Unable to provide possible suspect using Predator, CL and Code Search.
Could someone please look into the issue.

Thank You...

Tommy, I'm not actively working on Textfield, can you investigate or find another owner?
Looks like a nested call to OnBeforeUserAction, or a failure to call OnAfterUserAction somewhere.
Nothing appears amiss from a quick look, and my attempts to run clusterfuzz locally didn't repro.
If needed, it might make sense to add some logging at callsites, or record the holder of the lock.

msw: Sounds good. I'm guessing I'm as good of an owner for this bug as anyone else then.

I will get to this when I have a chance. :)

Oh boy this is not good.

The root cause is that middle-click triggers a selection-paste on Linux.

The way we implement that, we fire up a RunLoop within ui::SelectionRequestor::BlockTillSelectionNotifyForRequest to make an asynchronous operation blocking.

Then, during this RunLoop, we (unintentionally) process the next user gesture, leading to nested user actions, leading to this crash. 

The sequence of gestures looks like:

Running: xdotool windowactivate --sync 125829121
.
Running: xdotool mouseup -- 1
.
Running: xdotool mousemove --sync -- 730 60
.
Running: xdotool click --repeat 3 -- 2


A root cause fix would be to make selection-paste not fire up an inner run loop.

ClusterFuzz testcase 5162746258391040 appears to be flaky, updating reproducibility label.

ClusterFuzz testcase 5162746258391040 is flaky and no longer crashes, so closing issue.

If this is incorrect, please add ClusterFuzz-Wrong label and re-open the issue.