| Message ID | 20221124085448.3620240-1-yangyingliang@huawei.com |
|---|---|
| State | New |
| Headers | show |
| Series | i2c: core: Fix possible memleak in i2c_new_client_device() | expand |
On Thu, Nov 24, 2022 at 04:54:48PM +0800, Yang Yingliang wrote: > I got memory leak as follows when doing fault injection test: > > unreferenced object 0xffff888014aec078 (size 8): > comm "xrun", pid 356, jiffies 4294910619 (age 16.332s) > hex dump (first 8 bytes): > 31 2d 30 30 31 63 00 00 1-001c.. > backtrace: > [<00000000eb56c0a9>] __kmalloc_track_caller+0x1a6/0x300 > [<000000000b220ea3>] kvasprintf+0xad/0x140 > [<00000000b83203e5>] kvasprintf_const+0x62/0x190 > [<000000002a5eab37>] kobject_set_name_vargs+0x56/0x140 > [<00000000300ac279>] dev_set_name+0xb0/0xe0 > [<00000000b66ebd6f>] i2c_new_client_device+0x7e4/0x9a0 > > If device_register() returns error in i2c_new_client_device(), > the name allocated by i2c_dev_set_name() need be freed. As > comment of device_register() says, it should use put_device() > to give up the reference in the error path. > > Moving i2c_dev_set_name() to front of device_register(), so > it's managed by device core, then call put_device(), when the > refcount is 0, the name will be freed in kobject_cleanup() and > the 'client' will be freed in i2c_client_dev_release(). > > Because the 'client' is freed by calling put_device(), so it > don't need goto error label, release other resources before > put_device() and return directly. > > Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> The report seems correct to me, yet the solution is copying code a tad too much IMO. I'll send another approach I'd suggest to spark some discussion. Thanks for the report in any case!
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index b4edf10e8fd0..161bf28f2d87 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -954,7 +954,6 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf client->dev.fwnode = info->fwnode; device_enable_async_suspend(&client->dev); - i2c_dev_set_name(adap, client, info); if (info->swnode) { status = device_add_software_node(&client->dev, info->swnode); @@ -966,17 +965,23 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf } } + i2c_dev_set_name(adap, client, info); status = device_register(&client->dev); - if (status) - goto out_remove_swnode; + if (status) { + device_remove_software_node(&client->dev); + of_node_put(info->of_node); + dev_err(&adap->dev, + "Failed to register i2c client %s at 0x%02x (%d)\n", + client->name, client->addr, status); + put_device(&client->dev); + return ERR_PTR(status); + } dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n", client->name, dev_name(&client->dev)); return client; -out_remove_swnode: - device_remove_software_node(&client->dev); out_err_put_of_node: of_node_put(info->of_node); out_err:
I got memory leak as follows when doing fault injection test: unreferenced object 0xffff888014aec078 (size 8): comm "xrun", pid 356, jiffies 4294910619 (age 16.332s) hex dump (first 8 bytes): 31 2d 30 30 31 63 00 00 1-001c.. backtrace: [<00000000eb56c0a9>] __kmalloc_track_caller+0x1a6/0x300 [<000000000b220ea3>] kvasprintf+0xad/0x140 [<00000000b83203e5>] kvasprintf_const+0x62/0x190 [<000000002a5eab37>] kobject_set_name_vargs+0x56/0x140 [<00000000300ac279>] dev_set_name+0xb0/0xe0 [<00000000b66ebd6f>] i2c_new_client_device+0x7e4/0x9a0 If device_register() returns error in i2c_new_client_device(), the name allocated by i2c_dev_set_name() need be freed. As comment of device_register() says, it should use put_device() to give up the reference in the error path. Moving i2c_dev_set_name() to front of device_register(), so it's managed by device core, then call put_device(), when the refcount is 0, the name will be freed in kobject_cleanup() and the 'client' will be freed in i2c_client_dev_release(). Because the 'client' is freed by calling put_device(), so it don't need goto error label, release other resources before put_device() and return directly. Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- drivers/i2c/i2c-core-base.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-)