2.6.31-stable review patch. If anyone has any objections, please let us know. ------------------ From: Peter Zijlstra commit fc6b177dee33365ccb29fe6d2092223cf8d679f9 upstream. The robust list pointers of user space held futexes are kept intact over an exec() call. When the exec'ed task exits exit_robust_list() is called with the stale pointer. The risk of corruption is minimal, but still it is incorrect to keep the pointers valid. Actually glibc should uninstall the robust list before calling exec() but we have to deal with it anyway. Nullify the pointers after [compat_]exit_robust_list() has been called. Reported-by: Anirban Sinha Signed-off-by: Peter Zijlstra Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- kernel/fork.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/kernel/fork.c +++ b/kernel/fork.c @@ -544,11 +544,15 @@ void mm_release(struct task_struct *tsk, /* Get rid of any futexes when releasing the mm */ #ifdef CONFIG_FUTEX - if (unlikely(tsk->robust_list)) + if (unlikely(tsk->robust_list)) { exit_robust_list(tsk); + tsk->robust_list = NULL; + } #ifdef CONFIG_COMPAT - if (unlikely(tsk->compat_robust_list)) + if (unlikely(tsk->compat_robust_list)) { compat_exit_robust_list(tsk); + tsk->compat_robust_list = NULL; + } #endif if (unlikely(!list_empty(&tsk->pi_state_list))) exit_pi_state_list(tsk); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/