[PATCH] lock group_send_sig_info() properly

  - a read_lock(&tasklist_lock) is missing around the group_send_sig_info()
    in send_sig_info().

diff --git a/kernel/signal.c b/kernel/signal.c
index 3ebef47892239da2789b723a04809f625b0f68cb..9dc47e8a804aeaddc89fdbfb3592a77a38df0f71 100644 (file)
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -944,8 +944,10 @@ void zap_other_threads(struct task_struct *p)
        }
 }
 
-int
-group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
+/*
+ * Must be called with the tasklist_lock held for reading!
+ */
+int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
 {
        unsigned long flags;
        int ret;
@@ -1083,17 +1085,19 @@ static int kill_something_info(int sig, struct siginfo *info, int pid)
 int
 send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
 {
+       int ret;
+
        /* XXX should nix these interfaces and update the kernel */
-       if (T(sig, SIG_KERNEL_BROADCAST_MASK))
-               /* XXX do callers really always hold the tasklist_lock?? */
-               return group_send_sig_info(sig, info, p);
-       else {
-               int error;
+       if (T(sig, SIG_KERNEL_BROADCAST_MASK)) {
+               read_lock(&tasklist_lock);
+               ret = group_send_sig_info(sig, info, p);
+               read_unlock(&tasklist_lock);
+       } else {
                spin_lock_irq(&p->sighand->siglock);
-               error = specific_send_sig_info(sig, info, p);
+               ret = specific_send_sig_info(sig, info, p);
                spin_unlock_irq(&p->sighand->siglock);
-               return error;
        }
+       return ret;
 }
 
 int