[PATCH v2 4/4] mfd: tps65217: Fix NULL pointer dereference in remove callback

["Жамбакиев Радий Рикардинович" <r.zhambakiev@prosoftsystems.ru>]

When the device is probed without an interrupt, tps65217_irq_init() is
never called and tps->irq_domain remains NULL. The remove callback
still looks up IRQ mappings and calls irq_domain_remove(), which
dereferences the NULL domain and crashes the kernel. The mapping
lookup with a NULL domain falls back to the default IRQ domain and can
dispose mappings belonging to other devices.

Quiesce the parent interrupt before tearing down the domain: the
devres-managed interrupt is only freed after the remove callback
returns, so an interrupt firing in that window would run the threaded
handler with a NULL irq_domain. Also call disable_irq_wake() to balance
the enable_irq_wake() done in tps65217_irq_init().

Fixes: 6556bdacf646fcaa ("mfd: tps65217: Add support for IRQs")
Cc: stable@vger.kernel.org
Signed-off-by: Radiy Zhambakiev <r.zhambakiev@prosoftsystems.ru>
---
 drivers/mfd/tps65217.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/drivers/mfd/tps65217.c b/drivers/mfd/tps65217.c
index d535d140c2e9..9f4afbaa6524 100644
--- a/drivers/mfd/tps65217.c
+++ b/drivers/mfd/tps65217.c
@@ -403,17 +403,20 @@ static int tps65217_probe(struct i2c_client *client)
 static void tps65217_remove(struct i2c_client *client)
 {
 	struct tps65217 *tps = i2c_get_clientdata(client);
-	unsigned int virq;
-	int i;
 
-	for (i = 0; i < TPS65217_NUM_IRQ; i++) {
-		virq = irq_find_mapping(tps->irq_domain, i);
-		if (virq)
-			irq_dispose_mapping(virq);
-	}
+	if (!tps->irq_domain)
+		return;
 
-	irq_domain_remove(tps->irq_domain);
-	tps->irq_domain = NULL;
+	/*
+	 * The interrupt is only freed by devres after this callback
+	 * returns, so make sure no handler can run while the domain
+	 * is being torn down.
+	 */
+	disable_irq(tps->irq);
+	synchronize_irq(tps->irq);
+	disable_irq_wake(tps->irq);
+
+	tps65217_irq_cleanup(tps);
 }
 
 static const struct i2c_device_id tps65217_id_table[] = {
-- 
2.53.0