[PATCH 5.14 191/849] iio: buffer: Fix memory leak in iio_buffers_alloc_sysfs_and_mask()

Greg Kroah-Hartman
2021-11-16T01:42:46Z

From: Yang Yingliang <yangyingliang@huawei.com>

commit 486a25084155bf633768c26f022201c051d6fd95 upstream.

When 'iio_dev_opaque->buffer_ioctl_handler' alloc fails in
iio_buffers_alloc_sysfs_and_mask(), the 'attrs' allocated in
iio_buffer_register_legacy_sysfs_groups() will be leaked:

unreferenced object 0xffff888108568d00 (size 128):
comm "88", pid 2014, jiffies 4294963294 (age 26.920s)
hex dump (first 32 bytes):
80 3e da 02 80 88 ff ff 00 3a da 02 80 88 ff ff .>.......:......
00 35 da 02 80 88 ff ff 00 38 da 02 80 88 ff ff .5.......8......
backtrace:
[<0000000095a9e51e>] __kmalloc+0x1a3/0x2f0
[<00000000faa3735e>] iio_buffers_alloc_sysfs_and_mask+0xfa3/0x1480 [industrialio]
[<00000000a46384dc>] __iio_device_register+0x52e/0x1b40 [industrialio]
[<00000000210af05e>] __devm_iio_device_register+0x22/0x80 [industrialio]
[<00000000730d7b41>] adjd_s311_probe+0x195/0x200 [adjd_s311]
[<00000000c0f70eb9>] i2c_device_probe+0xa07/0xbb0

The iio_buffer_register_legacy_sysfs_groups() is
called in __iio_buffer_alloc_sysfs_and_mask(),
so move the iio_buffer_unregister_legacy_sysfs_groups()
into __iio_buffer_free_sysfs_and_mask(), then the memory
will be freed.

Reported-by: Hulk Robot <hulkci@huawei.com>
Fixes: d9a625744ed0 ("iio: core: merge buffer/ & scan_elements/ attributes")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20211018063718.1971240-1-yangyingliang@huawei.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/iio/industrialio-buffer.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)

--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -1587,8 +1587,12 @@ error_cleanup_dynamic:
return ret;
}

-static void __iio_buffer_free_sysfs_and_mask(struct iio_buffer *buffer)
+static void __iio_buffer_free_sysfs_and_mask(struct iio_buffer *buffer,
+ struct iio_dev *indio_dev,
+ int index)
{
+ if (index == 0)
+ iio_buffer_unregister_legacy_sysfs_groups(indio_dev);
bitmap_free(buffer->scan_mask);
kfree(buffer->buffer_group.name);
kfree(buffer->buffer_group.attrs);
@@ -1642,7 +1646,7 @@ int iio_buffers_alloc_sysfs_and_mask(str
error_unwind_sysfs_and_mask:
for (; unwind_idx >= 0; unwind_idx--) {
buffer = iio_dev_opaque->attached_buffers[unwind_idx];
- __iio_buffer_free_sysfs_and_mask(buffer);
+ __iio_buffer_free_sysfs_and_mask(buffer, indio_dev, unwind_idx);
}
return ret;
}
@@ -1659,11 +1663,9 @@ void iio_buffers_free_sysfs_and_mask(str
iio_device_ioctl_handler_unregister(iio_dev_opaque->buffer_ioctl_handler);
kfree(iio_dev_opaque->buffer_ioctl_handler);

- iio_buffer_unregister_legacy_sysfs_groups(indio_dev);
-
for (i = iio_dev_opaque->attached_buffers_cnt - 1; i >= 0; i--) {
buffer = iio_dev_opaque->attached_buffers[i];
- __iio_buffer_free_sysfs_and_mask(buffer);
+ __iio_buffer_free_sysfs_and_mask(buffer, indio_dev, i);
}
}