[PATCH] (powerpc/512) Fix possible `dma_unmap_single()` on uninitialized pointer

Subsystems: linux for powerpc (32-bit and 64-bit), linux for powerpc embedded mpc5xxx, the rest

STALE431d

3 messages, 3 authors, 2025-06-09 · open the first message on its own page

[PATCH] (powerpc/512) Fix possible `dma_unmap_single()` on uninitialized pointer

From: Thomas Fourier <hidden>
Date: 2025-06-05 16:39:39

If the device configuration fails (if `dma_dev->device_config()`),
`sg_dma_address(&sg)` is not initialized and the jump to `err_dma_prep`
leads to calling `dma_unmap_single()` on `sg_dma_address(&sg)`.

Signed-off-by: Thomas Fourier <redacted>
---
 arch/powerpc/platforms/512x/mpc512x_lpbfifo.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/512x/mpc512x_lpbfifo.c b/arch/powerpc/platforms/512x/mpc512x_lpbfifo.c
index 9668b052cd4b..ef3be438f914 100644
--- a/arch/powerpc/platforms/512x/mpc512x_lpbfifo.c
+++ b/arch/powerpc/platforms/512x/mpc512x_lpbfifo.c

@@ -241,8 +241,7 @@ static int mpc512x_lpbfifo_kick(void)
 
 	/* Make DMA channel work with LPB FIFO data register */
 	if (dma_dev->device_config(lpbfifo.chan, &dma_conf)) {
-		ret = -EINVAL;
-		goto err_dma_prep;
+		return -EINVAL;
 	}
 
 	sg_init_table(&sg, 1);

-- 
2.43.0

Re: [PATCH] (powerpc/512) Fix possible `dma_unmap_single()` on uninitialized pointer

From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2025-06-09 00:50:10

Thomas Fourier [off-list ref] writes:

quoted hunk

If the device configuration fails (if `dma_dev->device_config()`),
`sg_dma_address(&sg)` is not initialized and the jump to `err_dma_prep`
leads to calling `dma_unmap_single()` on `sg_dma_address(&sg)`.

Signed-off-by: Thomas Fourier <redacted>
---
 arch/powerpc/platforms/512x/mpc512x_lpbfifo.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/512x/mpc512x_lpbfifo.c b/arch/powerpc/platforms/512x/mpc512x_lpbfifo.c
index 9668b052cd4b..ef3be438f914 100644
--- a/arch/powerpc/platforms/512x/mpc512x_lpbfifo.c
+++ b/arch/powerpc/platforms/512x/mpc512x_lpbfifo.c

@@ -241,8 +241,7 @@ static int mpc512x_lpbfifo_kick(void)
 
 	/* Make DMA channel work with LPB FIFO data register */
 	if (dma_dev->device_config(lpbfifo.chan, &dma_conf)) {
-		ret = -EINVAL;
-		goto err_dma_prep;
+		return -EINVAL;
 	}
 
 	sg_init_table(&sg, 1);

Yep looks good. That's the first use of goto for error handling, and
it's clearly too early. All the previous error cases do a direct return.

Reviewed-by: Michael Ellerman <mpe@ellerman.id.au>

cheers

Re: [PATCH] (powerpc/512) Fix possible `dma_unmap_single()` on uninitialized pointer

From: Christophe Leroy <hidden>
Date: 2025-06-09 07:50:36


Le 05/06/2025 à 18:37, Thomas Fourier a écrit :

quoted hunk

[Vous ne recevez pas souvent de courriers de fourier.thomas@gmail.com. Découvrez pourquoi ceci est important à https://aka.ms/LearnAboutSenderIdentification ]

If the device configuration fails (if `dma_dev->device_config()`),
`sg_dma_address(&sg)` is not initialized and the jump to `err_dma_prep`
leads to calling `dma_unmap_single()` on `sg_dma_address(&sg)`.

Signed-off-by: Thomas Fourier <redacted>
---
  arch/powerpc/platforms/512x/mpc512x_lpbfifo.c | 3 +--
  1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/512x/mpc512x_lpbfifo.c b/arch/powerpc/platforms/512x/mpc512x_lpbfifo.c
index 9668b052cd4b..ef3be438f914 100644
--- a/arch/powerpc/platforms/512x/mpc512x_lpbfifo.c
+++ b/arch/powerpc/platforms/512x/mpc512x_lpbfifo.c

@@ -241,8 +241,7 @@ static int mpc512x_lpbfifo_kick(void)

         /* Make DMA channel work with LPB FIFO data register */
         if (dma_dev->device_config(lpbfifo.chan, &dma_conf)) {
-               ret = -EINVAL;
-               goto err_dma_prep;
+               return -EINVAL;
         }

You should remove the { } as it is now a single line.

         sg_init_table(&sg, 1);
--
2.43.0

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