diff mbox series

[PULL,v2,3/8] linux-user: Always exit from exclusive state in fork_end()

Message ID 20230222020023.904232-4-richard.henderson@linaro.org
State Accepted
Commit 7de0816f699553514016f52a76e26d1c2ae14034
Headers show
Series [PULL,v2,1/8] accel/tcg: Allow the second page of an instruction to be MMIO | expand

Commit Message

Richard Henderson Feb. 22, 2023, 2 a.m. UTC 
From: Ilya Leoshkevich <iii@linux.ibm.com>

fork()ed processes currently start with
current_cpu->in_exclusive_context set, which is, strictly speaking, not
correct, but does not cause problems (even assertion failures).

With one of the next patches, the code begins to rely on this value, so
fix it by always calling end_exclusive() in fork_end().

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-Id: <20230214140829.45392-2-iii@linux.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/main.c    | 10 ++++++----
 linux-user/syscall.c |  1 +
 2 files changed, 7 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/linux-user/main.c b/linux-user/main.c
index 4290651c3c..4ff30ff980 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -161,13 +161,15 @@  void fork_end(int child)
         }
         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 {
         cpu_list_unlock();
-        end_exclusive();
     }
+    /*
+     * qemu_init_cpu_list() reinitialized the child exclusive state, but we
+     * also need to keep current_cpu consistent, so call end_exclusive() for
+     * both child and parent.
+     */
+    end_exclusive();
 }
 
 __thread CPUState *thread_cpu;
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 1e868e9b0e..a6c426d73c 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -6752,6 +6752,7 @@  static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp,
             cpu_clone_regs_parent(env, flags);
             fork_end(0);
         }
+        g_assert(!cpu_in_exclusive_context(cpu));
     }
     return ret;
 }