* [Qemu-devel] [PULL 1/2] fsdev-proxy-helper: avoid TOC/TOU race
2015-11-30 16:11 [Qemu-devel] [PULL 0/2] virtio-9p fixes for 2.5 Greg Kurz
@ 2015-11-30 16:11 ` Greg Kurz
2015-11-30 16:11 ` [Qemu-devel] [PULL 2/2] virtio-9p: use QEMU thread pool Greg Kurz
2015-12-01 16:30 ` [Qemu-devel] [PULL 0/2] virtio-9p fixes for 2.5 Peter Maydell
2 siblings, 0 replies; 5+ messages in thread
From: Greg Kurz @ 2015-11-30 16:11 UTC (permalink / raw)
To: qemu-devel; +Cc: Peter Maydell, Greg Kurz, Aneesh Kumar K.V, Paolo Bonzini
From: Paolo Bonzini <pbonzini@redhat.com>
There is a minor time of check/time of use race between statfs and chroot.
It can be fixed easily by stat-ing the root after it has been changed.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
---
fsdev/virtfs-proxy-helper.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/fsdev/virtfs-proxy-helper.c b/fsdev/virtfs-proxy-helper.c
index 9097d15c989c..ad1da0d6f530 100644
--- a/fsdev/virtfs-proxy-helper.c
+++ b/fsdev/virtfs-proxy-helper.c
@@ -1128,10 +1128,19 @@ int main(int argc, char **argv)
}
}
+ if (chdir("/") < 0) {
+ do_perror("chdir");
+ goto error;
+ }
+ if (chroot(rpath) < 0) {
+ do_perror("chroot");
+ goto error;
+ }
+
get_version = false;
#ifdef FS_IOC_GETVERSION
/* check whether underlying FS support IOC_GETVERSION */
- retval = statfs(rpath, &st_fs);
+ retval = statfs("/", &st_fs);
if (!retval) {
switch (st_fs.f_type) {
case EXT2_SUPER_MAGIC:
@@ -1144,16 +1153,7 @@ int main(int argc, char **argv)
}
#endif
- if (chdir("/") < 0) {
- do_perror("chdir");
- goto error;
- }
- if (chroot(rpath) < 0) {
- do_perror("chroot");
- goto error;
- }
umask(0);
-
if (init_capabilities() < 0) {
goto error;
}
--
2.4.3
^ permalink raw reply related [flat|nested] 5+ messages in thread* [Qemu-devel] [PULL 2/2] virtio-9p: use QEMU thread pool
2015-11-30 16:11 [Qemu-devel] [PULL 0/2] virtio-9p fixes for 2.5 Greg Kurz
2015-11-30 16:11 ` [Qemu-devel] [PULL 1/2] fsdev-proxy-helper: avoid TOC/TOU race Greg Kurz
@ 2015-11-30 16:11 ` Greg Kurz
2015-12-01 16:30 ` [Qemu-devel] [PULL 0/2] virtio-9p fixes for 2.5 Peter Maydell
2 siblings, 0 replies; 5+ messages in thread
From: Greg Kurz @ 2015-11-30 16:11 UTC (permalink / raw)
To: qemu-devel; +Cc: Peter Maydell, Greg Kurz, Aneesh Kumar K.V, Paolo Bonzini
From: Paolo Bonzini <pbonzini@redhat.com>
The QEMU thread pool already has a mechanism to invoke callbacks in the main
thread. It does not need an EventNotifier and it is more efficient too.
Use it instead of GAsyncQueue + GThreadPool + glue.
