From: Yang Yingliang yangyingliang@huawei.com
commit efa17e90e1711bdb084e3954fa44afb6647331c0 upstream.
dev_set_name() allocates memory for name, it need be freed when device_add() fails, call put_device() to give up the reference that hold in device_initialize(), so that it can be freed in kobject_cleanup() when the refcount hit to 0.
Fault injection test can trigger this:
unreferenced object 0xffff8e8340a7b4c0 (size 32): comm "modprobe", pid 243, jiffies 4294678145 (age 48.845s) hex dump (first 32 bytes): 69 69 6f 5f 73 79 73 66 73 5f 74 72 69 67 67 65 iio_sysfs_trigge 72 00 a7 40 83 8e ff ff 00 86 13 c4 f6 ee ff ff r..@............ backtrace: [<0000000074999de8>] __kmem_cache_alloc_node+0x1e9/0x360 [<00000000497fd30b>] __kmalloc_node_track_caller+0x44/0x1a0 [<000000003636c520>] kstrdup+0x2d/0x60 [<0000000032f84da2>] kobject_set_name_vargs+0x1e/0x90 [<0000000092efe493>] dev_set_name+0x4e/0x70
Fixes: 1f785681a870 ("staging:iio:trigger sysfs userspace trigger rework.") Signed-off-by: Yang Yingliang yangyingliang@huawei.com Cc: Stable@vger.kernel.org Link: https://lore.kernel.org/r/20221022074212.1386424-1-yangyingliang@huawei.com Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iio/trigger/iio-trig-sysfs.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
--- a/drivers/iio/trigger/iio-trig-sysfs.c +++ b/drivers/iio/trigger/iio-trig-sysfs.c @@ -211,9 +211,13 @@ static int iio_sysfs_trigger_remove(int
static int __init iio_sysfs_trig_init(void) { + int ret; device_initialize(&iio_sysfs_trig_dev); dev_set_name(&iio_sysfs_trig_dev, "iio_sysfs_trigger"); - return device_add(&iio_sysfs_trig_dev); + ret = device_add(&iio_sysfs_trig_dev); + if (ret) + put_device(&iio_sysfs_trig_dev); + return ret; } module_init(iio_sysfs_trig_init);