The patch titled
audit: use rcu for task lookup protection
has been added to the -mm tree. Its filename is
audit-use-rcu-for-task-lookup-protection.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: audit: use rcu for task lookup protection
From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Protect the task lookups in audit_receive_msg() with rcu_read_lock()
instead of tasklist_lock and use lock/unlock_sighand to protect against
the exit race.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Eric Paris <eparis@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/audit.c | 30 ++++++++++++++----------------
1 file changed, 14 insertions(+), 16 deletions(-)
diff -puN kernel/audit.c~audit-use-rcu-for-task-lookup-protection kernel/audit.c
--- a/kernel/audit.c~audit-use-rcu-for-task-lookup-protection
+++ a/kernel/audit.c
@@ -873,17 +873,16 @@ static int audit_receive_msg(struct sk_b
case AUDIT_TTY_GET: {
struct audit_tty_status s;
struct task_struct *tsk;
+ unsigned long flags;
- read_lock(&tasklist_lock);
+ rcu_read_lock();
tsk = find_task_by_vpid(pid);
- if (!tsk)
- err = -ESRCH;
- else {
- spin_lock_irq(&tsk->sighand->siglock);
+ if (tsk && lock_task_sighand(tsk, &flags)) {
s.enabled = tsk->signal->audit_tty != 0;
- spin_unlock_irq(&tsk->sighand->siglock);
- }
- read_unlock(&tasklist_lock);
+ unlock_task_sighand(tsk, &flags);
+ } else
+ err = -ESRCH;
+ rcu_read_unlock();
if (!err)
audit_send_reply(NETLINK_CB(skb).pid, seq,
@@ -893,22 +892,21 @@ static int audit_receive_msg(struct sk_b
case AUDIT_TTY_SET: {
struct audit_tty_status *s;
struct task_struct *tsk;
+ unsigned long flags;
if (nlh->nlmsg_len < sizeof(struct audit_tty_status))
return -EINVAL;
s = data;
if (s->enabled != 0 && s->enabled != 1)
return -EINVAL;
- read_lock(&tasklist_lock);
+ rcu_read_lock();
tsk = find_task_by_vpid(pid);
- if (!tsk)
- err = -ESRCH;
- else {
- spin_lock_irq(&tsk->sighand->siglock);
+ if (tsk && lock_task_sighand(tsk, &flags)) {
tsk->signal->audit_tty = s->enabled != 0;
- spin_unlock_irq(&tsk->sighand->siglock);
- }
- read_unlock(&tasklist_lock);
+ unlock_task_sighand(tsk, &flags);
+ } else
+ err = -ESRCH;
+ rcu_read_unlock();
break;
}
default:
_
Patches currently in -mm which might be from tglx@xxxxxxxxxxxxx are
linux-next.patch
audit-call-tty_audit_push_task-outside-preempt-disabled.patch
audit-do-not-send-uninitialized-data-for-audit_tty_get.patch
audit-use-rcu-for-task-lookup-protection.patch
time-compensate-for-rounding-on-odd-frequency-clocksources.patch
x86-enable-arch_dma_addr_t_64bit-with-x86_64-highmem64g.patch
hpet-fix-unwanted-interrupt-due-to-stale-irq-status-bit.patch
hpet-factor-timer-allocate-from-open.patch
timer_list-remove-alignment-padding-on-64-bit-when-config_timer_stats.patch
timer-initialize-the-field-slack-of-timer_list.patch
kernel-time-use-array_size-macro-in-timecomparec.patch
sched-make-sched_param-argument-static-variables-in-some-sched_setscheduler-caller.patch
kernelh-add-minmax3-macros.patch
kernelh-add-minmax3-macros-fix.patch
replace-nested-max-min-macros-with-maxmin3-macro.patch
add-the-common-dma_addr_t-typedef-to-include-linux-typesh.patch
select-rename-estimate_accuracy-to-select_estimate_accuracy.patch
epoll-make-epoll_wait-use-the-hrtimer-range-feature.patch
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