[PATCH 3/3] can: rcar_canfd: Fix interrupt registration order

[Biju]

From: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>

In rcar_canfd_probe(), global interrupts are requested via
devm_request_irq() before rcar_canfd_global_init() enables the clocks
and before the per-channel structures in gpriv->ch[] are allocated.

If the interrupt is shared and fires immediately, the handler
rcar_canfd_global_err_interrupt() will invoke
rcar_canfd_handle_global_err(), leading to a NULL pointer
dereference.

Move the rcar_canfd_global_init() and per-channel probe calls ahead
of the devm_request_irq() calls so that clocks are enabled and
gpriv->ch[] is fully populated before any global interrupt can be
delivered. The IRQ failure paths now jump to fail_channel instead of
fail_dev, since channels are allocated earlier and must be torn down
on this path too.

Fixes: dd3bd23eb438 ("can: rcar_canfd: Add Renesas R-Car CAN FD driver")
Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
---
 drivers/net/can/rcar/rcar_canfd.c | 30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
index e88554388553..4ee108abffb8 100644
--- a/drivers/net/can/rcar/rcar_canfd.c
+++ b/drivers/net/can/rcar/rcar_canfd.c
@@ -2216,6 +2216,17 @@ static int rcar_canfd_probe(struct platform_device *pdev)
 	gpriv->base = addr;
 	gpriv->fcbase = addr + gpriv->info->regs->coffset;
 
+	err = rcar_canfd_global_init(gpriv);
+	if (err)
+		goto fail_dev;
+
+	for_each_set_bit(ch, &gpriv->channels_mask, info->max_channels) {
+		err = rcar_canfd_channel_probe(gpriv, ch, fcan_freq,
+					       transceivers[ch]);
+		if (err)
+			goto fail_channel;
+	}
+
 	/* Request IRQ that's common for both channels */
 	if (info->shared_global_irqs) {
 		err = devm_request_irq(dev, ch_irq,
@@ -2224,7 +2235,7 @@ static int rcar_canfd_probe(struct platform_device *pdev)
 		if (err) {
 			dev_err(dev, "devm_request_irq %d failed: %pe\n",
 				ch_irq, ERR_PTR(err));
-			goto fail_dev;
+			goto fail_channel;
 		}
 
 		err = devm_request_irq(dev, g_irq, rcar_canfd_global_interrupt,
@@ -2232,7 +2243,7 @@ static int rcar_canfd_probe(struct platform_device *pdev)
 		if (err) {
 			dev_err(dev, "devm_request_irq %d failed: %pe\n",
 				g_irq, ERR_PTR(err));
-			goto fail_dev;
+			goto fail_channel;
 		}
 	} else {
 		err = devm_request_irq(dev, g_recc_irq,
@@ -2242,7 +2253,7 @@ static int rcar_canfd_probe(struct platform_device *pdev)
 		if (err) {
 			dev_err(dev, "devm_request_irq %d failed: %pe\n",
 				g_recc_irq, ERR_PTR(err));
-			goto fail_dev;
+			goto fail_channel;
 		}
 
 		err = devm_request_irq(dev, g_err_irq,
@@ -2251,19 +2262,8 @@ static int rcar_canfd_probe(struct platform_device *pdev)
 		if (err) {
 			dev_err(dev, "devm_request_irq %d failed: %pe\n",
 				g_err_irq, ERR_PTR(err));
-			goto fail_dev;
-		}
-	}
-
-	err = rcar_canfd_global_init(gpriv);
-	if (err)
-		goto fail_dev;
-
-	for_each_set_bit(ch, &gpriv->channels_mask, info->max_channels) {
-		err = rcar_canfd_channel_probe(gpriv, ch, fcan_freq,
-					       transceivers[ch]);
-		if (err)
 			goto fail_channel;
+		}
 	}
 
 	platform_set_drvdata(pdev, gpriv);
-- 
2.43.0