Description
Checklist
- I have searched the issue tracker for open issues that relate to the same problem, before opening a new one.
- This issue only relates to a single bug. I will open new issues for any other problems.
Describe the bug
UI can deadlock due to acquiring the same read lock twice in a single goroutine. If any other goroutine acquires the same lock for write between the two reads - the second read will hang and never release the first, meaning the entire UI deadlocks.
Here is the sequence that causes the double read lock:
# 0xe91ce4 sync.runtime_SemacquireRWMutexR+0x24 runtime/sema.go:82
# 0x14de187 sync.(*RWMutex).RLock+0x47 sync/rwmutex.go:70
# 0x14de163 fyne.io/fyne/v2/widget.(*BaseWidget).Visible+0x23 fyne.io/fyne/[email protected]/widget/widget.go:85
# 0x14a2a6d fyne.io/fyne/v2/widget.(*buttonRenderer).updateIconAndText+0x2d fyne.io/fyne/[email protected]/widget/button.go:396
# 0x14a14af fyne.io/fyne/v2/widget.(*Button).CreateRenderer+0x4cf fyne.io/fyne/[email protected]/widget/button.go:123
# 0x11892d7 fyne.io/fyne/v2/internal/cache.Renderer+0x117 fyne.io/fyne/[email protected]/internal/cache/widget.go:33
# 0x14de0f0 fyne.io/fyne/v2/widget.(*BaseWidget).MinSize+0x30 fyne.io/fyne/[email protected]/widget/widget.go:74
# 0x14a166e fyne.io/fyne/v2/widget.(*Button).MinSize+0x2e fyne.io/fyne/[email protected]/widget/button.go:148
# 0x1243181 fyne.io/fyne/v2/layout.hBoxLayout.MinSize+0x101 fyne.io/fyne/[email protected]/layout/boxlayout.go:203
# 0x11776b0 fyne.io/fyne/v2.(*Container).MinSize+0x50 fyne.io/fyne/[email protected]/container.go:90
# 0x124254a fyne.io/fyne/v2/layout.(*borderLayout).MinSize+0x2aa fyne.io/fyne/[email protected]/layout/borderlayout.go:91
# 0x11776b0 fyne.io/fyne/v2.(*Container).MinSize+0x50 fyne.io/fyne/[email protected]/container.go:90
# 0x124489a fyne.io/fyne/v2/layout.stackLayout.MinSize+0x9a fyne.io/fyne/[email protected]/layout/stacklayout.go:47
# 0x11776b0 fyne.io/fyne/v2.(*Container).MinSize+0x50 fyne.io/fyne/[email protected]/container.go:90
# 0x1242ba1 fyne.io/fyne/v2/layout.vBoxLayout.MinSize+0x101 fyne.io/fyne/[email protected]/layout/boxlayout.go:120
# 0x11776b0 fyne.io/fyne/v2.(*Container).MinSize+0x50 fyne.io/fyne/[email protected]/container.go:90
# 0x123a364 fyne.io/fyne/v2/internal/widget.(*SimpleRenderer).MinSize+0x24 fyne.io/fyne/[email protected]/internal/widget/simple_renderer.go:46
(*Button).CreateRenderer takes the propertyLock.RLock(), and so does (*BaseWidget).Visible which is further down the stacktrace.
How to reproduce
It is a race condition so it will be hard to reproduce without modifying the code to enforce the ordering that causes the deadlock. It is easy to see from the code that the possibility of deadlock exists. In my case - the thread waiting on the write lock was trying to call .Hide() on the button.
Screenshots
No response
Example code
No code needed.
Fyne version
2.5.0
Go compiler version
1.19.3
Operating system and version
Windows 10
Additional Information
No response
Activity