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[2001:470:27:1fa::2]) by smtp.gmail.com with ESMTPSA id s87-v6sm142360lfk.69.2018.04.02.10.14.21 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 02 Apr 2018 10:14:23 -0700 (PDT) From: Max Filippov To: qemu-devel@nongnu.org Date: Mon, 2 Apr 2018 10:13:49 -0700 Message-Id: <20180402171354.27706-4-jcmvbkbc@gmail.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20180402171354.27706-1-jcmvbkbc@gmail.com> References: <20180402171354.27706-1-jcmvbkbc@gmail.com> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2a00:1450:400c:c0c::242 Subject: [Qemu-devel] [PULL 3/8] linux-user: call cpu_copy under clone_lock X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , Riku Voipio , Laurent Vivier , Max Filippov Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP cpu_copy adds newly created CPU object to container/machine/unattached, but does it w/o proper locking. As a result when multiple threads create threads rapidly QEMU may abort with the following message: GLib-CRITICAL **: g_hash_table_iter_next: assertion 'ri->version == ri->hash_table->version' failed ERROR:qemu/qom/object.c:1663:object_get_canonical_path_component: code should not be reached E.g. this issue is observed when running glibc test nptl/tst-eintr1. Move cpu_copy invocation under clone_lock to fix that. Reviewed-by: Laurent Vivier Signed-off-by: Max Filippov --- linux-user/syscall.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 889abbda1e65..18ea79140f16 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -6346,6 +6346,10 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp, ts = g_new0(TaskState, 1); init_task_state(ts); + + /* Grab a mutex so that thread setup appears atomic. */ + pthread_mutex_lock(&clone_lock); + /* we create a new CPU instance. */ new_env = cpu_copy(env); /* Init regs that differ from the parent. */ @@ -6364,9 +6368,6 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp, cpu_set_tls (new_env, newtls); } - /* Grab a mutex so that thread setup appears atomic. */ - pthread_mutex_lock(&clone_lock); - memset(&info, 0, sizeof(info)); pthread_mutex_init(&info.mutex, NULL); pthread_mutex_lock(&info.mutex);