From a8fbe284b25b1a6b3702769251c07e533b3840ad Mon Sep 17 00:00:00 2001 From: Joe Tsai Date: Wed, 18 Oct 2023 10:21:36 -0700 Subject: [PATCH] taildrop: fix theoretical race condition (#9866) WaitGroup.Wait should not be concurrently called WaitGroup.Add. In other words, we should not start new goroutines after shutodwn is called. Thus, add a conditional to check that shutdown has not been called before starting off a new waitAndDelete goroutine. Updates tailscale/corp#14772 Signed-off-by: Joe Tsai --- taildrop/delete.go | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/taildrop/delete.go b/taildrop/delete.go index 4f311d68b..a058e1a0a 100644 --- a/taildrop/delete.go +++ b/taildrop/delete.go @@ -94,7 +94,7 @@ func (d *fileDeleter) Insert(baseName string) { return // already queued for deletion } d.byName[baseName] = d.queue.PushBack(&deleteFile{baseName, d.clock.Now()}) - if d.queue.Len() == 1 { + if d.queue.Len() == 1 && d.shutdownCtx.Err() == nil { d.group.Go(func() { d.waitAndDelete(deleteDelay) }) } } @@ -147,7 +147,7 @@ func (d *fileDeleter) waitAndDelete(wait time.Duration) { } // If there are still some files to delete, retry again later. - if d.queue.Len() > 0 { + if d.queue.Len() > 0 && d.shutdownCtx.Err() == nil { file := d.queue.Front().Value.(*deleteFile) retryAfter := deleteDelay - now.Sub(file.inserted) d.group.Go(func() { d.waitAndDelete(retryAfter) })