| Upstream-Status: Submitted |
| |
| From f354b9333408d411854af058cc44cceda60b4473 Mon Sep 17 00:00:00 2001 |
| From: =?UTF-8?q?An=C3=ADbal=20Lim=C3=B3n?= <anibal.limon@linux.intel.com> |
| Date: Thu, 3 Sep 2015 14:07:34 -0500 |
| Subject: [PATCH] cpus.c: qemu_mutex_lock_iothread fix race condition at cpu |
| thread init |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=UTF-8 |
| Content-Transfer-Encoding: 8bit |
| |
| When QEMU starts the RCU thread executes qemu_mutex_lock_thread |
| causing error "qemu:qemu_cpu_kick_thread: No such process" and exits. |
| |
| This isn't occur frequently but in glibc the thread id can exist and |
| this not guarantee that the thread is on active/running state. If is |
| inserted a sleep(1) after newthread assignment [1] the issue appears. |
| |
| So not make assumption that thread exist if first_cpu->thread is set |
| then change the validation of cpu to created that is set into cpu |
| threads (kvm, tcg, dummy). |
| |
| [1] https://sourceware.org/git/?p=glibc.git;a=blob;f=nptl/pthread_create.c;h=d10f4ea8004e1d8f3a268b95cc0f8d93b8d89867;hb=HEAD#l621 |
| |
| Signed-off-by: Aníbal Limón <anibal.limon@linux.intel.com> |
| --- |
| cpus.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| diff --git a/cpus.c b/cpus.c |
| index 7e4786e..05e5400 100644 |
| --- a/cpus.c |
| +++ b/cpus.c |
| @@ -1171,7 +1171,7 @@ void qemu_mutex_lock_iothread(void) |
| * TCG code execution. |
| */ |
| if (!tcg_enabled() || qemu_in_vcpu_thread() || |
| - !first_cpu || !first_cpu->thread) { |
| + !first_cpu || !first_cpu->created) { |
| qemu_mutex_lock(&qemu_global_mutex); |
| atomic_dec(&iothread_requesting_mutex); |
| } else { |
| -- |
| 1.9.1 |
| |