patch "iio: buffer: Fix memory leak in __iio_buffer_alloc_sysfs_and_mask()" added to char-misc-testing

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    iio: buffer: Fix memory leak in __iio_buffer_alloc_sysfs_and_mask()

to my char-misc git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-testing branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will be merged to the char-misc-next branch sometime soon,
after it passes testing, and the merge window is open.

If you have any questions about this process, please let me know.


From 9a2ff8009e53296e47de72d5af0bc31cd53274ff Mon Sep 17 00:00:00 2001
From: Yang Yingliang <yangyingliang@huawei.com>
Date: Wed, 13 Oct 2021 17:43:43 +0800
Subject: iio: buffer: Fix memory leak in __iio_buffer_alloc_sysfs_and_mask()

When iio_buffer_wrap_attr() returns NULL or buffer->buffer_group.name alloc
fails, the 'attr' which is allocated in __iio_buffer_alloc_sysfs_and_mask()
is not freed, and cause memory leak.

unreferenced object 0xffff888014882a00 (size 64):
  comm "i2c-adjd_s311-8", pid 424, jiffies 4294907737 (age 44.396s)
  hex dump (first 32 bytes):
    00 0f 8a 15 80 88 ff ff 00 0e 8a 15 80 88 ff ff  ................
    80 04 8a 15 80 88 ff ff 80 05 8a 15 80 88 ff ff  ................
  backtrace:
    [<0000000021752e67>] __kmalloc+0x1af/0x3c0
    [<0000000043e8305c>] iio_buffers_alloc_sysfs_and_mask+0xe73/0x1570 [industrialio]
    [<00000000b7aa5a17>] __iio_device_register+0x483/0x1a30 [industrialio]
    [<000000003fa0fb2f>] __devm_iio_device_register+0x23/0x90 [industrialio]
    [<000000003ab040cf>] adjd_s311_probe+0x19c/0x200 [adjd_s311]
    [<0000000080458969>] i2c_device_probe+0xa31/0xbe0
    [<00000000e20678ad>] really_probe+0x299/0xc30
    [<000000006bea9b27>] __driver_probe_device+0x357/0x500
    [<00000000e1df10d4>] driver_probe_device+0x4e/0x140
    [<0000000003661beb>] __device_attach_driver+0x257/0x340
    [<000000005bb4aa26>] bus_for_each_drv+0x166/0x1e0
    [<00000000272c5236>] __device_attach+0x272/0x420
    [<00000000d52a96ae>] bus_probe_device+0x1eb/0x2a0
    [<00000000129f7737>] device_add+0xbf0/0x1f90
    [<000000005eed4e52>] i2c_new_client_device+0x622/0xb20
    [<00000000b85a9c43>] new_device_store+0x1fa/0x420

This patch fix to free it before the error return.

Reported-by: Hulk Robot <hulkci@huawei.com>
Fixes: 15097c7a1adc ("iio: buffer: wrap all buffer attributes into iio_dev_attr")
Fixes: d9a625744ed0 ("iio: core: merge buffer/ & scan_elements/ attributes")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20211013094343.315275-1-yangyingliang@huawei.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/iio/industrialio-buffer.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index 55802da1deee..e2587237dbf9 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -1536,6 +1536,7 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer,
 		       sizeof(struct attribute *) * buffer_attrcount);
 
 	buffer_attrcount += ARRAY_SIZE(iio_buffer_attrs);
+	buffer->buffer_group.attrs = attr;
 
 	for (i = 0; i < buffer_attrcount; i++) {
 		struct attribute *wrapped;
@@ -1543,7 +1544,7 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer,
 		wrapped = iio_buffer_wrap_attr(buffer, attr[i]);
 		if (!wrapped) {
 			ret = -ENOMEM;
-			goto error_free_scan_mask;
+			goto error_free_buffer_attrs;
 		}
 		attr[i] = wrapped;
 	}
@@ -1558,8 +1559,6 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer,
 		goto error_free_buffer_attrs;
 	}
 
-	buffer->buffer_group.attrs = attr;
-
 	ret = iio_device_register_sysfs_group(indio_dev, &buffer->buffer_group);
 	if (ret)
 		goto error_free_buffer_attr_group_name;
-- 
2.33.1