linux-kernel - [PATCH AUTOSEL 6.12 163/486] badblocks: Fix a nonsense WARN_ON() which checks whether a u64 variable

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Message-Id: <20250505223922.2682012-163-sashal@kernel.org>
Date: Mon,  5 May 2025 18:33:59 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Coly Li <colyli@...nel.org>,
	Dan Carpenter <dan.carpenter@...aro.org>,
	Yu Kuai <yukuai3@...wei.com>,
	Jens Axboe <axboe@...nel.dk>,
	Sasha Levin <sashal@...nel.org>,
	linux-block@...r.kernel.org
Subject: [PATCH AUTOSEL 6.12 163/486] badblocks: Fix a nonsense WARN_ON() which checks whether a u64 variable < 0

From: Coly Li <colyli@...nel.org>

[ Upstream commit 7e76336e14de9a2b67af96012ddd46c5676cf340 ]

In _badblocks_check(), there are lines of code like this,
1246         sectors -= len;
[snipped]
1251         WARN_ON(sectors < 0);

The WARN_ON() at line 1257 doesn't make sense because sectors is
unsigned long long type and never to be <0.

Fix it by checking directly checking whether sectors is less than len.

Reported-by: Dan Carpenter <dan.carpenter@...aro.org>
Signed-off-by: Coly Li <colyli@...nel.org>
Reviewed-by: Yu Kuai <yukuai3@...wei.com>
Link: https://lore.kernel.org/r/20250309160556.42854-1-colyli@kernel.org
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 block/badblocks.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/block/badblocks.c b/block/badblocks.c
index db4ec8b9b2a8c..a9709771a1015 100644
--- a/block/badblocks.c
+++ b/block/badblocks.c
@@ -1349,14 +1349,15 @@ static int _badblocks_check(struct badblocks *bb, sector_t s, int sectors,
 	len = sectors;
 
 update_sectors:
+	/* This situation should never happen */
+	WARN_ON(sectors < len);
+
 	s += len;
 	sectors -= len;
 
 	if (sectors > 0)
 		goto re_check;
 
-	WARN_ON(sectors < 0);
-
 	if (unacked_badblocks > 0)
 		rv = -1;
 	else if (acked_badblocks > 0)
-- 
2.39.5