On Mon, May 16, 2016 at 9:24 AM, Dmitry Safonov <[email protected]> wrote: > On 05/16/2016 04:54 PM, Ingo Molnar wrote: >> >> >> * Dmitry Safonov <[email protected]> wrote: >> >>> Should print on success: >>> [root@localhost ~]# ./test_mremap_vdso_32 >>> AT_SYSINFO_EHDR is 0xf773f000 >>> [NOTE] Moving vDSO: [f773f000, f7740000] -> [a000000, a001000] >>> [OK] >>> Or segfault if landing was bad (before patches): >>> [root@localhost ~]# ./test_mremap_vdso_32 >>> AT_SYSINFO_EHDR is 0xf774f000 >>> [NOTE] Moving vDSO: [f774f000, f7750000] -> [a000000, a001000] >>> Segmentation fault (core dumped) >> >> >> Can the segfault be caught and recovered from, to print a proper failure >> message? > > > Will add segfault handler, thanks. >
It may be more complicated that that. Glibc is likely to explode if this happens, and the headers are sufficiently screwed up that it's awkward to bypass glibc and call rt_sigaction directly. I have a test that does the latter, though, so it's at least possible, but I'm unconvinced it's worth it just for an error message. -- Andy Lutomirski AMA Capital Management, LLC
