diff options
| -rw-r--r-- | kernel/signal.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/kernel/signal.c b/kernel/signal.c index b3dedf1f932..13371d17358 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2219,6 +2219,7 @@ static int do_tkill(int tgid, int pid, int sig) int error; struct siginfo info; struct task_struct *p; + unsigned long flags; error = -ESRCH; info.si_signo = sig; @@ -2227,21 +2228,24 @@ static int do_tkill(int tgid, int pid, int sig) info.si_pid = task_tgid_vnr(current); info.si_uid = current->uid; - read_lock(&tasklist_lock); + rcu_read_lock(); p = find_task_by_vpid(pid); if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { error = check_kill_permission(sig, &info, p); /* * The null signal is a permissions and process existence * probe. No signal is actually delivered. + * + * If lock_task_sighand() fails we pretend the task dies + * after receiving the signal. The window is tiny, and the + * signal is private anyway. */ - if (!error && sig && p->sighand) { - spin_lock_irq(&p->sighand->siglock); + if (!error && sig && lock_task_sighand(p, &flags)) { error = specific_send_sig_info(sig, &info, p); - spin_unlock_irq(&p->sighand->siglock); + unlock_task_sighand(p, &flags); } } - read_unlock(&tasklist_lock); + rcu_read_unlock(); return error; } |