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From: Dan Carpenter <dan.carpenter-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
To: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>,
	Ian Abbott <abbotti-GUHe90Wt2aFaa/9Udqfwiw@public.gmane.org>,
	Jiri Slaby <jslaby-IBi9RG/b67k@public.gmane.org>
Cc: Greg Kroah-Hartman
	<gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	"kernel-janitors-u79uwXL29TY76Z2rM5mHXA@public.gmane.org H
	Hartley Sweeten"
	<hsweeten-3FF4nKcrg1dE2c76skzGb0EOCMrvLtNR@public.gmane.org>,
	iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
	Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>
Subject: [PATCH] dma-mapping: remove an unnecessary NULL check
Date: Wed, 24 Apr 2019 17:24:37 +0300	[thread overview]
Message-ID: <20190424142437.GA29490@mwanda> (raw)

We already dereferenced "dev" when we called get_dma_ops() so this NULL
check is too late.  We're not supposed to pass NULL "dev" pointers to
dma_alloc_attrs().

Signed-off-by: Dan Carpenter <dan.carpenter-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
---
There are still at least two drivers which do pass a NULL unfortunately.

drivers/staging/comedi/drivers/comedi_isadma.c:195 comedi_isadma_alloc() error: NULL dereference inside function 'dma_alloc_coherent()'
drivers/staging/comedi/drivers/comedi_isadma.c:227 comedi_isadma_free() error: NULL dereference inside function 'dma_free_coherent()'
drivers/tty/synclink.c:3667 mgsl_alloc_buffer_list_memory() error: NULL dereference inside function 'dma_alloc_coherent()'
drivers/tty/synclink.c:3738 mgsl_free_buffer_list_memory() error: NULL dereference inside function 'dma_free_coherent()'
drivers/tty/synclink.c:3777 mgsl_alloc_frame_memory() error: NULL dereference inside function 'dma_alloc_coherent()'
drivers/tty/synclink.c:3811 mgsl_free_frame_memory() error: NULL dereference inside function 'dma_free_coherent()'

If I remember right there are one or two others which sometimes pass a
NULL, but it's harder to grep for those warnings.

 kernel/dma/mapping.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 685a53f2a793..f7afdadb6770 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -244,7 +244,7 @@ void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
 	const struct dma_map_ops *ops = get_dma_ops(dev);
 	void *cpu_addr;
 
-	WARN_ON_ONCE(dev && !dev->coherent_dma_mask);
+	WARN_ON_ONCE(!dev->coherent_dma_mask);
 
 	if (dma_alloc_from_dev_coherent(dev, size, dma_handle, &cpu_addr))
 		return cpu_addr;
-- 
2.18.0

WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <dan.carpenter@oracle.com>
To: Christoph Hellwig <hch@lst.de>, Ian Abbott <abbotti@mev.co.uk>,
	Jiri Slaby <jslaby@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-kernel@vger.kernel.org,
	"kernel-janitors@vger.kernel.org H Hartley Sweeten"
	<hsweeten@visionengravers.com>,
	iommu@lists.linux-foundation.org,
	Robin Murphy <robin.murphy@arm.com>
Subject: [PATCH] dma-mapping: remove an unnecessary NULL check
Date: Wed, 24 Apr 2019 17:24:37 +0300	[thread overview]
Message-ID: <20190424142437.GA29490@mwanda> (raw)
Message-ID: <20190424142437.k-CTNSB--nwKJelsZZhNszXAQgVrIjVWps7xQ0GEG98@z> (raw)

We already dereferenced "dev" when we called get_dma_ops() so this NULL
check is too late.  We're not supposed to pass NULL "dev" pointers to
dma_alloc_attrs().

