[PATCH] powerpc: platforms: 52xx: Fix a resource leak in an error handling path

The error handling path of mpc52xx_lpbfifo_probe() and a request_irq() is
not balanced by a corresponding free_irq().

Add the missing call, as already done in the remove function.

Fixes: 3c9059d79f5e ("powerpc/5200: add LocalPlus bus FIFO device driver")
Signed-off-by: Christophe JAILLET <redacted>
---
Another strange thing is that the remove function has:
	/* Release the bestcomm transmit task */
	free_irq(bcom_get_task_irq(lpbfifo.bcom_tx_task), &lpbfifo);
but I've not been able to find a corresponding request_irq().

Is it dead code? Is there something missing in the probe?
(...Is it working?...)
---
 arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c b/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c
index b91ebebd9ff2..e0049b7df212 100644
--- a/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c
+++ b/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c

@@ -530,6 +530,7 @@ static int mpc52xx_lpbfifo_probe(struct platform_device *op)
  err_bcom_rx_irq:
 	bcom_gen_bd_rx_release(lpbfifo.bcom_rx_task);
  err_bcom_rx:
+	free_irq(lpbfifo.irq, &lpbfifo);
  err_irq:
 	iounmap(lpbfifo.regs);
 	lpbfifo.regs = NULL;

-- 
2.32.0

On Sat, 29 Jan 2022 08:16:04 +0100
Christophe JAILLET christophe.jaillet@wanadoo.fr wrote:

The error handling path of mpc52xx_lpbfifo_probe() and a request_irq() is
not balanced by a corresponding free_irq().

Add the missing call, as already done in the remove function.

Fixes: 3c9059d79f5e ("powerpc/5200: add LocalPlus bus FIFO device driver")
Signed-off-by: Christophe JAILLET <redacted>
---
Another strange thing is that the remove function has:
/* Release the bestcomm transmit task */
free_irq(bcom_get_task_irq(lpbfifo.bcom_tx_task), &lpbfifo);
but I've not been able to find a corresponding request_irq().

This driver does not request the tx task irq itself, but a fifo
client driver can request/free tx interrupts for submitted
fifo write tasks, like mpc5200 fec and pata drivers do, so
it is okay.

Is it dead code? Is there something missing in the probe?

No.

--
Anatolij

On Sat, Jan 29, 2022 at 08:16:04AM +0100, Christophe JAILLET wrote:

The error handling path of mpc52xx_lpbfifo_probe() and a request_irq() is
not balanced by a corresponding free_irq().

Add the missing call, as already done in the remove function.

Fixes: 3c9059d79f5e ("powerpc/5200: add LocalPlus bus FIFO device driver")
Signed-off-by: Christophe JAILLET <redacted>
---
Another strange thing is that the remove function has:
	/* Release the bestcomm transmit task */
	free_irq(bcom_get_task_irq(lpbfifo.bcom_tx_task), &lpbfifo);
but I've not been able to find a corresponding request_irq().

Is it dead code? Is there something missing in the probe?
(...Is it working?...)

I think you're right that the tx_task IRQ is never allocated.

I'm pretty sure that if you free a zero IRQ then it's a no-op.  It won't
find the 0 in the radix tree so irq_to_desc() returns NULL and free_irq()
returns early.

regards,
dan carpenter

On Sat, 29 Jan 2022 08:16:04 +0100, Christophe JAILLET wrote:

The error handling path of mpc52xx_lpbfifo_probe() and a request_irq() is
not balanced by a corresponding free_irq().

Add the missing call, as already done in the remove function.

Applied to powerpc/next.

[1/1] powerpc: platforms: 52xx: Fix a resource leak in an error handling path
      https://git.kernel.org/powerpc/c/5836947613ef33d311b4eff6a32d019580a214f5

cheers