Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

[release-21.0] Fix potential deadlock in health streamer (#17261) #17270

Merged
merged 1 commit into from
Nov 21, 2024
Merged

[release-21.0] Fix potential deadlock in health streamer (#17261) #17270

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 3 additions & 1 deletion go/vt/vttablet/tabletserver/health_streamer.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -293,8 +293,10 @@ func (hs *healthStreamer) SetUnhealthyThreshold(v time.Duration) {
// so it can read and write to the MySQL instance for schema-tracking.
func (hs *healthStreamer) MakePrimary(serving bool) {
hs.fieldsMu.Lock()
defer hs.fieldsMu.Unlock()
hs.isServingPrimary = serving
// We let go of the lock here because we don't want to hold the lock when calling RegisterNotifier.
// If we keep holding the lock, there is a potential deadlock that can happen.
hs.fieldsMu.Unlock()
// We register for notifications from the schema Engine only when schema tracking is enabled,
// and we are going to a serving primary state.
if serving && hs.signalWhenSchemaChange {
Expand Down
3 changes: 2 additions & 1 deletion go/vt/vttablet/tabletserver/health_streamer_test.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -563,13 +563,14 @@ func TestDeadlockBwCloseAndReload(t *testing.T) {

wg := sync.WaitGroup{}
wg.Add(2)
// Try running Close and reload in parallel multiple times.
// Try running Close & MakePrimary and reload in parallel multiple times.
// This reproduces the deadlock quite readily.
go func() {
defer wg.Done()
for i := 0; i < 100; i++ {
hs.Close()
hs.Open()
hs.MakePrimary(true)
}
}()

Expand Down
Loading