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-rw-r--r--kernel/signal.c46
1 files changed, 29 insertions, 17 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index 8f0876f9f6dd..16a305295256 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1275,7 +1275,17 @@ struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
local_irq_restore(*flags);
break;
}
-
+ /*
+ * This sighand can be already freed and even reused, but
+ * we rely on SLAB_DESTROY_BY_RCU and sighand_ctor() which
+ * initializes ->siglock: this slab can't go away, it has
+ * the same object type, ->siglock can't be reinitialized.
+ *
+ * We need to ensure that tsk->sighand is still the same
+ * after we take the lock, we can race with de_thread() or
+ * __exit_signal(). In the latter case the next iteration
+ * must see ->sighand == NULL.
+ */
spin_lock(&sighand->siglock);
if (likely(sighand == tsk->sighand)) {
rcu_read_unlock();
@@ -1331,23 +1341,21 @@ int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
int error = -ESRCH;
struct task_struct *p;
- rcu_read_lock();
-retry:
- p = pid_task(pid, PIDTYPE_PID);
- if (p) {
- error = group_send_sig_info(sig, info, p);
- if (unlikely(error == -ESRCH))
- /*
- * The task was unhashed in between, try again.
- * If it is dead, pid_task() will return NULL,
- * if we race with de_thread() it will find the
- * new leader.
- */
- goto retry;
- }
- rcu_read_unlock();
+ for (;;) {
+ rcu_read_lock();
+ p = pid_task(pid, PIDTYPE_PID);
+ if (p)
+ error = group_send_sig_info(sig, info, p);
+ rcu_read_unlock();
+ if (likely(!p || error != -ESRCH))
+ return error;
- return error;
+ /*
+ * The task was unhashed in between, try again. If it
+ * is dead, pid_task() will return NULL, if we race with
+ * de_thread() it will find the new leader.
+ */
+ }
}
int kill_proc_info(int sig, struct siginfo *info, pid_t pid)
@@ -2748,6 +2756,10 @@ int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from)
if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)
err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
#endif
+#ifdef SEGV_BNDERR
+ err |= __put_user(from->si_lower, &to->si_lower);
+ err |= __put_user(from->si_upper, &to->si_upper);
+#endif
break;
case __SI_CHLD:
err |= __put_user(from->si_pid, &to->si_pid);