From: Jonathan Cameron <jic23@kernel.org>
To: Alexandru Ardelean <ardeleanalex@gmail.com>
Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org,
Alexandru Ardelean <alexandru.ardelean@analog.com>
Subject: Re: [PATCH v2] iio: core: use kstrdup_const/kfree_const for buffer attributes
Date: Sat, 27 Feb 2021 17:49:52 +0000 [thread overview]
Message-ID: <20210227174952.06f45503@archlinux> (raw)
In-Reply-To: <20210223072926.79590-1-alexandru.ardelean@analog.com>
On Tue, 23 Feb 2021 09:29:26 +0200
Alexandru Ardelean <ardeleanalex@gmail.com> wrote:
> When the buffer attributes were wrapped in iio_dev_attr types, I forgot to
> duplicate the names, so that when iio_free_chan_devattr_list() gets called
> on cleanup, these get free'd.
> I stumbled over this while accidentally breaking a driver doing
> iio_device_register(), and then the issue appeared.
>
> Some ways to fix this are:
> 1. Just use kstrdup() during iio_buffer_wrap_attr()
> 2. Just use kfree_const() during iio_free_chan_devattr_list
> 3. Use both kstrdup_const() & kfree_const() (in the places mentioned above)
>
> This implements the third option, as it allows some users/drivers to
> specify some attributes allocated on the heap.
>
> Fixes: a1a11142f66c ("iio: buffer: wrap all buffer attributes into iio_dev_attr")
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
> ---
> drivers/iio/industrialio-buffer.c | 1 +
> drivers/iio/industrialio-core.c | 2 +-
> 2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
> index 5d641f8adfbd..ac882e60c419 100644
> --- a/drivers/iio/industrialio-buffer.c
> +++ b/drivers/iio/industrialio-buffer.c
> @@ -1306,6 +1306,7 @@ static struct attribute *iio_buffer_wrap_attr(struct iio_buffer *buffer,
> return NULL;
>
> iio_attr->buffer = buffer;
> + iio_attr->dev_attr.attr.name = kstrdup_const(attr->name, GFP_KERNEL);
> memcpy(&iio_attr->dev_attr, dattr, sizeof(iio_attr->dev_attr));
Doesn't this wipe out the duplicated string? I swapped the two lines above
which I think should avoid that.
Merged into original patch
Jonathan
>
> list_add(&iio_attr->l, &buffer->buffer_attr_list);
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index 0d8c6e88d993..cb2735d2ae4b 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -1358,7 +1358,7 @@ void iio_free_chan_devattr_list(struct list_head *attr_list)
> struct iio_dev_attr *p, *n;
>
> list_for_each_entry_safe(p, n, attr_list, l) {
> - kfree(p->dev_attr.attr.name);
> + kfree_const(p->dev_attr.attr.name);
> list_del(&p->l);
> kfree(p);
> }
next prev parent reply other threads:[~2021-02-27 17:56 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-19 8:58 [PATCH 0/2] iio: core,buffer-dma: 2 fixes for the recent IIO buffer series Alexandru Ardelean
2021-02-19 8:58 ` [PATCH 1/2] iio: core: use kfree_const in iio_free_chan_devattr_list() to free names Alexandru Ardelean
2021-02-22 16:01 ` Jonathan Cameron
2021-02-23 6:36 ` Alexandru Ardelean
2021-02-23 7:29 ` [PATCH v2] iio: core: use kstrdup_const/kfree_const for buffer attributes Alexandru Ardelean
2021-02-27 17:49 ` Jonathan Cameron [this message]
2021-02-19 8:58 ` [PATCH 2/2] iio: buffer-dma: fix type of 'i' in iio_dma_buffer_alloc_blocks() Alexandru Ardelean
2021-02-21 11:55 ` [PATCH 0/2] iio: core,buffer-dma: 2 fixes for the recent IIO buffer series Jonathan Cameron
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