doc: add item for "-M enforce-config-section"

[qemu.git] / user-exec.c

diff --git a/user-exec.c b/user-exec.c
index 95f9f97c5c82480d9730f294001821589c591b17..a8f95fa1e1432046ce35f9ab381fbfeb38acda41 100644 (file)
--- a/user-exec.c
+++ b/user-exec.c
@@ -57,10 +57,23 @@ static void cpu_exit_tb_from_sighandler(CPUState *cpu, sigset_t *old_set)
 static inline int handle_cpu_signal(uintptr_t pc, unsigned long address,
                                     int is_write, sigset_t *old_set)
 {
-    CPUState *cpu;
+    CPUState *cpu = current_cpu;
     CPUClass *cc;
     int ret;
 
+    /* For synchronous signals we expect to be coming from the vCPU
+     * thread (so current_cpu should be valid) and either from running
+     * code or during translation which can fault as we cross pages.
+     *
+     * If neither is true then something has gone wrong and we should
+     * abort rather than try and restart the vCPU execution.
+     */
+    if (!cpu || !cpu->running) {
+        printf("qemu:%s received signal outside vCPU context @ pc=0x%"
+               PRIxPTR "\n",  __func__, pc);
+        abort();
+    }
+
 #if defined(DEBUG_SIGNAL)
     printf("qemu: SIGSEGV pc=0x%08lx address=%08lx w=%d oldset=0x%08lx\n",
            pc, address, is_write, *(unsigned long *)old_set);
@@ -83,7 +96,7 @@ static inline int handle_cpu_signal(uintptr_t pc, unsigned long address,
              * currently executing TB was modified and must be exited
              * immediately.
              */
-            cpu_exit_tb_from_sighandler(current_cpu, old_set);
+            cpu_exit_tb_from_sighandler(cpu, old_set);
             g_assert_not_reached();
         default:
             g_assert_not_reached();
@@ -94,7 +107,6 @@ static inline int handle_cpu_signal(uintptr_t pc, unsigned long address,
        are still valid segv ones */
     address = h2g_nocheck(address);
 
-    cpu = current_cpu;
     cc = CPU_GET_CLASS(cpu);
     /* see if it is an MMU fault */
     g_assert(cc->handle_mmu_fault);
@@ -105,8 +117,11 @@ static inline int handle_cpu_signal(uintptr_t pc, unsigned long address,
     if (ret == 0) {
         return 1; /* the MMU fault was handled without causing real CPU fault */
     }
-    /* now we have a real cpu fault */
-    cpu_restore_state(cpu, pc);
+
+    /* Now we have a real cpu fault.  Since this is the exact location of
+     * the exception, we must undo the adjustment done by cpu_restore_state
+     * for handling call return addresses.  */
+    cpu_restore_state(cpu, pc + GETPC_ADJ);
 
     sigprocmask(SIG_SETMASK, old_set, NULL);
     cpu_loop_exit(cpu);