async: aio_context_new(): Handle event_notifier_init failure
On a system with a low limit of open files the initialization
of the event notifier could fail and QEMU exits without printing any
error information to the user.
The problem can be easily reproduced by enforcing a low limit of open
files and start QEMU with enough I/O threads to hit this limit.
The same problem raises, without the creation of I/O threads, while
QEMU initializes the main event loop by enforcing an even lower limit of
open files.
This commit adds an error message on failure:
# qemu [...] -object iothread,id=iothread0 -object iothread,id=iothread1
qemu: Failed to initialize event notifier: Too many open files in system
Signed-off-by: Chrysostomos Nanakos <cnanakos@grnet.gr>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/async.c b/async.c
index a99e7f6..6e1b282 100644
--- a/async.c
+++ b/async.c
@@ -289,18 +289,24 @@
aio_notify(opaque);
}
-AioContext *aio_context_new(void)
+AioContext *aio_context_new(Error **errp)
{
+ int ret;
AioContext *ctx;
ctx = (AioContext *) g_source_new(&aio_source_funcs, sizeof(AioContext));
+ ret = event_notifier_init(&ctx->notifier, false);
+ if (ret < 0) {
+ g_source_destroy(&ctx->source);
+ error_setg_errno(errp, -ret, "Failed to initialize event notifier");
+ return NULL;
+ }
+ aio_set_event_notifier(ctx, &ctx->notifier,
+ (EventNotifierHandler *)
+ event_notifier_test_and_clear);
ctx->pollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD));
ctx->thread_pool = NULL;
qemu_mutex_init(&ctx->bh_lock);
rfifolock_init(&ctx->lock, aio_rfifolock_cb, ctx);
- event_notifier_init(&ctx->notifier, false);
- aio_set_event_notifier(ctx, &ctx->notifier,
- (EventNotifierHandler *)
- event_notifier_test_and_clear);
timerlistgroup_init(&ctx->tlg, aio_timerlist_notify, ctx);
return ctx;
diff --git a/include/block/aio.h b/include/block/aio.h
index 67a75dd..1562721 100644
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -102,7 +102,7 @@
* They also provide bottom halves, a service to execute a piece of code
* as soon as possible.
*/
-AioContext *aio_context_new(void);
+AioContext *aio_context_new(Error **errp);
/**
* aio_context_ref:
diff --git a/include/qemu/main-loop.h b/include/qemu/main-loop.h
index 6f0200a..62c68c0 100644
--- a/include/qemu/main-loop.h
+++ b/include/qemu/main-loop.h
@@ -42,7 +42,7 @@
*
* In the case of QEMU tools, this will also start/initialize timers.
*/
-int qemu_init_main_loop(void);
+int qemu_init_main_loop(Error **errp);
/**
* main_loop_wait: Run one iteration of the main loop.
diff --git a/iothread.c b/iothread.c
index d9403cf..342a23f 100644
--- a/iothread.c
+++ b/iothread.c
@@ -17,6 +17,7 @@
#include "block/aio.h"
#include "sysemu/iothread.h"
#include "qmp-commands.h"
+#include "qemu/error-report.h"
#define IOTHREADS_PATH "/objects"
@@ -53,6 +54,9 @@
{
IOThread *iothread = IOTHREAD(obj);
+ if (!iothread->ctx) {
+ return;
+ }
iothread->stopping = true;
aio_notify(iothread->ctx);
qemu_thread_join(&iothread->thread);
@@ -63,11 +67,16 @@
static void iothread_complete(UserCreatable *obj, Error **errp)
{
+ Error *local_error = NULL;
IOThread *iothread = IOTHREAD(obj);
iothread->stopping = false;
- iothread->ctx = aio_context_new();
iothread->thread_id = -1;
+ iothread->ctx = aio_context_new(&local_error);
+ if (!iothread->ctx) {
+ error_propagate(errp, local_error);
+ return;
+ }
qemu_mutex_init(&iothread->init_done_lock);
qemu_cond_init(&iothread->init_done_cond);
diff --git a/main-loop.c b/main-loop.c
index 3cc79f8..53393a4 100644
--- a/main-loop.c
+++ b/main-loop.c
@@ -126,10 +126,11 @@
static GArray *gpollfds;
-int qemu_init_main_loop(void)
+int qemu_init_main_loop(Error **errp)
{
int ret;
GSource *src;
+ Error *local_error = NULL;
init_clocks();
@@ -138,8 +139,12 @@
return ret;
}
+ qemu_aio_context = aio_context_new(&local_error);
+ if (!qemu_aio_context) {
+ error_propagate(errp, local_error);
+ return -EMFILE;
+ }
gpollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD));
- qemu_aio_context = aio_context_new();
src = aio_get_g_source(qemu_aio_context);
g_source_attach(src, NULL);
g_source_unref(src);
