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 a99e7f639..6e1b282aa 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 67a75ddd5..156272177 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 6f0200a7a..62c68c0f3 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 d9403cf69..342a23fcb 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 3cc79f82f..53393a4b1 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 91d1ac3d7..dbf0904dc 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 d2ab6946e..66cf3ef4b 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 9bc152e6c..de9963f8f 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 c6a8713e8..a7cb5c991 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 ed2b25b8e..8c4d68b34 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 000ae31af..d8ba415e4 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 dc792fe08..6d073c357 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); } -- 2.39.5