[PATCH] iio: buffer: Fix memory leak in iio_buffers_alloc_sysfs_and_mask()

[Yang Yingliang]

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
    [<00000000b721e9ec>] really_probe+0x285/0xc30
    [<00000000e6690642>] __driver_probe_device+0x35f/0x4f0
    [<000000003ee4152f>] driver_probe_device+0x4f/0x140
    [<0000000055cfdd2f>] __device_attach_driver+0x24c/0x330
    [<0000000098033282>] bus_for_each_drv+0x15d/0x1e0
    [<00000000fa1876f5>] __device_attach+0x267/0x410
    [<00000000838ca724>] bus_probe_device+0x1ec/0x2a0
    [<00000000f4ce978e>] device_add+0xc3d/0x2020
    [<000000000ee12e9b>] i2c_new_client_device+0x614/0xb00
    [<00000000fc5d3221>] new_device_store+0x1f4/0x410

Call iio_buffer_unregister_legacy_sysfs_groups() in error path
to fix this.

Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
Fixes: d9a625744ed0 ("iio: core: merge buffer/ & scan_elements/ attributes")
Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx>
---
 drivers/iio/industrialio-buffer.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index ae0912a14578..ba1c5c898e53 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -1630,7 +1630,7 @@ int iio_buffers_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
 	iio_dev_opaque->buffer_ioctl_handler = kzalloc(sz, GFP_KERNEL);
 	if (!iio_dev_opaque->buffer_ioctl_handler) {
 		ret = -ENOMEM;
-		goto error_unwind_sysfs_and_mask;
+		goto error_unregister_legacy_sysfs_groups;
 	}
 
 	iio_dev_opaque->buffer_ioctl_handler->ioctl = iio_device_buffer_ioctl;
@@ -1639,6 +1639,8 @@ int iio_buffers_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
 
 	return 0;
 
+error_unregister_legacy_sysfs_groups:
+	iio_buffer_unregister_legacy_sysfs_groups(indio_dev);
 error_unwind_sysfs_and_mask:
 	for (; unwind_idx >= 0; unwind_idx--) {
 		buffer = iio_dev_opaque->attached_buffers[unwind_idx];
-- 
2.25.1