucket = u64_to_bucket(k.k->p.offset) };
+		struct move_bucket b = { 0 };
+		b.k.bucket = u64_to_bucket(k.k->p.offset);
 		int ret2 = 0;
 
 		saw++;
-- 
2.43.0