xemu/util
Stefan Hajnoczi 248aa3deb6 aio-posix: fix race between epoll upgrade and aio_set_fd_handler()
If another thread calls aio_set_fd_handler() while the IOThread event
loop is upgrading from ppoll(2) to epoll(7) then we might miss new
AioHandlers. The epollfd will not monitor the new AioHandler's fd,
resulting in hangs.

Take the AioHandler list lock while upgrading to epoll. This prevents
AioHandlers from changing while epoll is being set up. If we cannot lock
because we're in a nested event loop, then don't upgrade to epoll (it
will happen next time we're not in a nested call).

The downside to taking the lock is that the aio_set_fd_handler() thread
has to wait until the epoll upgrade is finished, which involves many
epoll_ctl(2) system calls. However, this scenario is rare and I couldn't
think of another solution that is still simple.

Reported-by: Qing Wang <qinwang@redhat.com>
Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2090998
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Fam Zheng <fam@euphon.net>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230323144859.1338495-1-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit e62da98527fa35fe5f532cded01a33edf9fbe7b2)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2023-04-10 11:16:14 +03:00
..
aio-posix.c util/event-loop-base: Introduce options to set the thread pool size 2022-05-09 10:43:23 +01:00
aio-posix.h aio-posix: fix spurious ->poll_ready() callbacks in main loop 2022-03-17 11:23:18 +00:00
aio-wait.c aio_wait_kick: add missing memory barrier 2022-06-24 17:07:06 +02:00
aio-win32.c util/aio-win32: Correct the event array size in aio_poll() 2022-11-06 09:48:26 +01:00
aiocb.c block: move AioContext, QEMUTimer, main-loop to libqemuutil 2017-02-21 11:14:07 +00:00
async-teardown.c os-posix: asynchronous teardown for shutdown on Linux 2022-10-31 09:46:34 +01:00
async.c replay: notify vCPU when BH is scheduled 2022-06-06 09:26:53 +02:00
atomic64.c osdep: Move memalign-related functions to their own header 2022-03-07 13:16:49 +00:00
base64.c nomaintainer: Fix Lesser GPL version number 2020-11-15 17:04:40 +01:00
bitmap.c migration: Use non-atomic ops for clear log bitmap 2022-11-21 11:58:10 +01:00
bitops.c avoid TABs in files that only contain a few 2019-01-11 15:46:56 +01:00
block-helpers.c block: move logical block size check function to a common utility function 2020-10-23 13:42:16 +01:00
block-helpers.h block: move logical block size check function to a common utility function 2020-10-23 13:42:16 +01:00
buffer.c nomaintainer: Fix Lesser GPL version number 2020-11-15 17:04:40 +01:00
bufferiszero.c cpuid: use unsigned for max cpuid 2022-02-04 09:07:43 -05:00
cacheflush.c util/cacheflush: Optimize flushing when ppc host has coherent icache 2022-06-21 09:28:41 -07:00
compatfd.c util: replace pipe()+cloexec with g_unix_open_pipe() 2022-05-03 15:18:14 +04:00
coroutine-sigaltstack.c Remove qemu-common.h include from most units 2022-04-06 14:31:55 +02:00
coroutine-ucontext.c coroutine-ucontext: use QEMU_DEFINE_STATIC_CO_TLS() 2022-05-04 15:55:23 +02:00
coroutine-win32.c coroutine-win32: use QEMU_DEFINE_STATIC_CO_TLS() 2022-05-04 15:55:23 +02:00
crc32c.c Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
crc-ccitt.c util: Add CRC16 (CCITT) calculation routines 2021-01-24 20:10:54 +01:00
cutils.c cutils: Add missing dyld(3) include on macOS 2022-08-12 11:33:52 +01:00
