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From:   Haonan Li <lihaonan1105@gmail.com>
To:     Damien Le Moal <dlemoal@kernel.org>,
        Sergey Shtylyov <s.shtylyov@omp.ru>, linux-ide@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     Haonan Li <lihaonan1105@gmail.com>
Subject: Re: [PATCH] pata_lagacy: Handle failed ATA timing computation in opti82c46x_set_piomode
Date:   Wed, 18 Oct 2023 00:52:21 +0000
Message-Id: <20231018005220.2551586-1-lihaonan1105@gmail.com>
In-Reply-To: <1a0c4378-29b2-43b4-982b-0d92dfb8ed4f@kernel.org>
References: <1a0c4378-29b2-43b4-982b-0d92dfb8ed4f@kernel.org>
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The function opti82c46x_set_piomode utilizes the ata_timing_compute()
to determine the appropriate ATA timings for a given device. However,
in certain conditions where the ata_timing_find_mode() function does
not find a valid mode, ata_timing_compute() returns an error (-EINVAL),
leaving the tp struct uninitialized.

This patch checks the return value of ata_timing_compute() and print
err message. This avoids any potential use of uninitialized `tp`
struct in the opti82c46x_set_piomode function.

Signed-off-by: Haonan Li <lihaonan1105@gmail.com>
---
 drivers/ata/pata_legacy.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/ata/pata_legacy.c b/drivers/ata/pata_legacy.c
index 448a511cbc17..3c7163f97aaf 100644
--- a/drivers/ata/pata_legacy.c
+++ b/drivers/ata/pata_legacy.c
@@ -579,12 +579,19 @@ static void opti82c46x_set_piomode(struct ata_port *ap, struct ata_device *adev)
 	clock = 1000000000 / khz[sysclk];
 
 	/* Get the timing data in cycles */
-	ata_timing_compute(adev, adev->pio_mode, &t, clock, 1000);
+	if (ata_timing_compute(adev, adev->pio_mode, &t, clock, 1000)) {
+		dev_err(ap->dev, "adev: unknown mode %d\n", adev->pio_mode);
+		return;
+	}
 
 	/* Setup timing is shared */
 	if (pair) {
 		struct ata_timing tp;
-		ata_timing_compute(pair, pair->pio_mode, &tp, clock, 1000);
+
+		if (ata_timing_compute(pair, pair->pio_mode, &tp, clock, 1000)) {
+			dev_err(ap->dev, "pair: unknown mode %d\n", pair->pio_mode);
+			return;
+		}
 
 		ata_timing_merge(&t, &tp, &t, ATA_TIMING_SETUP);
 	}
-- 
2.34.1