linux-kernel - [PATCH][V2][next] dm space maps: Fix uninitialized variable r2

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Message-Id: <20210521095101.42737-1-colin.king@canonical.com>
Date:   Fri, 21 May 2021 10:51:01 +0100
From:   Colin King <colin.king@...onical.com>
To:     Alasdair Kergon <agk@...hat.com>,
        Mike Snitzer <snitzer@...hat.com>, dm-devel@...hat.com,
        Joe Thornber <ejt@...hat.com>
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH][V2][next] dm space maps: Fix uninitialized variable r2

From: Colin Ian King <colin.king@...onical.com>

In the case where recursing(mm) is true variable r2 is not
inintialized and an uninitialized value is being used in the
call combine_errors later on. Fix this by setting r2 to zero.

Addresses-Coverity: ("Uninitialized scalar variable")
Fixes: def6a7a9a7f0 ("dm space maps: improve performance with inc/dec on ranges of blocks")
Signed-off-by: Colin Ian King <colin.king@...onical.com>
---

V2: Add fix in function sm_metadata_inc_blocks

---
 drivers/md/persistent-data/dm-space-map-metadata.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/md/persistent-data/dm-space-map-metadata.c b/drivers/md/persistent-data/dm-space-map-metadata.c
index 3b70ee861cf5..a9a362777fad 100644
--- a/drivers/md/persistent-data/dm-space-map-metadata.c
+++ b/drivers/md/persistent-data/dm-space-map-metadata.c
@@ -417,6 +417,7 @@ static int sm_metadata_inc_blocks(struct dm_space_map *sm, dm_block_t b, dm_bloc
 		r = add_bop(smm, BOP_INC, b, e);
 		if (r)
 			return r;
+		r2 = 0;
 	} else {
 		in(smm);
 		r = sm_ll_inc(&smm->ll, b, e, &nr_allocations);
@@ -432,9 +433,10 @@ static int sm_metadata_dec_blocks(struct dm_space_map *sm, dm_block_t b, dm_bloc
 	int32_t nr_allocations;
 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 
-	if (recursing(smm))
+	if (recursing(smm)) {
 		r = add_bop(smm, BOP_DEC, b, e);
-	else {
+		r2 = 0;
+	} else {
 		in(smm);
 		r = sm_ll_dec(&smm->ll, b, e, &nr_allocations);
 		r2 = out(smm);
-- 
2.31.1