This is a note to let you know that I've just added the patch titled
i2c: rk3x: fix potential spinlock recursion on poll
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
i2c-rk3x-fix-potential-spinlock-recursion-on-poll.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 2ca91f74fb80f06fd0807e03fdd125e5e60a9eda
Author: Jensen Huang <jensenhuang@xxxxxxxxxxxxxxx>
Date: Thu Dec 7 16:21:59 2023 +0800
i2c: rk3x: fix potential spinlock recursion on poll
[ 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@xxxxxxxxxxxxxxx>
Reviewed-by: Heiko Stuebner <heiko@xxxxxxxxx>
Reviewed-by: Andi Shyti <andi.shyti@xxxxxxxxxx>
Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
index b31cf4f18f85..6aa4f1f06240 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);
@@ -1310,6 +1317,8 @@ 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) {
