Florian Weimer wrote: > > $ gcc -Wall -fpie -pie foo.c ; ./a.out > > initialization code > > > > $ gcc -Wall -fpie -pie foo.c -Wl,--no-as-needed -lpthread ; ./a.out > > multi-threaded initialization > > initialization code > > > > What will change for this program with glibc 2.34? > > If recompiled in this way: The presence of -lpthread will not matter, it > will always behave is if linked with -lpthread.
So it will print multi-threaded initialization initialization code in all cases. This is perfectly fine. > The relevant scenario here is LD_PRELOAD of a library that depends on > libpthread.so.0 ... > If not recompiled and linked without -lpthread against glibc 2.33 or > earlier, the behavior with the current glibc 2.34 snapshot is > architecture-dependent and also depends on the binutils version used for > linking the program. In some cases, calling pthread_once jumps to > address zero (causing a crash), or the call to pthread_once is elided > from the executable. This scenario can be emulated with older glibc > using LD_PRELOAD=libpthread.so.0. I'm confused again. Are you saying that the crash will occur when old binaries are being used with glibc 2.34 also *without* LD_PRELOAD? Bruno
