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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Billy Tsai <billy_tsai@aspeedtech.com>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>,
	Sasha Levin <sashal@kernel.org>,
	linux-i3c@lists.infradead.org
Subject: [PATCH AUTOSEL 6.1 6/6] i3c: master: mipi-i3c-hci: Fix a kernel panic for accessing DAT_data.
Date: Sun, 12 Nov 2023 08:24:01 -0500	[thread overview]
Message-ID: <20231112132408.174499-6-sashal@kernel.org> (raw)
In-Reply-To: <20231112132408.174499-1-sashal@kernel.org>

From: Billy Tsai <billy_tsai@aspeedtech.com>

[ Upstream commit b53e9758a31c683fc8615df930262192ed5f034b ]

The `i3c_master_bus_init` function may attach the I2C devices before the
I3C bus initialization. In this flow, the DAT `alloc_entry`` will be used
before the DAT `init`. Additionally, if the `i3c_master_bus_init` fails,
the DAT `cleanup` will execute before the device is detached, which will
execue DAT `free_entry` function. The above scenario can cause the driver
to use DAT_data when it is NULL.

Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com>
Link: https://lore.kernel.org/r/20231023080237.560936-1-billy_tsai@aspeedtech.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/i3c/master/mipi-i3c-hci/dat_v1.c | 29 ++++++++++++++++--------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
index 97bb49ff5b53b..47b9b4d4ed3fc 100644
--- a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
+++ b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
@@ -64,15 +64,17 @@ static int hci_dat_v1_init(struct i3c_hci *hci)
 		return -EOPNOTSUPP;
 	}
 
-	/* use a bitmap for faster free slot search */
-	hci->DAT_data = bitmap_zalloc(hci->DAT_entries, GFP_KERNEL);
-	if (!hci->DAT_data)
-		return -ENOMEM;
-
-	/* clear them */
-	for (dat_idx = 0; dat_idx < hci->DAT_entries; dat_idx++) {
-		dat_w0_write(dat_idx, 0);
-		dat_w1_write(dat_idx, 0);
+	if (!hci->DAT_data) {
+		/* use a bitmap for faster free slot search */
+		hci->DAT_data = bitmap_zalloc(hci->DAT_entries, GFP_KERNEL);
+		if (!hci->DAT_data)
+			return -ENOMEM;
+
+		/* clear them */
+		for (dat_idx = 0; dat_idx < hci->DAT_entries; dat_idx++) {
+			dat_w0_write(dat_idx, 0);
+			dat_w1_write(dat_idx, 0);
+		}
 	}
 
 	return 0;
@@ -87,7 +89,13 @@ static void hci_dat_v1_cleanup(struct i3c_hci *hci)
 static int hci_dat_v1_alloc_entry(struct i3c_hci *hci)
 {
 	unsigned int dat_idx;
+	int ret;
 
+	if (!hci->DAT_data) {
+		ret = hci_dat_v1_init(hci);
+		if (ret)
+			return ret;
+	}
 	dat_idx = find_first_zero_bit(hci->DAT_data, hci->DAT_entries);
 	if (dat_idx >= hci->DAT_entries)
 		return -ENOENT;
@@ -103,7 +111,8 @@ static void hci_dat_v1_free_entry(struct i3c_hci *hci, unsigned int dat_idx)
 {
 	dat_w0_write(dat_idx, 0);
 	dat_w1_write(dat_idx, 0);
-	__clear_bit(dat_idx, hci->DAT_data);
+	if (hci->DAT_data)
+		__clear_bit(dat_idx, hci->DAT_data);
 }
 
 static void hci_dat_v1_set_dynamic_addr(struct i3c_hci *hci,
-- 
2.42.0


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      reply	other threads:[~2023-11-13  9:14 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-12 13:23 [PATCH AUTOSEL 6.1 1/6] i3c: mipi-i3c-hci: Fix out of bounds access in hci_dma_irq_handler Sasha Levin
2023-11-12 13:24 ` Sasha Levin [this message]

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