From 2f78e491d7b46542158ce0b8132ee4e05bc0ade4 Mon Sep 17 00:00:00 2001 From: Chrysostomos Nanakos Date: Thu, 18 Sep 2014 14:30:49 +0300 Subject: [PATCH] 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 Signed-off-by: Stefan Hajnoczi --- async.c | 16 +++++++++++----- include/block/aio.h | 2 +- include/qemu/main-loop.h | 2 +- iothread.c | 11 ++++++++++- main-loop.c | 9 +++++++-- qemu-img.c | 8 +++++++- qemu-io.c | 7 ++++++- qemu-nbd.c | 6 +++++- tests/test-aio.c | 10 +++++++++- tests/test-thread-pool.c | 10 +++++++++- tests/test-throttle.c | 10 +++++++++- vl.c | 5 +++-- 12 files changed, 78 insertions(+), 18 deletions(-) diff --git a/async.c b/async.c index a99e7f6..6e1b282 100644 --- a/async.c +++ b/async.c @@ -289,18 +289,24 @@ static void aio_rfifolock_cb(void *opaque) 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 @@ void aio_set_dispatching(AioContext *ctx, bool dispatching); * 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 @@ static void iothread_instance_finalize(Object *obj) { 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_instance_finalize(Object *obj) 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 @@ void qemu_notify_event(void) 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 @@ int qemu_init_main_loop(void) 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 @@ int main(int argc, char **argv) { 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 @@ int main(int argc, char **argv) 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 main(int argc, char **argv) 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 @@ int main(int argc, char **argv) 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 @@ int main(int argc, char **argv) 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 @@ static void test_source_timer_schedule(void) 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 @@ static void test_cancel_async(void) 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 #include "block/aio.h" #include "qemu/throttle.h" +#include "qemu/error-report.h" static AioContext *ctx; static LeakyBucket bkt; @@ -492,10 +493,17 @@ static void test_accounting(void) 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 @@ int main(int argc, char **argv, char **envp) 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 @@ int main(int argc, char **argv, char **envp) 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); } -- 2.7.4