dbus.c util: add dbus helper unit 2020-01-06 18:41:32 +04:00
drm.c util/drm: make portable by avoiding struct dirent d_type 2020-07-13 14:36:10 +01:00
envlist.c Use g_new() & friends where that makes obvious sense 2022-03-21 15:44:44 +01:00
error-report.c error-report: fix g_date_time_format assertion 2022-04-28 08:51:56 +02:00
error.c error: make Error **errp const where it is appropriate 2019-12-18 08:36:16 +01:00
event_notifier-posix.c Replace qemu_pipe() with g_unix_open_pipe() 2022-05-03 15:17:56 +04:00
event_notifier-win32.c Remove qemu-common.h include from most units 2022-04-06 14:31:55 +02:00
fdmon-epoll.c aio-posix: fix race between epoll upgrade and aio_set_fd_handler() 2023-04-10 11:16:14 +03:00
fdmon-io_uring.c aio-posix: fix build failure io_uring 2.2 2022-03-17 11:23:18 +00:00
fdmon-poll.c fdmon-poll: reset npfd when upgrading to fdmon-epoll 2020-09-23 13:45:52 +01:00
fifo8.c utils/fifo8: change fatal errors from abort() to assert() 2021-02-07 20:38:20 +00:00
filemonitor-inotify.c nomaintainer: Fix Lesser GPL version number 2020-11-15 17:04:40 +01:00
filemonitor-stub.c nomaintainer: Fix Lesser GPL version number 2020-11-15 17:04:40 +01:00
getauxval.c util/getauxval: Porting to FreeBSD getauxval feature 2020-06-26 06:45:29 -04:00
guest-random.c util/guest-random: Fix size arg to tail memcpy 2021-07-09 18:42:46 +02:00
hbitmap.c block: simplify handling of try to merge different sized bitmaps 2022-06-24 17:07:06 +02:00
hexdump.c include: move C/util-related declarations to cutils.h 2022-04-06 14:31:43 +02:00
host-utils.c host-utils: Implemented signed 256-by-128 division 2022-06-20 08:38:58 -03:00
id.c net: Use id_generate() in the network subsystem, too 2021-03-09 21:47:45 +01:00
int128.c qemu/int128: addition of div/rem 128-bit operations 2022-01-08 15:46:10 +10:00
iov.c util: make do_send_recv work with partial send/recv 2022-10-12 19:22:01 +04:00
iova-tree.c util: accept iova_tree_remove_parameter by value 2022-09-02 10:22:39 +08:00
keyval.c include: add qemu/keyval.h 2022-04-21 17:03:51 +04:00
lockcnt.c qemu/atomic.h: rename atomic_ to qatomic_ 2020-09-23 16:07:44 +01:00
log.c util/log: Ignore per-thread flag if global file already there 2022-11-07 16:00:02 -05:00
main-loop.c util/main-loop: Avoid adding the same HANDLE twice 2022-11-06 09:48:26 +01:00
memalign.c osdep: Move memalign-related functions to their own header 2022-03-07 13:16:49 +00:00
memfd.c linux-user: add memfd_create 2019-09-11 08:46:17 +02:00
meson.build qga: Allow building of the guest agent without system emulators or tools 2022-11-11 09:17:45 +01:00
mmap-alloc.c util/mmap-alloc: Remove qemu_mempath_getpagesize() 2022-08-26 13:34:21 +02:00
module.c module: add Error arguments to module_load and module_load_qom 2022-11-06 09:48:50 +01:00
notify.c xen / notify: introduce a new XenWatchList abstraction 2019-09-24 12:18:47 +01:00
nvdimm-utils.c Clean up includes 2020-12-10 17:16:44 +01:00
osdep.c tests/qtest: Use send/recv for socket communication 2022-10-28 11:17:12 +02:00
oslib-posix.c util: Make qemu_prealloc_mem() optionally consume a ThreadContext 2022-10-27 11:00:56 +02:00
oslib-win32.c util: Make qemu_prealloc_mem() optionally consume a ThreadContext 2022-10-27 11:00:56 +02:00
path.c util/path: Do not cache all filenames at startup 2019-06-24 22:19:30 +02:00
qdist.c qdist: return "(empty)" instead of NULL when printing an empty dist 2016-08-03 18:44:56 +02:00
qemu-co-shared-resource.c co-shared-resource: protect with a mutex 2021-06-25 14:24:24 +03:00
