> Still, memory leaks are possible if the program forgets about a > pointer to some piece of memory no longer needed, and keeps that > pointer in say some global structure. Such memory leaks would not be > found using address sanitizer.
We had a few cases of this in the past. Given the difficulty of tracing the leaking references, we wrote this package for taking snapshots of the R heap and finding dominators and shortest paths between nodes: Repo: https://github.com/r-lib/memtools Vignette: https://memtools.r-lib.org/articles/memtools.html One issue that complicates taking snapshots is that R doesn't expose the GC roots. In practice, only the precious list is needed I think. Would you consider a patch that allows retrieving the precious list for debugging purposes via a `.Internal()` call? Best, Lionel On 3/15/21, Tomas Kalibera <tomas.kalib...@gmail.com> wrote: > On 3/12/21 7:43 PM, xiaoyan yu wrote: >> I am writing C++ program based on R extensions and also try to test the >> program with google address sanitizer. >> >> I thought if I don't protect the variable from the allocation API such as >> Rf_allocVector, there will be a memory leak. However, the address >> sanitizer >> didn't report it. Is my understanding correct? Or I will see the memory >> leak only if I compile R source code with the address sanitizer. > > Yes, you should use special options for compilation and linking to use > address sanitizer. See Writing R Extensions, section 4.3.3. > > If you allocate an R object using Rf_allocVector(), but don't protect > it, it means this object is available for the garbage collector to > reclaim. So it is not a memory leak. > > Memory leaks with a garbage collector are much less common than without, > because if the program loses a pointer to some piece of memory, that > piece will automatically be reclaimed (not leaked). Still, memory leaks > are possible if the program forgets about a pointer to some piece of > memory no longer needed, and keeps that pointer in say some global > structure. Such memory leaks would not be found using address sanitizer. > > Address sanitizer/Undefined behavior sanitizer can sometimes find errors > caused by that the program forgets to protect an R object, but this is > relatively rare, as they don't understand R heap specifically, so you > cannot assume that if you create such example, the error will always be > found. > > Best > Tomas > >> >> Please help! >> >> Thanks, >> Xiaoyan >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-devel@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-devel > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel > ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
