| Message ID | 1528235011-30691-2-git-send-email-suzuki.poulose@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Suzuki, On Wednesday 06 June 2018 03:13 AM, Suzuki K Poulose wrote: > commit 6403587a930c ("coresight: use put_device() instead of kfree()") > introduced a memory leak where, if we fail to register the device > for coresight_device, we don't free the "coresight_device" object, > which was allocated via kzalloc(). Fix this by jumping to the > appropriate error path. put_device() will decrement the last reference and then free the memory by calling dev->release. Internally put_device() -> kobject_put() -> kobject_cleanup() which is responsible to call 'dev -> release' and also free other kobject resources. If you will see the coresight_device_release. There we are releasing all allocated memory. Still if you call kfree() again then it'll be redundancy. ~arvind > > Fixes: commit 6403587a930c ("coresight: use put_device() instead of kfree()") > Cc: Mathieu Poirier <mathieu.poirier@linaro.org> > Cc: Arvind Yadav <arvind.yadav.cs@gmail.com> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> > --- > drivers/hwtracing/coresight/coresight.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c > index 4969b32..2893cfe 100644 > --- a/drivers/hwtracing/coresight/coresight.c > +++ b/drivers/hwtracing/coresight/coresight.c > @@ -1020,7 +1020,7 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) > ret = device_register(&csdev->dev); > if (ret) { > put_device(&csdev->dev); > - goto err_kzalloc_csdev; > + goto err_kzalloc_refcnts; > } > > mutex_lock(&coresight_mutex);
On 06/06/2018 07:44 AM, Arvind Yadav wrote: > Hi Suzuki, > > > On Wednesday 06 June 2018 03:13 AM, Suzuki K Poulose wrote: >> commit 6403587a930c ("coresight: use put_device() instead of kfree()") >> introduced a memory leak where, if we fail to register the device >> for coresight_device, we don't free the "coresight_device" object, >> which was allocated via kzalloc(). Fix this by jumping to the >> appropriate error path. > put_device() will decrement the last reference and then > free the memory by calling dev->release. Internally > put_device() -> kobject_put() -> kobject_cleanup() which is > responsible to call 'dev -> release' and also free other kobject > resources. If you will see the coresight_device_release. There > we are releasing all allocated memory. Still if you call kfree() again > then it'll be redundancy. You're right. I think it would be good to have a comment explaining this to prevent this fix popping up in the future :-). I will add it Thanks Suzuki
diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c index 4969b32..2893cfe 100644 --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -1020,7 +1020,7 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) ret = device_register(&csdev->dev); if (ret) { put_device(&csdev->dev); - goto err_kzalloc_csdev; + goto err_kzalloc_refcnts; } mutex_lock(&coresight_mutex);
commit 6403587a930c ("coresight: use put_device() instead of kfree()") introduced a memory leak where, if we fail to register the device for coresight_device, we don't free the "coresight_device" object, which was allocated via kzalloc(). Fix this by jumping to the appropriate error path. Fixes: commit 6403587a930c ("coresight: use put_device() instead of kfree()") Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Arvind Yadav <arvind.yadav.cs@gmail.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> --- drivers/hwtracing/coresight/coresight.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)