sync.Map report concurrent map read and map write

[IcefireCgrbza]

Go version

1.20.8

Output of go env in your module/workspace:

so sorry i cant provide much infomation, maybe sensitive

What did you do?

sorry i can't upload the complete code, my code invoke (sync.Map).Store method and report an error, read and write the sync.map is concurrent

 fatal error: concurrent map read and map write

goroutine 2480 [running]:
sync.(*Map).Swap(0xc015bafdd0, {0x984e080, 0xc013614a50}, {0x9ab49e0, 0xc01235ceb8})
 /usr/local/go/src/sync/map.go:353 +0x205
sync.(*Map).Store(...)
 /usr/local/go/src/sync/map.go:155
...

What did you see happen?

fatal error: concurrent map read and map write

goroutine 2480 [running]:
sync.(*Map).Swap(0xc015bafdd0, {0x984e080, 0xc013614a50}, {0x9ab49e0, 0xc01235ceb8})
/usr/local/go/src/sync/map.go:353 +0x205
sync.(*Map).Store(...)
/usr/local/go/src/sync/map.go:155
...

What did you expect to see?

how to fix it

[gabyhelp]

Related Issues and Documentation

• runtime: fatal ERROR: concurrent map read and map write #26010 (closed)
• sync: Range reports concurrent map iterator and write #60216 (closed)
• sync: concurrent map iteration and map write on Map error #24112 (closed)
• sync: Map.Store() crash with fatal error: sync: unlock of unlocked mutex #26480 (closed)
• Map protected by mutex caused panic: concurrent map writes #20060 (closed)
• program crashes: concurrent map read and map write #20143 (closed)
• sync.Map has race(use reflect for container) #60813 (closed)
• go bug sync.Map #32641 (closed)
• sync.Map race conditions when calling Range() and Store() #22490 (closed)
• sync: Map has poor performance #28938 (closed)

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[cespare]

Hi @IcefireCgrbza!

It's possible you've found a bug in Go, but it's more likely that there's a problem with your code. It will be hard to figure it out without some more details, though. For a start, can you include:

1. More of the stack trace (in particular, both of the stack traces that indicate the map read and the map write)
2. A bit of code that demonstrates how you're using sync.Map in some way

Is it possible that you're copying the sync.Map after you start using it? That is not okay (see the Map documentation). That should be caught by go vet.

[IcefireCgrbza]

thanks, go vet help find the code bug, sync.Map is copy by struct method definication