Paolo Bonzini 158ef8cbb7 qemu-thread: fix qemu_event without futexes ...

This had a possible deadlock that was visible with rcutorture.

    qemu_event_set                    qemu_event_wait
    ----------------------------------------------------------------
                                      cmpxchg reads FREE, writes BUSY
                                      futex_wait: pthread_mutex_lock
                                      futex_wait: value == BUSY
    xchg reads BUSY, writes SET
    futex_wake: pthread_cond_broadcast
                                      futex_wait: pthread_cond_wait
                                      <deadlock>

The fix is simply to avoid condvar tricks and do the obvious locking
around pthread_cond_broadcast:

    qemu_event_set        qemu_event_wait
    ----------------------------------------------------------------
                                      cmpxchg reads FREE, writes BUSY
                                      futex_wait: pthread_mutex_lock
                                      futex_wait: value == BUSY
    xchg reads BUSY, writes SET
    futex_wake: pthread_mutex_lock
    (blocks)
                                      futex_wait: pthread_cond_wait
    (mutex unlocked)
    futex_wake: pthread_cond_broadcast
    futex_wake: pthread_mutex_unlock
                                      futex_wait: pthread_mutex_unlock

Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

2015-02-02 16:55:09 +01:00

..

acl.c

acl: fix memory leak

2014-11-17 11:48:56 +01:00

aes.c

util: Add InvMixColumns

2014-06-16 13:24:33 +02:00

bitmap.c

bitmap: use long as index

2014-01-13 14:04:53 +01:00

bitops.c

…

compatfd.c

Add a 'name' parameter to qemu_thread_create

2014-03-09 21:09:38 +02:00

crc32c.c

…

cutils.c

cutils: tighten qemu_parse_fd()

2014-05-08 14:19:58 -04:00

envlist.c

…

error.c

error: error_is_set() is finally unused; remove

2014-05-21 11:57:58 +02:00

event_notifier-posix.c

…

event_notifier-win32.c

…

fifo8.c

savevm: Remove all the unneeded version_minimum_id_old (arm)

2014-05-13 16:09:35 +01:00

getauxval.c

util: Move general qemu_getauxval to util/getauxval.c

2014-09-09 13:13:05 +02:00

hbitmap.c

util: Use g_new() & friends where that makes obvious sense

2014-12-10 11:34:15 +03:00

hexdump.c

…

host-utils.c

util: Don't link host-utils.o if it's empty

2014-09-09 13:13:05 +02:00

id.c

util: Emancipate id_wellformed() from QemuOpts

2014-10-03 10:30:33 +01:00

iov.c

util: Use g_new() & friends where that makes obvious sense

2014-12-10 11:34:15 +03:00

Makefile.objs

util: Emancipate id_wellformed() from QemuOpts

2014-10-03 10:30:33 +01:00

module.c

module: Don't complain when a module is absent

2014-07-18 14:57:35 +02:00

notify.c

…

osdep.c

do not call g_thread_init() for glib >= 2.31

2014-05-07 21:00:43 +04:00

oslib-posix.c

memory: expose alignment used for allocating RAM as MemoryRegion API

2014-11-23 12:11:30 +02:00

oslib-win32.c

memory: expose alignment used for allocating RAM as MemoryRegion API

2014-11-23 12:11:30 +02:00

path.c

util/path: Use the GLib memory allocation routines

2014-08-24 13:16:32 +04:00

qemu-config.c

qapi: output def_value_str when query command line options

2014-06-16 17:23:20 +08:00

qemu-error.c

qemu-error: Add error_vreport()

2014-10-09 15:36:15 +02:00

qemu-openpty.c

util/qemu-openpty: fix build with musl libc by include termios.h as fallback

2014-06-11 00:25:06 +01:00

qemu-option.c

block: Don't add trailing space in "Formating..." message

2014-12-12 16:52:33 +00:00

qemu-progress.c

qemu-progress: Fix progress printing on SIGUSR1

2014-01-24 14:33:00 +01:00

qemu-sockets.c

qemu-sockets: Add error to non-blocking connect handler

2014-10-09 15:36:15 +02:00

qemu-thread-posix.c

qemu-thread: fix qemu_event without futexes

2015-02-02 16:55:09 +01:00

qemu-thread-win32.c

qemu-thread: add per-thread atexit functions

2015-01-13 13:43:29 +00:00

qemu-timer-common.c

…

readline.c

readline: Clear screen on form feed.

2014-06-11 10:10:29 -04:00

rfifolock.c

rfifolock: add recursive FIFO lock

2014-03-13 14:42:21 +01:00

throttle.c

throttle: add throttle_detach/attach_aio_context()

2014-06-04 09:56:12 +02:00

unicode.c

…

uri.c

util: Fuse g_malloc(); memset() into g_new0()

2014-12-10 11:33:38 +03:00