vhost: make sure used idx is seen before log in vhost_add_used_n()

[mirror_ubuntu-bionic-kernel.git] / kernel / signal.c

diff --git a/kernel/signal.c b/kernel/signal.c
index 9558664bd9ecd21d5cee8a504084b2ee4a2d0a50..3d876d4d98197ed6c69b0df4ef3f3ef69880f591 100644 (file)
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1003,7 +1003,7 @@ static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
 
        result = TRACE_SIGNAL_IGNORED;
        if (!prepare_signal(sig, t,
-                       from_ancestor_ns || (info == SEND_SIG_FORCED)))
+                       from_ancestor_ns || (info == SEND_SIG_PRIV) || (info == SEND_SIG_FORCED)))
                goto ret;
 
        pending = group ? &t->signal->shared_pending : &t->pending;
@@ -1828,14 +1828,27 @@ static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
                        return;
        }
 
+       set_special_state(TASK_TRACED);
+
        /*
         * We're committing to trapping.  TRACED should be visible before
         * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
         * Also, transition to TRACED and updates to ->jobctl should be
         * atomic with respect to siglock and should be done after the arch
         * hook as siglock is released and regrabbed across it.
+        *
+        *     TRACER                               TRACEE
+        *
+        *     ptrace_attach()
+        * [L]   wait_on_bit(JOBCTL_TRAPPING)   [S] set_special_state(TRACED)
+        *     do_wait()
+        *       set_current_state()                smp_wmb();
+        *       ptrace_do_wait()
+        *         wait_task_stopped()
+        *           task_stopped_code()
+        * [L]         task_is_traced()         [S] task_clear_jobctl_trapping();
         */
-       set_current_state(TASK_TRACED);
+       smp_wmb();
 
        current->last_siginfo = info;
        current->exit_code = exit_code;
@@ -2043,7 +2056,7 @@ static bool do_signal_stop(int signr)
                if (task_participate_group_stop(current))
                        notify = CLD_STOPPED;
 
-               __set_current_state(TASK_STOPPED);
+               set_special_state(TASK_STOPPED);
                spin_unlock_irq(&current->sighand->siglock);
 
                /*
@@ -2671,7 +2684,7 @@ COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
 }
 #endif
 
-enum siginfo_layout siginfo_layout(int sig, int si_code)
+enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
 {
        enum siginfo_layout layout = SIL_KILL;
        if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
@@ -3184,7 +3197,8 @@ int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
 }
 
 static int
-do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp)
+do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
+               size_t min_ss_size)
 {
        struct task_struct *t = current;
 
@@ -3214,7 +3228,7 @@ do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp)
                        ss_size = 0;
                        ss_sp = NULL;
                } else {
-                       if (unlikely(ss_size < MINSIGSTKSZ))
+                       if (unlikely(ss_size < min_ss_size))
                                return -ENOMEM;
                }
 
@@ -3232,7 +3246,8 @@ SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
        if (uss && copy_from_user(&new, uss, sizeof(stack_t)))
                return -EFAULT;
        err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL,
-                             current_user_stack_pointer());
+                             current_user_stack_pointer(),
+                             MINSIGSTKSZ);
        if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t)))
                err = -EFAULT;
        return err;
@@ -3243,7 +3258,8 @@ int restore_altstack(const stack_t __user *uss)
        stack_t new;
        if (copy_from_user(&new, uss, sizeof(stack_t)))
                return -EFAULT;
-       (void)do_sigaltstack(&new, NULL, current_user_stack_pointer());
+       (void)do_sigaltstack(&new, NULL, current_user_stack_pointer(),
+                            MINSIGSTKSZ);
        /* squash all but EFAULT for now */
        return 0;
 }
@@ -3278,7 +3294,8 @@ COMPAT_SYSCALL_DEFINE2(sigaltstack,
                uss.ss_size = uss32.ss_size;
        }
        ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss,
-                            compat_user_stack_pointer());
+                            compat_user_stack_pointer(),
+                            COMPAT_MINSIGSTKSZ);
        if (ret >= 0 && uoss_ptr)  {
                compat_stack_t old;
                memset(&old, 0, sizeof(old));