From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	Hongyan Xu <getshell@seu.edu.cn>,
	Niklas Cassel <cassel@kernel.org>,
	Damien Le Moal <dlemoal@kernel.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 395/456] ata: pata_sl82c105: fix bridge revision use-after-free
Date: Mon, 17 Aug 2026 15:33:05 +0200
Message-ID: <20260817132554.828982340@linuxfoundation.org>
In-Reply-To: <20260817132539.792407575@linuxfoundation.org>
References: <20260817132539.792407575@linuxfoundation.org>
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5.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Hongyan Xu <getshell@seu.edu.cn>

[ Upstream commit 7700a31039cdc6715cb6cce7e7a664ee4e945f67 ]

pci_get_slot() returns a referenced PCI device. Commit 44c10138fd4b
("PCI: Change all drivers to use pci_device->revision") replaced a
configuration-space read with direct access to the cached revision field,
but left that access after pci_dev_put(). The bridge may therefore be freed
before its revision is read.

Read the revision before dropping the reference.

Fixes: 44c10138fd4b ("PCI: Change all drivers to use pci_device->revision")
Signed-off-by: Hongyan Xu <getshell@seu.edu.cn>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/ata/pata_sl82c105.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/ata/pata_sl82c105.c b/drivers/ata/pata_sl82c105.c
index 8487470e2e01e..c32f3b490bb35 100644
--- a/drivers/ata/pata_sl82c105.c
+++ b/drivers/ata/pata_sl82c105.c
@@ -265,6 +265,7 @@ static struct ata_port_operations sl82c105_port_ops = {
 static int sl82c105_bridge_revision(struct pci_dev *pdev)
 {
 	struct pci_dev *bridge;
+	u8 revision;
 
 	/*
 	 * The bridge should be part of the same device, but function 0.
@@ -286,8 +287,9 @@ static int sl82c105_bridge_revision(struct pci_dev *pdev)
 	/*
 	 * We need to find function 0's revision, not function 1
 	 */
+	revision = bridge->revision;
 	pci_dev_put(bridge);
-	return bridge->revision;
+	return revision;
 }
 
 static void sl82c105_fixup(struct pci_dev *pdev)
-- 
2.53.0