[PATCH v2 1/6] i2c: xiic: Fix broken locking on tx_msg
From: Marek Vasut <marex@denx.de>
Date: 2021-08-23 21:42:19
Subsystem:
arm/zynq architecture, i2c subsystem, i2c subsystem host drivers, the rest · Maintainers:
Michal Simek, Wolfram Sang, Andi Shyti, Linus Torvalds
The tx_msg is set from multiple places, sometimes without locking, which fall apart on any SMP system. Only ever access tx_msg inside the driver mutex. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Michal Simek <redacted> Cc: Shubhrajyoti Datta <redacted> Cc: Wolfram Sang <wsa@kernel.org> --- V2: Initialize RX message pointer in xiic_start_xfer() too --- drivers/i2c/busses/i2c-xiic.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-)
diff --git a/drivers/i2c/busses/i2c-xiic.c b/drivers/i2c/busses/i2c-xiic.c
index bb93db98404ef..50320dd32eea9 100644
--- a/drivers/i2c/busses/i2c-xiic.c
+++ b/drivers/i2c/busses/i2c-xiic.c@@ -170,7 +170,7 @@ struct xiic_i2c { #define xiic_tx_space(i2c) ((i2c)->tx_msg->len - (i2c)->tx_pos) #define xiic_rx_space(i2c) ((i2c)->rx_msg->len - (i2c)->rx_pos) -static int xiic_start_xfer(struct xiic_i2c *i2c); +static int xiic_start_xfer(struct xiic_i2c *i2c, struct i2c_msg *msgs, int num); static void __xiic_start_xfer(struct xiic_i2c *i2c); /*
@@ -684,15 +684,25 @@ static void __xiic_start_xfer(struct xiic_i2c *i2c) } -static int xiic_start_xfer(struct xiic_i2c *i2c) +static int xiic_start_xfer(struct xiic_i2c *i2c, struct i2c_msg *msgs, int num) { int ret; + mutex_lock(&i2c->lock); + ret = xiic_busy(i2c); + if (ret) + goto out; + + i2c->tx_msg = msgs; + i2c->rx_msg = NULL; + i2c->nmsgs = num; + ret = xiic_reinit(i2c); if (!ret) __xiic_start_xfer(i2c); +out: mutex_unlock(&i2c->lock); return ret;
@@ -710,14 +720,7 @@ static int xiic_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) if (err < 0) return err; - err = xiic_busy(i2c); - if (err) - goto out; - - i2c->tx_msg = msgs; - i2c->nmsgs = num; - - err = xiic_start_xfer(i2c); + err = xiic_start_xfer(i2c, msgs, num); if (err < 0) { dev_err(adap->dev.parent, "Error xiic_start_xfer\n"); goto out;
@@ -725,9 +728,11 @@ static int xiic_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) || (i2c->state == STATE_DONE), HZ)) { + mutex_lock(&i2c->lock); err = (i2c->state == STATE_DONE) ? num : -EIO; goto out; } else { + mutex_lock(&i2c->lock); i2c->tx_msg = NULL; i2c->rx_msg = NULL; i2c->nmsgs = 0;
@@ -735,6 +740,7 @@ static int xiic_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) goto out; } out: + mutex_unlock(&i2c->lock); pm_runtime_mark_last_busy(i2c->dev); pm_runtime_put_autosuspend(i2c->dev); return err;
--
2.32.0