The patch titled
wait_task_stopped(): don't use task_pid_nr_ns() lockless
has been added to the -mm tree. Its filename is
wait_task_stopped-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_stopped(): don't use task_pid_nr_ns() lockless
From: Oleg Nesterov <oleg@xxxxxxxxxx>
wait_task_stopped(WNOWAIT) does task_pid_nr_ns() without tasklist/rcu lock,
we can read an already freed memory. Use the cached pid_t value.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Looks-good-to: Roland McGrath <roland@xxxxxxxxxx>
Acked-by: Pavel Emelyanov <xemul@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/exit.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff -puN kernel/exit.c~wait_task_stopped-dont-use-task_pid_nr_ns-lockless kernel/exit.c
--- a/kernel/exit.c~wait_task_stopped-dont-use-task_pid_nr_ns-lockless
+++ a/kernel/exit.c
@@ -1357,7 +1357,7 @@ static int wait_task_stopped(struct task
int __user *stat_addr, struct rusage __user *ru)
{
int retval, exit_code;
- struct pid_namespace *ns;
+ pid_t pid;
if (!p->exit_code)
return 0;
@@ -1376,12 +1376,11 @@ static int wait_task_stopped(struct task
* keep holding onto the tasklist_lock while we call getrusage and
* possibly take page faults for user memory.
*/
- ns = current->nsproxy->pid_ns;
+ pid = task_pid_nr_ns(p, current->nsproxy->pid_ns);
get_task_struct(p);
read_unlock(&tasklist_lock);
if (unlikely(noreap)) {
- pid_t pid = task_pid_nr_ns(p, ns);
uid_t uid = p->uid;
int why = (p->ptrace & PT_PTRACED) ? CLD_TRAPPED : CLD_STOPPED;
@@ -1451,11 +1450,11 @@ bail_ref:
if (!retval && infop)
retval = put_user(exit_code, &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;
put_task_struct(p);
BUG_ON(!retval);
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
wait_task_stopped-dont-use-task_pid_nr_ns-lockless.patch
add-task_wakekill.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
