diff options
author | Aníbal Limón <anibal.limon@linux.intel.com> | 2015-09-03 15:48:33 -0500 |
---|---|---|
committer | Michael Roth <mdroth@linux.vnet.ibm.com> | 2015-10-20 20:00:17 -0500 |
commit | d077545dfef3d59f0286e0cb28cdb1c6d0570c22 (patch) | |
tree | da64269d5935da7ca03edeb955ab8091d7954f24 | |
parent | f6737604da3b44322a91ebaa4b184aa519bbb66a (diff) | |
download | qemu-d077545dfef3d59f0286e0cb28cdb1c6d0570c22.tar.gz |
cpus.c: qemu_mutex_lock_iothread fix race condition at cpu thread init
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
Cc: qemu-stable@nongnu.org
Signed-off-by: Aníbal Limón <anibal.limon@linux.intel.com>
Message-Id: <1441313313-3040-1-git-send-email-anibal.limon@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 46036b2462c7ff56c0af6466ea6b9248197a38a8)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
-rw-r--r-- | cpus.c | 2 |
1 files changed, 1 insertions, 1 deletions
@@ -1166,7 +1166,7 @@ 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 { |