diff options
author | Laurent Pinchart <laurent.pinchart@ideasonboard.com> | 2024-01-19 17:29:58 +0200 |
---|---|---|
committer | Laurent Pinchart <laurent.pinchart@ideasonboard.com> | 2024-01-25 02:39:05 +0200 |
commit | f422624d9c47b6f81c00d4b9fe2719b545b1392a (patch) | |
tree | 594e9841b5e70bfd2259769afffc10652f4a5284 /src | |
parent | d47fa37c2e22c0ef13be69c00950fe39f257e2bb (diff) |
libcamera: thread: Ensure deferred deletion of all objects before stopping
Objects can be scheduled for deletion with Object::deleteLater(), which
queues a deferred deletion to the thread's event loop. As the
deleteLater() function is meant to be called from a different thread,
this may race with thread termination, and deferred deletions queued
just before calling Thread::exit() may not be processed by the event
loop. Make sure they get processed when finishing the thread, before
stopping.
This eliminates the race condition that occurs when calling
Object::deleteLater() followed by Thread::exit() from the same thread.
Calling deleteLater() from neither the thread the object is bound to or
the thread calling Thread::exit() is still inherently racy.
The change fixes a failure in the object-delete unit test.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Milan Zamazal <mzamazal@redhat.com>
Diffstat (limited to 'src')
-rw-r--r-- | src/libcamera/base/object.cpp | 5 | ||||
-rw-r--r-- | src/libcamera/base/thread.cpp | 6 |
2 files changed, 9 insertions, 2 deletions
diff --git a/src/libcamera/base/object.cpp b/src/libcamera/base/object.cpp index 1fce5a2a..14399d75 100644 --- a/src/libcamera/base/object.cpp +++ b/src/libcamera/base/object.cpp @@ -116,8 +116,9 @@ Object::~Object() * event loop that the object belongs to. This ensures the object is destroyed * from the right context, as required by the libcamera threading model. * - * If this function is called before the thread's event loop is started, the - * object will be deleted when the event loop starts. + * If this function is called before the thread's event loop is started or after + * it has stopped, the object will be deleted when the event loop (re)starts. If + * this never occurs, the object will be leaked. * * Deferred deletion can be used to control the destruction context with shared * pointers. An object managed with shared pointers is deleted when the last diff --git a/src/libcamera/base/thread.cpp b/src/libcamera/base/thread.cpp index 75693c92..4ac72036 100644 --- a/src/libcamera/base/thread.cpp +++ b/src/libcamera/base/thread.cpp @@ -371,6 +371,12 @@ void Thread::run() void Thread::finishThread() { + /* + * Objects may have been scheduled for deletion right before the thread + * exited. Ensure they get deleted now, before the thread stops. + */ + dispatchMessages(Message::Type::DeferredDelete); + data_->mutex_.lock(); data_->running_ = false; data_->mutex_.unlock(); |