[PATCH AUTOSEL 5.10 8/9] i2c: rk3x: fix potential spinlock recursion on poll

Sasha Levin
2023-12-26T00:26:02Z

From: Jensen Huang <jensenhuang@friendlyarm.com>

[ Upstream commit 19cde9c92b8d3b7ee555d0da3bcb0232d3a784f4 ]

Possible deadlock scenario (on reboot):
rk3x_i2c_xfer_common(polling)
-> rk3x_i2c_wait_xfer_poll()
-> rk3x_i2c_irq(0, i2c);
--> spin_lock(&i2c->lock);
...
<rk3x i2c interrupt>
-> rk3x_i2c_irq(0, i2c);
--> spin_lock(&i2c->lock); (deadlock here)

Store the IRQ number and disable/enable it around the polling transfer.
This patch has been tested on NanoPC-T4.

Signed-off-by: Jensen Huang <jensenhuang@friendlyarm.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/i2c/busses/i2c-rk3x.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
index 13c14eb175e94..6abcf975a2db9 100644
--- a/drivers/i2c/busses/i2c-rk3x.c
+++ b/drivers/i2c/busses/i2c-rk3x.c
@@ -178,6 +178,7 @@ struct rk3x_i2c_soc_data {
* @clk: function clk for rk3399 or function & Bus clks for others
* @pclk: Bus clk for rk3399
* @clk_rate_nb: i2c clk rate change notify
+ * @irq: irq number
* @t: I2C known timing information
* @lock: spinlock for the i2c bus
* @wait: the waitqueue to wait for i2c transfer
@@ -200,6 +201,7 @@ struct rk3x_i2c {
struct clk *clk;
struct clk *pclk;
struct notifier_block clk_rate_nb;
+ int irq;

/* Settings */
struct i2c_timings t;
@@ -1087,13 +1089,18 @@ static int rk3x_i2c_xfer_common(struct i2c_adapter *adap,

spin_unlock_irqrestore(&i2c->lock, flags);

- rk3x_i2c_start(i2c);
-
if (!polling) {
+ rk3x_i2c_start(i2c);
+
timeout = wait_event_timeout(i2c->wait, !i2c->busy,
msecs_to_jiffies(WAIT_TIMEOUT));
} else {
+ disable_irq(i2c->irq);
+ rk3x_i2c_start(i2c);
+
timeout = rk3x_i2c_wait_xfer_poll(i2c);
+
+ enable_irq(i2c->irq);
}

spin_lock_irqsave(&i2c->lock, flags);
@@ -1301,6 +1308,8 @@ static int rk3x_i2c_probe(struct platform_device *pdev)
return ret;
}

+ i2c->irq = irq;
+
platform_set_drvdata(pdev, i2c);

if (i2c->soc_data->calc_timings == rk3x_i2c_v0_calc_timings) {
--
2.43.0

_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org