xemu/util
Stefan Hajnoczi e62da98527 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>
2023-03-27 15:12:17 +02:00
..
aio-posix.c aio: make aio_set_fd_poll() static to aio-posix.c 2023-03-13 15:23:37 +04:00
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 win32: avoid mixing SOCKET and file descriptor space 2023-03-13 15:39:31 +04:00
aiocb.c block: move AioContext, QEMUTimer, main-loop to libqemuutil 2017-02-21 11:14:07 +00:00
async-teardown.c Fix non-first inclusions of qemu/osdep.h 2023-02-08 07:28:05 +01:00
async.c async: clarify usage of barriers in the polling case 2023-03-07 12:39:53 +01:00
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 replace TABs with spaces 2023-03-20 12:43:50 +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 include/qemu/cpuid: Introduce xgetbv_low 2023-03-05 13:44:07 -08:00
cacheflush.c util/cacheflush: fix cache on windows-arm64 2023-02-21 08:53:03 -10:00
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
crc-ccitt.c util: Add CRC16 (CCITT) calculation routines 2021-01-24 20:10:54 +01:00
crc32c.c Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
cutils.c util: remove support for hex numbers with a scaling suffix 2023-01-06 00:51:02 +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 replace TABs with spaces 2023-03-20 12:43:50 +01:00
error-report.c util/error: add G_GNUC_PRINTF for various functions 2023-01-11 10:44:34 +01:00
error.c error: add global &error_warn destination 2023-03-13 15:23:37 +04:00
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() 2023-03-27 15:12:17 +02:00
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 replay: Extract core API to 'exec/replay-core.h' 2023-02-27 22:29:01 +01:00
hbitmap.c hbitmap: fix hbitmap_status() return value for first dirty bit case 2023-02-17 14:34:24 +01:00
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 include/qemu/int128: Use Int128 structure for TCI 2023-02-04 06:19:42 -10:00
interval-tree.c util: Add interval-tree.c 2022-12-20 17:09:41 -08:00
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 log: Remove unneeded new line 2023-03-08 00:37:48 +01:00
main-loop.c main-loop: remove qemu_fd_register(), win32/slirp/socket specific 2023-03-13 15:39:31 +04:00
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 accel: introduce accelerator blocker API 2023-01-11 09:59:39 +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 error handling: Use RETRY_ON_EINTR() macro where applicable 2023-01-09 13:50:47 +01:00
oslib-posix.c util: drop qemu_fork() 2023-03-13 15:23:37 +04:00
oslib-win32.c win32: add qemu_close_socket_osfhandle() 2023-03-21 11:16:03 +04:00
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 error: Drop superfluous #include "qapi/qmp/qerror.h" 2023-02-23 13:56:14 +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 qemu-coroutine-lock: add smp_mb__after_rmw() 2023-03-07 12:39:53 +01:00
qemu-coroutine-sleep.c coroutine: Clean up superfluous inclusion of qemu/coroutine.h 2023-01-19 10:18:28 +01:00
qemu-coroutine.c coroutine: Clean up superfluous inclusion of qemu/coroutine.h 2023-01-19 10:18:28 +01:00
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 win32: replace closesocket() with close() wrapper 2023-03-13 15:39:31 +04:00
qemu-thread-common.h Clean up includes 2018-12-20 10:29:08 +01:00
qemu-thread-posix.c qemu-thread-posix: cleanup, fix, document QemuEvent 2023-03-07 12:38:40 +01:00
qemu-thread-win32.c qemu-thread-win32: cleanup, fix, document QemuEvent 2023-03-07 12:38:40 +01:00
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 util/qht: use striped locks under TSAN 2023-02-02 11:48:20 +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: Extract readline_add_completion_of() from monitor 2023-02-04 07:56:54 +01:00
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 qapi: Use returned bool to check for failure (again) 2022-12-14 16:19:35 +01:00
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 util/userfaultfd: Support /dev/userfaultfd 2023-02-11 16:51:09 +01:00
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 Updated the FSF address to <https://www.gnu.org/licenses/> 2023-02-27 09:15:39 +01:00
userfaultfd.c util/userfaultfd: Support /dev/userfaultfd 2023-02-11 16:51:09 +01:00
uuid.c Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
vfio-helpers.c error handling: Use RETRY_ON_EINTR() macro where applicable 2023-01-09 13:50:47 +01:00
vhost-user-server.c block/export: only acquire AioContext once for vhost_user_server_stop() 2023-03-27 13:46:30 +02:00
yank.c yank: Remove dependency on qiochannel 2021-04-01 15:27:44 +04:00