On Fri, Jan 19, 2024 at 1:18 PM Song Liu <song@xxxxxxxxxx> wrote: > > On Fri, Jan 19, 2024 at 1:02 PM Andrii Nakryiko <andrii@xxxxxxxxxx> wrote: > > > > We've ran into issues with using dup2() API in production setting, where > > libbpf is linked into large production environment and ends up calling > > uninteded custom implementations of dup2(). These custom implementations > > typo: unintended oops, but probably doesn't warrant respinning > > > don't provide atomic FD replacement guarantees of dup2() syscall, > > leading to subtle and hard to debug issues. > > > > To prevent this in the future and guarantee that no libc implementation > > will do their own custom non-atomic dup2() implementation, call dup2() > > syscall directly with syscall(SYS_dup2). > > > > Note that some architectures don't seem to provide dup2 and have dup3 > > instead. Try to detect and pick best syscall. > > I wonder whether we can just always use dup3(). dup3() (according to my git foo) was added in 4.17, which is more modern than some other usable BPF, so I don't want to just randomly bump the minimal supported (by libbpf) kernel for something like this. > > > Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx> > > Acked-by: Song Liu <song@xxxxxxxxxx> > > [...]