qemu-co-timeout.c util: add qemu-co-timeout 2022-06-29 10:56:12 +03:00
qemu-config.c Revert "s390x/s390-virtio-ccw: add zpcii-disable machine property" 2022-11-08 10:10:57 +01:00
qemu-coroutine-io.c Remove qemu-common.h include from most units 2022-04-06 14:31:55 +02:00
qemu-coroutine-lock.c coroutine: add flag to re-queue at front of CoQueue 2022-10-26 14:56:42 -04:00
qemu-coroutine-sleep.c coroutine-sleep: introduce qemu_co_sleep 2021-05-21 18:22:33 +01:00
qemu-coroutine.c coroutine: remove incorrect coroutine_fn annotations 2022-10-07 12:11:40 +02:00
qemu-option.c qemu-option: Allow deleting opts during qemu_opts_foreach() 2021-10-15 16:11:22 +02:00
qemu-print.c monitor: Use getter/setter functions for cur_mon 2020-10-09 07:08:19 +02:00
qemu-progress.c include: move progress API to qemu-progress.h 2022-04-06 14:31:43 +02:00
qemu-sockets.c -----BEGIN PGP SIGNATURE----- 2022-10-30 18:30:01 -04:00
qemu-thread-common.h Clean up includes 2018-12-20 10:29:08 +01:00
qemu-thread-posix.c util: Introduce qemu_thread_set_affinity() and qemu_thread_get_affinity() 2022-10-27 11:00:36 +02:00
qemu-thread-win32.c util: Introduce qemu_thread_set_affinity() and qemu_thread_get_affinity() 2022-10-27 11:00:36 +02:00
qemu-timer-common.c semihosting: Implement SYS_ELAPSED and SYS_TICKFREQ 2021-01-18 10:05:06 +00:00
qemu-timer.c qemu-timer: Skip empty timer lists before locking in qemu_clock_deadline_ns_all 2022-06-21 09:24:34 -07:00
qht.c osdep: Move memalign-related functions to their own header 2022-03-07 13:16:49 +00:00
qsp.c qemu/atomic: Add aligned_{int64,uint64}_t types 2021-07-21 07:45:38 -10:00
range.c Don't talk about the LGPL if the file is licensed under the GPL 2019-01-30 10:51:20 +01:00
rcu.c rcu: use coroutine TLS macros 2022-03-04 18:14:40 +01:00
readline.c readline: Fix possible array index out of bounds in readline_hist_add() 2021-01-04 11:13:39 +00:00
selfmap.c util/selfmap: Discard mapping on error 2021-07-26 07:06:49 -10:00
stats64.c qemu/atomic.h: rename atomic_ to qatomic_ 2020-09-23 16:07:44 +01:00
sys_membarrier.c sys_membarrier: fix up include directives 2018-04-05 14:37:38 +02:00
systemd.c tools: Fix use of fcntl(F_SETFD) during socket activation 2020-05-04 14:54:35 -05:00
thread-context.c util: Add write-only "node-affinity" property for ThreadContext 2022-10-27 11:00:50 +02:00
thread-pool.c thread-pool: remove stopping variable 2022-05-25 21:26:26 +02:00
throttle.c Remove superfluous timer_del() calls 2021-01-08 15:13:38 +00:00
timed-average.c Fix some typos found by codespell 2016-05-18 15:04:27 +03:00
trace-events modules: add tracepoints 2021-07-09 18:20:27 +02:00
trace.h trace: switch position of headers to what Meson requires 2020-08-21 06:18:24 -04:00
transactions.c transactions: Invoke clean() after everything else 2021-11-16 09:43:44 +01:00
unicode.c json: Reject invalid UTF-8 sequences 2018-08-24 20:26:37 +02:00
uri.c util/uri: do not check argument of uri_free() 2021-07-09 12:26:05 +02:00
userfaultfd.c migration: introduce UFFD-WP low-level interface helpers 2021-02-08 11:19:51 +00:00
uuid.c Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
vfio-helpers.c numa: call ->ram_block_removed() in ram_block_notifer_remove() 2022-10-26 14:56:42 -04:00
vhost-user-server.c util: rename qemu_*block() socket functions 2022-05-03 15:53:20 +04:00
yank.c yank: Remove dependency on qiochannel 2021-04-01 15:27:44 +04:00