As a side effect, it silences Coverity's complaint about an unchecked
return value for event_notifier_init.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
(removed no more needed #include <glib.h> from virtio-9p-coth.h)
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
---
hw/9pfs/virtio-9p-coth.c | 69 ++++++++++------------------------------------
hw/9pfs/virtio-9p-coth.h | 10 +------
hw/9pfs/virtio-9p-device.c | 4 ---
3 files changed, 15 insertions(+), 68 deletions(-)
diff --git a/hw/9pfs/virtio-9p-coth.c b/hw/9pfs/virtio-9p-coth.c
index 5057f8d220df..fb6e8f80e0f4 100644
--- a/hw/9pfs/virtio-9p-coth.c
+++ b/hw/9pfs/virtio-9p-coth.c
@@ -12,71 +12,30 @@
*
*/
-#include "fsdev/qemu-fsdev.h"
-#include "qemu/thread.h"
-#include "qemu/event_notifier.h"
+#include "qemu-common.h"
+#include "block/thread-pool.h"
#include "qemu/coroutine.h"
+#include "qemu/main-loop.h"
#include "virtio-9p-coth.h"
-/* v9fs glib thread pool */
-static V9fsThPool v9fs_pool;
-
-void co_run_in_worker_bh(void *opaque)
+/* Called from QEMU I/O thread. */
+static void coroutine_enter_cb(void *opaque, int ret)
{
Coroutine *co = opaque;
- g_thread_pool_push(v9fs_pool.pool, co, NULL);
-}
-
-static void v9fs_qemu_process_req_done(EventNotifier *e)
-{
- Coroutine *co;
-
- event_notifier_test_and_clear(e);
-
- while ((co = g_async_queue_try_pop(v9fs_pool.completed)) != NULL) {
- qemu_coroutine_enter(co, NULL);
- }
+ qemu_coroutine_enter(co, NULL);
}
-static void v9fs_thread_routine(gpointer data, gpointer user_data)
+/* Called from worker thread. */
+static int coroutine_enter_func(void *arg)
{
- Coroutine *co = data;
-
+ Coroutine *co = arg;
qemu_coroutine_enter(co, NULL);
-
- g_async_queue_push(v9fs_pool.completed, co);
-
- event_notifier_set(&v9fs_pool.e);
+ return 0;
}
-int v9fs_init_worker_threads(void)
+void co_run_in_worker_bh(void *opaque)
{
- int ret = 0;
- V9fsThPool *p = &v9fs_pool;
- sigset_t set, oldset;
-
- sigfillset(&set);
- /* Leave signal handling to the iothread. */
- pthread_sigmask(SIG_SETMASK, &set, &oldset);
-
- p->pool = g_thread_pool_new(v9fs_thread_routine, p, -1, FALSE, NULL);
- if (!p->pool) {
- ret = -1;
- goto err_out;
- }
- p->completed = g_async_queue_new();
- if (!p->completed) {
- /*
- * We are going to terminate.
- * So don't worry about cleanup
- */
- ret = -1;
- goto err_out;
- }
- event_notifier_init(&p->e, 0);
-
- event_notifier_set_handler(&p->e, v9fs_qemu_process_req_done);
-err_out:
- pthread_sigmask(SIG_SETMASK, &oldset, NULL);
- return ret;
+ Coroutine *co = opaque;
+ thread_pool_submit_aio(qemu_get_aio_context()->thread_pool,
+ coroutine_enter_func, co, coroutine_enter_cb, co);
}
diff --git a/hw/9pfs/virtio-9p-coth.h b/hw/9pfs/virtio-9p-coth.h
index 0fbe49a94615..4ac1aaf90292 100644
--- a/hw/9pfs/virtio-9p-coth.h
+++ b/hw/9pfs/virtio-9p-coth.h
@@ -18,14 +18,6 @@
#include "qemu/thread.h"
#include "qemu/coroutine.h"
#include "virtio-9p.h"
-#include <glib.h>
-
-typedef struct V9fsThPool {
- EventNotifier e;
-
- GThreadPool *pool;
- GAsyncQueue *completed;
-} V9fsThPool;
/*
* we want to use bottom half because we want to make sure the below
@@ -45,7 +37,7 @@ typedef struct V9fsThPool {
qemu_bh_schedule(co_bh); \
/* \
* yield in qemu thread and re-enter back \
- * in glib worker thread \
+ * in worker thread \
*/ \
qemu_coroutine_yield(); \
qemu_bh_delete(co_bh); \
diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c
index e3abcfaffb2a..944b5f5e9fcc 100644
--- a/hw/9pfs/virtio-9p-device.c
+++ b/hw/9pfs/virtio-9p-device.c
@@ -116,10 +116,6 @@ static void virtio_9p_device_realize(DeviceState *dev, Error **errp)
" and export path:%s", s->fsconf.fsdev_id, s->ctx.fs_root);
goto out;
}
- if (v9fs_init_worker_threads() < 0) {
- error_setg(errp, "worker thread initialization failed");
- goto out;
- }
/*
* Check details of export path, We need to use fs driver
--
2.4.3
^ permalink raw reply related [flat|nested] 5+ messages in thread