Ian, thanks for your explanation, it really shed light on that for me. I certainly will fix the data race.
Thanks to all for your time. On Tue, 19 Nov 2024 at 22:46, Ian Lance Taylor <i...@golang.org> wrote: > On Tue, Nov 19, 2024 at 3:50 AM Lin Lin <linsite.thin...@gmail.com> wrote: > > > > Thanks for your kind and instant reply. > > > > Allow me to explain myself a bit more. > > > > My code has two kinds of data races. First one is a global struct > without any pointer member being written and read by multiple Goroutines. > Second one is a struct's string member being written and read by multiple > Gourotines. Data race report shows no other unsafe or cgo usage. > > > > As far as I know, those kinds of data races may lead to a string or > struct value inconsistency within the race time window. How can that > inconsistency lead to a marked free bit in runtime.mspan? This really > puzzles me. > > Or maybe I took the wrong direction, this could be a hardware issue, > like a memory bit flip? But I failed to find any issue in the Go community. > > A data race in a string can confuse the garbage collector. A string > is a length and a pointer. If goroutine A updates the length in > parallel with goroutine B updating the pointer, then the garbage > collector can see a length and a pointer that do not correspond. If > the length is longer than the pointer expects, that can cause the GC > to mark some memory as allocated although it isn't. If that memory is > not possible to allocate, because it is part of the GC metadata, the > collector will crash. That is just one possible way to crash the > program with a race. > > As a practical matter, it's a waste of time to try to reason about GC > behavior when you know that the program has a race. As Kurtis says, > fix the race first. > > Ian > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/golang-nuts/CA%2BhP-7vPrZhv_1jABsUJV2N7uPTthQtDcKp6ng8q3tw3TGsFJw%40mail.gmail.com.
