The patch titled wait_task_continued/zombie: don't use task_pid_nr_ns() lockless has been added to the -mm tree. Its filename is wait_task_continued-zombie-dont-use-task_pid_nr_ns-lockless.patch *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this ------------------------------------------------------ Subject: wait_task_continued/zombie: don't use task_pid_nr_ns() lockless From: Oleg Nesterov <oleg@xxxxxxxxxx> Surprise, other 2 wait_task_() functions also abuse task_pid_nr_ns(). May cause read-after-free or report nr == 0 in wait_task_continued(). wait_task_zombie() doesn't have this problem, but still it is better to cache pid_t rather than call task_pid_nr_ns() 3 times on the saved pid_namespace. Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: Roland McGrath <roland@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/exit.c | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) diff -puN kernel/exit.c~wait_task_continued-zombie-dont-use-task_pid_nr_ns-lockless kernel/exit.c --- a/kernel/exit.c~wait_task_continued-zombie-dont-use-task_pid_nr_ns-lockless +++ a/kernel/exit.c @@ -1186,12 +1186,9 @@ static int wait_task_zombie(struct task_ { unsigned long state; int retval, status, traced; - struct pid_namespace *ns; - - ns = current->nsproxy->pid_ns; + pid_t pid = task_pid_nr_ns(p, current->nsproxy->pid_ns); if (unlikely(noreap)) { - pid_t pid = task_pid_nr_ns(p, ns); uid_t uid = p->uid; int exit_code = p->exit_code; int why, status; @@ -1310,11 +1307,11 @@ static int wait_task_zombie(struct task_ retval = put_user(status, &infop->si_status); } if (!retval && infop) - retval = put_user(task_pid_nr_ns(p, ns), &infop->si_pid); + retval = put_user(pid, &infop->si_pid); if (!retval && infop) retval = put_user(p->uid, &infop->si_uid); if (!retval) - retval = task_pid_nr_ns(p, ns); + retval = pid; if (traced) { write_lock_irq(&tasklist_lock); @@ -1433,7 +1430,6 @@ static int wait_task_continued(struct ta int retval; pid_t pid; uid_t uid; - struct pid_namespace *ns; if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) return 0; @@ -1448,8 +1444,7 @@ static int wait_task_continued(struct ta p->signal->flags &= ~SIGNAL_STOP_CONTINUED; spin_unlock_irq(&p->sighand->siglock); - ns = current->nsproxy->pid_ns; - pid = task_pid_nr_ns(p, ns); + pid = task_pid_nr_ns(p, current->nsproxy->pid_ns); uid = p->uid; get_task_struct(p); read_unlock(&tasklist_lock); @@ -1460,7 +1455,7 @@ static int wait_task_continued(struct ta if (!retval && stat_addr) retval = put_user(0xffff, stat_addr); if (!retval) - retval = task_pid_nr_ns(p, ns); + retval = pid; } else { retval = wait_noreap_copyout(p, pid, uid, CLD_CONTINUED, SIGCONT, _ Patches currently in -mm which might be from oleg@xxxxxxxxxx are wait_task_stopped-dont-use-task_pid_nr_ns-lockless.patch proc-remove-races-from-proc_id_readdir.patch wait_task_stopped-pass-correct-exit_code-to.patch use-__set_task_state-for-traced-stopped-tasks.patch add-task_wakekill.patch do_wait-remove-one-else-if-branch.patch proc-implement-proc_single_file_operations.patch proc-rewrite-do_task_stat-to-correctly-handle-pid-namespaces.patch proc-seqfile-convert-proc_pid_statm.patch proc-proper-pidns-handling-for-proc-self.patch proc-fix-the-threaded-proc-self.patch kill-pt_attached.patch kill-my_ptrace_child.patch ptrace_check_attach-remove-unneeded-signal-=-null-check.patch ptrace_stop-fix-the-race-with-ptrace-detachattach.patch wait_task_stopped-simplify-and-fix-races-with-sigcont-sigkill-untrace.patch do_wait-factor-out-retval-=-0-checks.patch ptrace_stop-fix-racy-nonstop_code-setting.patch wait_task_stopped-remove-unneeded-delay_group_leader-check.patch do_wait-cleanup-delay_group_leader-usage.patch do_wait-fix-security-checks.patch wait_task_continued-zombie-dont-use-task_pid_nr_ns-lockless.patch wait_task_zombie-remove-exit_state-exit_signal-checks-for-wnowait.patch - To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html