diff --git a/qemu-img.c b/qemu-img.c
index 91d1ac3..dbf0904 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -2879,6 +2879,7 @@
{
const img_cmd_t *cmd;
const char *cmdname;
+ Error *local_error = NULL;
int c;
static const struct option long_options[] = {
{"help", no_argument, 0, 'h'},
@@ -2893,7 +2894,12 @@
error_set_progname(argv[0]);
qemu_init_exec_dir(argv[0]);
- qemu_init_main_loop();
+ if (qemu_init_main_loop(&local_error)) {
+ error_report("%s", error_get_pretty(local_error));
+ error_free(local_error);
+ exit(EXIT_FAILURE);
+ }
+
bdrv_init();
if (argc < 2) {
error_exit("Not enough arguments");
diff --git a/qemu-io.c b/qemu-io.c
index d2ab694..66cf3ef 100644
--- a/qemu-io.c
+++ b/qemu-io.c
@@ -379,6 +379,7 @@
int c;
int opt_index = 0;
int flags = BDRV_O_UNMAP;
+ Error *local_error = NULL;
#ifdef CONFIG_POSIX
signal(SIGPIPE, SIG_IGN);
@@ -444,7 +445,11 @@
exit(1);
}
- qemu_init_main_loop();
+ if (qemu_init_main_loop(&local_error)) {
+ error_report("%s", error_get_pretty(local_error));
+ error_free(local_error);
+ exit(1);
+ }
bdrv_init();
/* initialize commands */
diff --git a/qemu-nbd.c b/qemu-nbd.c
index 9bc152e..de9963f 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -674,7 +674,11 @@
snprintf(sockpath, 128, SOCKET_PATH, basename(device));
}
- qemu_init_main_loop();
+ if (qemu_init_main_loop(&local_err)) {
+ error_report("%s", error_get_pretty(local_err));
+ error_free(local_err);
+ exit(EXIT_FAILURE);
+ }
bdrv_init();
atexit(bdrv_close_all);
diff --git a/tests/test-aio.c b/tests/test-aio.c
index c6a8713..a7cb5c9 100644
--- a/tests/test-aio.c
+++ b/tests/test-aio.c
@@ -14,6 +14,7 @@
#include "block/aio.h"
#include "qemu/timer.h"
#include "qemu/sockets.h"
+#include "qemu/error-report.h"
static AioContext *ctx;
@@ -810,11 +811,18 @@
int main(int argc, char **argv)
{
+ Error *local_error = NULL;
GSource *src;
init_clocks();
- ctx = aio_context_new();
+ ctx = aio_context_new(&local_error);
+ if (!ctx) {
+ error_report("Failed to create AIO Context: '%s'",
+ error_get_pretty(local_error));
+ error_free(local_error);
+ exit(1);
+ }
src = aio_get_g_source(ctx);
g_source_attach(src, NULL);
g_source_unref(src);
diff --git a/tests/test-thread-pool.c b/tests/test-thread-pool.c
index ed2b25b..8c4d68b 100644
--- a/tests/test-thread-pool.c
+++ b/tests/test-thread-pool.c
@@ -4,6 +4,7 @@
#include "block/thread-pool.h"
#include "block/block.h"
#include "qemu/timer.h"
+#include "qemu/error-report.h"
static AioContext *ctx;
static ThreadPool *pool;
@@ -222,10 +223,17 @@
int main(int argc, char **argv)
{
int ret;
+ Error *local_error = NULL;
init_clocks();
- ctx = aio_context_new();
+ ctx = aio_context_new(&local_error);
+ if (!ctx) {
+ error_report("Failed to create AIO Context: '%s'",
+ error_get_pretty(local_error));
+ error_free(local_error);
+ exit(1);
+ }
pool = aio_get_thread_pool(ctx);
g_test_init(&argc, &argv, NULL);
diff --git a/tests/test-throttle.c b/tests/test-throttle.c
index 000ae31..d8ba415 100644
--- a/tests/test-throttle.c
+++ b/tests/test-throttle.c
@@ -14,6 +14,7 @@
#include <math.h>
#include "block/aio.h"
#include "qemu/throttle.h"
+#include "qemu/error-report.h"
static AioContext *ctx;
static LeakyBucket bkt;
@@ -492,10 +493,17 @@
int main(int argc, char **argv)
{
GSource *src;
+ Error *local_error = NULL;
init_clocks();
- ctx = aio_context_new();
+ ctx = aio_context_new(&local_error);
+ if (!ctx) {
+ error_report("Failed to create AIO Context: '%s'",
+ error_get_pretty(local_error));
+ error_free(local_error);
+ exit(1);
+ }
src = aio_get_g_source(ctx);
g_source_attach(src, NULL);
g_source_unref(src);
diff --git a/vl.c b/vl.c
index dc792fe..6d073c3 100644
--- a/vl.c
+++ b/vl.c
@@ -2968,6 +2968,7 @@
ram_addr_t maxram_size = default_ram_size;
uint64_t ram_slots = 0;
FILE *vmstate_dump_file = NULL;
+ Error *main_loop_err = NULL;
atexit(qemu_run_exit_notifiers);
error_set_progname(argv[0]);
@@ -3998,8 +3999,8 @@
os_daemonize();
- if (qemu_init_main_loop()) {
- fprintf(stderr, "qemu_init_main_loop failed\n");
+ if (qemu_init_main_loop(&main_loop_err)) {
+ error_report("%s", error_get_pretty(main_loop_err));
exit(1);
}
