Merge remote-tracking branch 'remotes/vivier2/tags/linux-user-for-2.12-pull-request' into staging

# gpg: Signature made Tue 23 Jan 2018 14:47:41 GMT
# gpg:                using RSA key 0xF30C38BD3F2FBE3C
# gpg: Good signature from "Laurent Vivier <lvivier@redhat.com>"
# gpg:                 aka "Laurent Vivier <laurent@vivier.eu>"
# gpg:                 aka "Laurent Vivier (Red Hat) <lvivier@redhat.com>"
# Primary key fingerprint: CD2F 75DD C8E3 A4DC 2E4F  5173 F30C 38BD 3F2F BE3C

* remotes/vivier2/tags/linux-user-for-2.12-pull-request:
  linux-user: implement renameat2
  page_unprotect(): handle calls to pages that are PAGE_WRITE
  linux-user: Propagate siginfo_t through to handle_cpu_signal()
  linux-user: remove nmi.c and fw-path-provider.c
  linux-user: Add getcpu() support
  linux-user: Add AT_SECURE auxval
  linux-user: Fix sched_get/setaffinity conversion
  linux-user/mmap.c: Avoid choosing NULL as start address
  linux-user: Translate flags argument to dup3 syscall
  linux-user: Don't use CMSG_ALIGN(sizeof struct cmsghdr)
  linux-user: Fix length calculations in host_to_target_cmsg()
  linux-user: wrap fork() in a start/end exclusive section
  linux-user: Fix locking order in fork_start()

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 7 insertions, 2 deletions

diff --git a/linux-user/main.c b/linux-user/main.c
index 450eb3ce65..2140465709 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -127,9 +127,10 @@ int cpu_get_pic_interrupt(CPUX86State *env)
 /* Make sure everything is in a consistent state for calling fork().  */
 void fork_start(void)
 {
-    cpu_list_lock();
-    qemu_mutex_lock(&tb_ctx.tb_lock);
+    start_exclusive();
     mmap_fork_start();
+    qemu_mutex_lock(&tb_ctx.tb_lock);
+    cpu_list_lock();
 }
 
 void fork_end(int child)
@@ -147,9 +148,13 @@ void fork_end(int child)
         qemu_mutex_init(&tb_ctx.tb_lock);
         qemu_init_cpu_list();
         gdbserver_fork(thread_cpu);
+        /* qemu_init_cpu_list() takes care of reinitializing the
+         * exclusive state, so we don't need to end_exclusive() here.
+         */
     } else {
         qemu_mutex_unlock(&tb_ctx.tb_lock);
         cpu_list_unlock();
+        end_exclusive();
     }
 }