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[PULL,44/44] linux-user: In fork_end(), remove correct CPUs from CPU list

Message ID 014628a705bdaf31c09915c29e61f4088956564d.1465392531.git.riku.voipio@linaro.org
State Accepted
Commit 014628a705bdaf31c09915c29e61f4088956564d
Headers show

Commit Message

Riku Voipio June 8, 2016, 1:30 p.m. UTC 
From: Peter Maydell <peter.maydell@linaro.org>


In fork_end(), we must fix the list of current CPUs to match the fact
that the child of the fork has only one thread. Unfortunately we were
removing the wrong CPUs from the list, which meant that if the child
subsequently did an exclusive operation it would deadlock in
start_exclusive() waiting for a sibling CPU which didn't exist.

In particular this could cause hangs doing git submodule init
operations, as reported in https://bugs.launchpad.net/qemu/+bug/955379
comment #47.

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

Signed-off-by: Riku Voipio <riku.voipio@linaro.org>

---
 linux-user/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

-- 
2.1.4
diff mbox

Patch

diff --git a/linux-user/main.c b/linux-user/main.c
index b6da0ba..150a356 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -130,7 +130,7 @@  void fork_end(int child)
            Discard information about the parent threads.  */
         CPU_FOREACH_SAFE(cpu, next_cpu) {
             if (cpu != thread_cpu) {
-                QTAILQ_REMOVE(&cpus, thread_cpu, node);
+                QTAILQ_REMOVE(&cpus, cpu, node);
             }
         }
         pending_cpus = 0;