[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Qemu-devel] [PATCH 23/35] cpus: use broadcast on qemu_pause_cond

From: Michael Roth
Subject: [Qemu-devel] [PATCH 23/35] cpus: use broadcast on qemu_pause_cond
Date: Mon, 21 Mar 2016 12:28:21 -0500

From: "Dr. David Alan Gilbert" <address@hidden>

Jiri saw a hang on pause_all_vcpus called from postcopy_start,
where the cpus are all apparently stopped ('stopped' flag set)
but pause_all_vcpus is still stuck on a cond_wait on qemu_paused_cond.
We suspect this is happening if a qmp_stop is called at about the
same time as the postcopy code calls that pause_all_vcpus;
although they both should have the main lock held, Paolo spotted
the cond_wait unlocks the global lock so perhaps they both
could end up waiting at the same time?

Signed-off-by: Dr. David Alan Gilbert <address@hidden>
Reported-by: Jiri Denemark <address@hidden>
Message-Id: <address@hidden>
Cc: address@hidden
Signed-off-by: Paolo Bonzini <address@hidden>
(cherry picked from commit 96bce6831bd19b61e965384427741d805c7234c3)
Signed-off-by: Michael Roth <address@hidden>
 cpus.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/cpus.c b/cpus.c
index 43676fa..747f14d 100644
--- a/cpus.c
+++ b/cpus.c
@@ -986,7 +986,7 @@ static void qemu_wait_io_event_common(CPUState *cpu)
     if (cpu->stop) {
         cpu->stop = false;
         cpu->stopped = true;
-        qemu_cond_signal(&qemu_pause_cond);
+        qemu_cond_broadcast(&qemu_pause_cond);
     cpu->thread_kicked = false;
@@ -1387,7 +1387,7 @@ void cpu_stop_current(void)
         current_cpu->stop = false;
         current_cpu->stopped = true;
-        qemu_cond_signal(&qemu_pause_cond);
+        qemu_cond_broadcast(&qemu_pause_cond);

reply via email to

[Prev in Thread] Current Thread [Next in Thread]