On Tue, 28 Jul 2015 10:15:00 -0700 Kees Cook <[email protected]> wrote:
> From: Ricky Zhou <[email protected]> > > Checking mm_users > 1 does not mean a process is multithreaded. For > example, reading /proc/PID/maps temporarily increments mm_users, allowing > other processes to (accidentally) interfere with unshare() calls. > > This fixes observed failures of unshare(CLONE_NEWUSER) incorrectly > returning EINVAL if another processes happened to be simultaneously > reading the maps file. Yikes. current_is_single_threaded() is expensive. Are we sure this isn't going to kill someone's workload? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
