On 1/7/25 9:30 PM, Ma Ke wrote:
Once device_register() failed, we should call put_device() to decrement reference count for cleanup. Or it could cause memory leak. device_register() includes device_add(). As comment of device_add() says, 'if device_add() succeeds, you should call device_del() when you want to get rid of it. If device_add() has not succeeded, use only put_device() to drop the reference count'.
And above device_register() it says: * NOTE: _Never_ directly free @dev after calling this function, even * if it returned an error! Always use put_device() to give up the * reference initialized in this function instead.
Found by code review.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Ma Ke <make24@xxxxxxxxxxx>
Looks good to me. Much cleaner result. Reviewed-by: Alex Elder <elder@xxxxxxxxxx>
--- Changes in v4: - deleted the redundant initialization; Changes in v3: - modified the patch as suggestions; Changes in v2: - modified the patch as suggestions. --- arch/arm/common/locomo.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) diff --git a/arch/arm/common/locomo.c b/arch/arm/common/locomo.c index cb6ef449b987..45106066a17f 100644 --- a/arch/arm/common/locomo.c +++ b/arch/arm/common/locomo.c @@ -223,10 +223,8 @@ locomo_init_one_child(struct locomo *lchip, struct locomo_dev_info *info) int ret;dev = kzalloc(sizeof(struct locomo_dev), GFP_KERNEL);- if (!dev) { - ret = -ENOMEM; - goto out; - } + if (!dev) + return -ENOMEM;/** If the parent device has a DMA mask associated with it, @@ -254,10 +252,9 @@ locomo_init_one_child(struct locomo *lchip, struct locomo_dev_info *info) NO_IRQ : lchip->irq_base + info->irq[0];ret = device_register(&dev->dev);- if (ret) { - out: - kfree(dev); - } + if (ret) + put_device(&dev->dev); + return ret; }
