On Tue, Jun 28, 2016 at 4:35 AM, Dmitry Safonov <[email protected]> wrote: > Add possibility for userspace 32-bit applications to move > vdso mapping. Previously, when userspace app called > mremap for vdso, in return path it would land on previous > address of vdso page, resulting in segmentation violation. > Now it lands fine and returns to userspace with remapped vdso. > This will also fix context.vdso pointer for 64-bit, which does not > affect the user of vdso after mremap by now, but this may change. > > As suggested by Andy, return EINVAL for mremap that splits vdso image. > > Renamed and moved text_mapping structure declaration inside > map_vdso, as it used only there and now it complement > vvar_mapping variable. > > There is still problem for remapping vdso in glibc applications: > linker relocates addresses for syscalls on vdso page, so > you need to relink with the new addresses. Or the next syscall > through glibc may fail: > Program received signal SIGSEGV, Segmentation fault. > #0 0xf7fd9b80 in __kernel_vsyscall () > #1 0xf7ec8238 in _exit () from /usr/lib32/libc.so.6
Acked-by: Andy Lutomirski <[email protected]>