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
There are still at least two drivers which do pass a NULL unfortunately.

drivers/staging/comedi/drivers/comedi_isadma.c:195 comedi_isadma_alloc() error: NULL dereference inside function 'dma_alloc_coherent()'
drivers/staging/comedi/drivers/comedi_isadma.c:227 comedi_isadma_free() error: NULL dereference inside function 'dma_free_coherent()'
drivers/tty/synclink.c:3667 mgsl_alloc_buffer_list_memory() error: NULL dereference inside function 'dma_alloc_coherent()'
drivers/tty/synclink.c:3738 mgsl_free_buffer_list_memory() error: NULL dereference inside function 'dma_free_coherent()'
drivers/tty/synclink.c:3777 mgsl_alloc_frame_memory() error: NULL dereference inside function 'dma_alloc_coherent()'
drivers/tty/synclink.c:3811 mgsl_free_frame_memory() error: NULL dereference inside function 'dma_free_coherent()'

If I remember right there are one or two others which sometimes pass a
NULL, but it's harder to grep for those warnings.

 kernel/dma/mapping.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 685a53f2a793..f7afdadb6770 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -244,7 +244,7 @@ void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
 	const struct dma_map_ops *ops = get_dma_ops(dev);
 	void *cpu_addr;
 
-	WARN_ON_ONCE(dev && !dev->coherent_dma_mask);
+	WARN_ON_ONCE(!dev->coherent_dma_mask);
 
 	if (dma_alloc_from_dev_coherent(dev, size, dma_handle, &cpu_addr))
 		return cpu_addr;
-- 
2.18.0

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <dan.carpenter@oracle.com>
To: Christoph Hellwig <hch@lst.de>, Ian Abbott <abbotti@mev.co.uk>,
	Jiri Slaby <jslaby@suse.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>,
	Robin Murphy <robin.murphy@arm.com>,
	iommu@lists.linux-foundation.org,
	"kernel-janitors@vger.kernel.org H Hartley Sweeten" 
	<hsweeten@visionengravers.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-kernel@vger.kernel.org
Subject: [PATCH] dma-mapping: remove an unnecessary NULL check
Date: Wed, 24 Apr 2019 17:24:37 +0300	[thread overview]
Message-ID: <20190424142437.GA29490@mwanda> (raw)

We already dereferenced "dev" when we called get_dma_ops() so this NULL
check is too late.  We're not supposed to pass NULL "dev" pointers to
dma_alloc_attrs().

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
There are still at least two drivers which do pass a NULL unfortunately.

drivers/staging/comedi/drivers/comedi_isadma.c:195 comedi_isadma_alloc() error: NULL dereference inside function 'dma_alloc_coherent()'
drivers/staging/comedi/drivers/comedi_isadma.c:227 comedi_isadma_free() error: NULL dereference inside function 'dma_free_coherent()'
drivers/tty/synclink.c:3667 mgsl_alloc_buffer_list_memory() error: NULL dereference inside function 'dma_alloc_coherent()'
drivers/tty/synclink.c:3738 mgsl_free_buffer_list_memory() error: NULL dereference inside function 'dma_free_coherent()'
drivers/tty/synclink.c:3777 mgsl_alloc_frame_memory() error: NULL dereference inside function 'dma_alloc_coherent()'
drivers/tty/synclink.c:3811 mgsl_free_frame_memory() error: NULL dereference inside function 'dma_free_coherent()'

If I remember right there are one or two others which sometimes pass a
NULL, but it's harder to grep for those warnings.

 kernel/dma/mapping.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 685a53f2a793..f7afdadb6770 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -244,7 +244,7 @@ void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
 	const struct dma_map_ops *ops = get_dma_ops(dev);
 	void *cpu_addr;
 
-	WARN_ON_ONCE(dev && !dev->coherent_dma_mask);
+	WARN_ON_ONCE(!dev->coherent_dma_mask);
 
 	if (dma_alloc_from_dev_coherent(dev, size, dma_handle, &cpu_addr))
 		return cpu_addr;
-- 
2.18.0


             reply	other threads:[~2019-04-24 14:24 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-24 14:24 Dan Carpenter [this message]
2019-04-24 14:24 ` [PATCH] dma-mapping: remove an unnecessary NULL check Dan Carpenter
2019-04-24 14:24 ` Dan Carpenter
2019-04-24 14:27 ` Christoph Hellwig
2019-04-24 14:27   ` Christoph Hellwig
2019-04-25 14:13   ` Ian Abbott
2019-04-25 14:13     ` Ian Abbott
2019-04-25 14:18     ` Christoph Hellwig
2019-04-25 14:18       ` Christoph Hellwig
2019-04-25 14:31       ` Ian Abbott
2019-04-25 14:31         ` Ian Abbott
2019-04-25 14:32         ` Christoph Hellwig
2019-04-25 14:32           ` Christoph Hellwig

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