Re: [PATCHv2] media: videobuf2-dma-contig: fix bad kfree in vb2_dma_contig_clear_max_seg_size
From: Marek Szyprowski <m.szyprowski@samsung.com>
Date: 2020-05-28 05:48:26
Also in:
lkml, stable
On 27.05.2020 10:23, Tomi Valkeinen wrote:
Commit 9495b7e92f716ab2bd6814fab5e97ab4a39adfdd ("driver core: platform:
Initialize dma_parms for platform devices") in v5.7-rc5 causes
vb2_dma_contig_clear_max_seg_size() to kfree memory that was not
allocated by vb2_dma_contig_set_max_seg_size().
The assumption in vb2_dma_contig_set_max_seg_size() seems to be that
dev->dma_parms is always NULL when the driver is probed, and the case
where dev->dma_parms has bee initialized by someone else than the driver
(by calling vb2_dma_contig_set_max_seg_size) will cause a failure.
All the current users of these functions are platform devices, which now
always have dma_parms set by the driver core. To fix the issue for v5.7,
make vb2_dma_contig_set_max_seg_size() return an error if dma_parms is
NULL to be on the safe side, and remove the kfree code from
vb2_dma_contig_clear_max_seg_size().
For v5.8 we should remove the two functions and move the
dma_set_max_seg_size() calls into the drivers.
Signed-off-by: Tomi Valkeinen <redacted>
Fixes: 9495b7e92f71 ("driver core: platform: Initialize dma_parms for platform devices")
Cc: stable@vger.kernel.orgAcked-by: Marek Szyprowski <m.szyprowski@samsung.com>
quoted hunk ↗ jump to hunk
--- Changes in v2: * vb2_dma_contig_clear_max_seg_size to empty static inline * Added cc: stable and fixes tag .../common/videobuf2/videobuf2-dma-contig.c | 20 ++----------------- include/media/videobuf2-dma-contig.h | 2 +- 2 files changed, 3 insertions(+), 19 deletions(-)diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c index d3a3ee5b597b..f4b4a7c135eb 100644 --- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c +++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c@@ -726,9 +726,8 @@ EXPORT_SYMBOL_GPL(vb2_dma_contig_memops); int vb2_dma_contig_set_max_seg_size(struct device *dev, unsigned int size) { if (!dev->dma_parms) { - dev->dma_parms = kzalloc(sizeof(*dev->dma_parms), GFP_KERNEL); - if (!dev->dma_parms) - return -ENOMEM; + dev_err(dev, "Failed to set max_seg_size: dma_parms is NULL\n"); + return -ENODEV; } if (dma_get_max_seg_size(dev) < size) return dma_set_max_seg_size(dev, size);@@ -737,21 +736,6 @@ int vb2_dma_contig_set_max_seg_size(struct device *dev, unsigned int size) } EXPORT_SYMBOL_GPL(vb2_dma_contig_set_max_seg_size); -/* - * vb2_dma_contig_clear_max_seg_size() - release resources for DMA parameters - * @dev: device for configuring DMA parameters - * - * This function releases resources allocated to configure DMA parameters - * (see vb2_dma_contig_set_max_seg_size() function). It should be called from - * device drivers on driver remove. - */ -void vb2_dma_contig_clear_max_seg_size(struct device *dev) -{ - kfree(dev->dma_parms); - dev->dma_parms = NULL; -} -EXPORT_SYMBOL_GPL(vb2_dma_contig_clear_max_seg_size); - MODULE_DESCRIPTION("DMA-contig memory handling routines for videobuf2"); MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>"); MODULE_LICENSE("GPL");diff --git a/include/media/videobuf2-dma-contig.h b/include/media/videobuf2-dma-contig.h index 5604818d137e..5be313cbf7d7 100644 --- a/include/media/videobuf2-dma-contig.h +++ b/include/media/videobuf2-dma-contig.h@@ -25,7 +25,7 @@ vb2_dma_contig_plane_dma_addr(struct vb2_buffer *vb, unsigned int plane_no) } int vb2_dma_contig_set_max_seg_size(struct device *dev, unsigned int size); -void vb2_dma_contig_clear_max_seg_size(struct device *dev); +static inline void vb2_dma_contig_clear_max_seg_size(struct device *dev) { } extern const struct vb2_mem_ops vb2_dma_contig_memops;
Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland