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Kevin Wolf e424aff5f3 mirror: Fix coroutine reentrance
This fixes a regression introduced by commit dcfb3beb ("mirror: Do zero
write on target if sectors not allocated"), which was reported to cause
aborts with the message "Co-routine re-entered recursively".

The cause for this bug is the following code in mirror_iteration_done():

    if (s->common.busy) {
        qemu_coroutine_enter(s->common.co, NULL);
    }

This has always been ugly because - unlike most places that reenter - it
doesn't have a specific yield that it pairs with, but is more
uncontrolled.  What we really mean here is "reenter the coroutine if
it's in one of the four explicit yields in mirror.c".

This used to be equivalent with s->common.busy because neither
mirror_run() nor mirror_iteration() call any function that could yield.
However since commit dcfb3beb this doesn't hold true any more:
bdrv_get_block_status_above() can yield.

So what happens is that bdrv_get_block_status_above() wants to take a
lock that is already held, so it adds itself to the queue of waiting
coroutines and yields. Instead of being woken up by the unlock function,
however, it gets woken up by mirror_iteration_done(), which is obviously
wrong.

In most cases the code actually happens to cope fairly well with such
cases, but in this specific case, the unlock must already have scheduled
the coroutine for wakeup when mirror_iteration_done() reentered it. And
then the coroutine happened to process the scheduled restarts and tried
to reenter itself recursively.

This patch fixes the problem by pairing the reenter in
mirror_iteration_done() with specific yields instead of abusing
s->common.busy.

Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Message-id: 1439455310-11263-1-git-send-email-kwolf@redhat.com
Signed-off-by: Jeff Cody <jcody@redhat.com>
2015-08-14 09:51:31 -04:00
audio ossaudio: fix memory leak 2015-07-08 13:11:01 +02:00
backends hostmem: Fix qemu_opt_get_bool() crash in host_memory_backend_init() 2015-07-22 15:09:25 -03:00
block mirror: Fix coroutine reentrance 2015-08-14 09:51:31 -04:00
bsd-user bsd-user: Fix operand to cpu_x86_exec 2015-07-30 12:38:49 +01:00
crypto crypto: fix built-in AES decrypt function 2015-07-27 12:22:01 +02:00
default-configs smbios: move smbios code into a common folder 2015-08-13 14:08:30 +03:00
disas disas/arm-a64: Add missing compiler attribute GCC_FMT_ATTR 2015-07-21 11:18:45 +01:00
docs AioContext: optimize clearing the EventNotifier 2015-07-22 12:41:40 +01:00
dtc@65cc4d2748 dtc: Update dtc / libfdt submodule to version 1.4.0 2015-06-03 23:56:49 +02:00
fpu target-s390x: define default NaN values 2015-06-05 01:37:58 +02:00
fsdev virtfs-proxy-helper: fail gracefully if socket path is too long 2015-06-16 20:32:29 +05:30
gdb-xml gdb-xml: Include XML for s390 vector registers 2015-05-27 17:52:03 +02:00
hw MIPS patches 2015-08-13 2015-08-13 17:47:44 +01:00
include virtio,pc,acpi fixes, cleanups 2015-08-13 15:07:34 +01:00
libcacard libcacard: pkgconfig: tidy dependent libs 2015-06-23 19:57:28 +03:00
libdecnumber remove libdecnumber/dpd/decimal128Local.h 2015-06-23 19:57:27 +03:00
linux-headers linux-headers: Update to 4.2-rc1 2015-07-06 17:59:01 +02:00
linux-user linux-user: Fix MIPS N64 trap and break instruction bug 2015-07-15 14:07:25 +01:00
migration migration: Fix global state with Xen. 2015-08-03 16:13:23 +00:00
net net: Flush queued packets when guest resumes 2015-07-20 18:11:24 +01:00
pc-bios pseries: Update SLOF firmware image to qemu-slof-20150429 2015-07-07 17:44:49 +02:00
pixman@87eea99e44 pixman: update internal copy to pixman-0.32.6 2014-09-15 08:14:19 +02:00
po po: fix conflict with %.mo rule in rules.mak 2014-09-26 13:35:08 +02:00
qapi migration: create migration event 2015-07-07 14:54:55 +02:00
qga qga: fixed versions for guest bus types in qapi-schema 2015-07-21 14:36:06 -05:00
qobject Include qapi/qmp/qerror.h exactly where needed 2015-06-22 18:20:41 +02:00
qom cpu: Convert cpu_index into a bitmap 2015-07-09 15:20:40 +02:00
roms pseries: Update SLOF firmware image to qemu-slof-20150429 2015-07-07 17:44:49 +02:00
scripts virtio-input: move sys/ioctl.h include 2015-07-16 17:34:41 +02:00
slirp qerror: Move #include out of qerror.h 2015-06-22 18:20:40 +02:00
stubs main-loop: introduce qemu_mutex_iothread_locked 2015-07-01 15:45:50 +02:00
target-alpha cpu-exec: Purge all uses of ENV_GET_CPU() 2015-07-09 15:20:40 +02:00
target-arm target-arm: Add AArch32 banked register access to secure physical timer 2015-08-13 11:26:22 +01:00
target-cris disas: cris: QOMify target specific disas setup 2015-07-09 15:20:41 +02:00
target-i386 target-i386: Remove x86_cpu_compat_set_features() 2015-08-13 14:08:25 +03:00
target-lm32 cpu-exec: Purge all uses of ENV_GET_CPU() 2015-07-09 15:20:40 +02:00
target-m68k cpu-exec: Purge all uses of ENV_GET_CPU() 2015-07-09 15:20:40 +02:00
target-microblaze disas: microblaze: QOMify target specific disas setup 2015-07-09 15:20:41 +02:00
target-mips target-mips: Use CPU_LOG_INT for logging related to interrupts 2015-08-13 16:22:53 +01:00
target-moxie cpu-exec: Purge all uses of ENV_GET_CPU() 2015-07-09 15:20:40 +02:00
target-openrisc cpu-exec: Purge all uses of ENV_GET_CPU() 2015-07-09 15:20:40 +02:00
target-ppc cpu-exec: Purge all uses of ENV_GET_CPU() 2015-07-09 15:20:40 +02:00
target-s390x cpu-exec: Purge all uses of ENV_GET_CPU() 2015-07-09 15:20:40 +02:00
target-sh4 cpu-exec: Purge all uses of ENV_GET_CPU() 2015-07-09 15:20:40 +02:00
target-sparc cpu-exec: Purge all uses of ENV_GET_CPU() 2015-07-09 15:20:40 +02:00
target-tricore cpu-exec: Purge all uses of ENV_GET_CPU() 2015-07-09 15:20:40 +02:00
target-unicore32 cpu-exec: Purge all uses of ENV_GET_CPU() 2015-07-09 15:20:40 +02:00
target-xtensa cpu-exec: Purge all uses of ENV_GET_CPU() 2015-07-09 15:20:40 +02:00
tcg tcg/mips: fix add2 2015-08-01 09:39:50 +02:00
tests smbios: move smbios code into a common folder 2015-08-13 14:08:30 +03:00
trace Remove superfluous '\n' around error_report() 2015-03-10 08:15:33 +03:00
ui vnc: fix memory leak 2015-07-24 13:57:44 +02:00
util rcu: actually register threads that have RCU read-side critical sections 2015-07-24 13:57:45 +02:00
.exrc qemu: add .exrc 2012-09-07 09:02:44 +03:00
.gitignore gitignore: Ignore shader generated files 2015-07-27 22:44:47 +03:00
.gitmodules PPC: Add u-boot firmware for e500 2014-06-16 13:24:35 +02:00
.mailmap Update mailmap 2013-09-05 09:40:31 -05:00
.travis.yml .travis.yml: Add "--enable-modules" 2015-01-26 12:27:05 +01:00
accel.c accel: Create accel object when initializing machine 2014-10-09 15:36:14 +02:00
aio-posix.c AioContext: optimize clearing the EventNotifier 2015-07-22 12:41:40 +01:00
aio-win32.c AioContext: optimize clearing the EventNotifier 2015-07-22 12:41:40 +01:00
arch_init.c smbios: move smbios code into a common folder 2015-08-13 14:08:30 +03:00
async.c AioContext: force event loop iteration using BH 2015-07-29 10:02:06 +01:00
balloon.c Include monitor/monitor.h exactly where needed 2015-06-22 18:20:41 +02:00
block.c block: Fix backing file child when modifying graph 2015-07-14 17:15:23 +02:00
blockdev-nbd.c Include monitor/monitor.h exactly where needed 2015-06-22 18:20:41 +02:00
blockdev.c mirror: correct buf_size 2015-07-14 21:50:13 -04:00
blockjob.c blockjob: add block_job_release function 2015-07-07 14:27:14 +01:00
bootdevice.c misc: fix typos in copyright declaration 2015-03-26 14:21:43 +01:00
bt-host.c sysemu: avoid proliferation of include/ subdirectories 2013-04-15 18:19:25 +02:00
bt-vhci.c sysemu: avoid proliferation of include/ subdirectories 2013-04-15 18:19:25 +02:00
Changelog Use qemu-project.org domain name 2013-10-11 09:34:56 -07:00
CODING_STYLE CODING_STYLE: Section about conditional statement 2014-08-15 18:54:06 +04:00
configure configure: Drop vnc-ws feature from help text 2015-08-03 15:32:17 +01:00
COPYING
COPYING.LIB
coroutine-gthread.c glib-compat.h: add new thread API emulation on top of pre-2.31 API 2014-06-10 07:44:01 +02:00
coroutine-sigaltstack.c coroutine-sigaltstack: Change jmp_buf to sigjmp_buf 2014-11-11 11:07:55 +03:00
coroutine-ucontext.c coroutine-ucontext: use __thread 2015-01-13 13:43:28 +00:00
coroutine-win32.c coroutine-win32.c: Add noinline attribute to work around gcc bug 2014-06-26 14:08:14 +01:00
cpu-exec.c cpu-exec: Purge all uses of ENV_GET_CPU() 2015-07-09 15:20:40 +02:00
cpus.c rcu: actually register threads that have RCU read-side critical sections 2015-07-24 13:57:45 +02:00
cputlb.c memory: replace cpu_physical_memory_reset_dirty() with test-and-clear 2015-06-05 17:10:00 +02:00
device_tree.c device_tree: Fix a typo 2015-07-27 22:44:47 +03:00
device-hotplug.c pci-hotplug-old: Has been dead for five major releases, bury 2015-03-01 12:37:54 +01:00
disas.c disas: cris: QOMify target specific disas setup 2015-07-09 15:20:41 +02:00
dma-helpers.c range: remove useless inclusions 2015-04-30 16:05:48 +03:00
dump.c Include qapi/qmp/qerror.h exactly where needed 2015-06-22 18:20:41 +02:00
exec.c exec.c: Use atomic_rcu_read() to access dispatch in memory_region_section_get_iotlb() 2015-07-23 07:37:38 +02:00
gdbstub.c gdbstub: Set current CPU on interruptions 2015-07-27 22:46:16 +03:00
HACKING HACKING: Document vaddr type usage 2013-07-23 02:41:31 +02:00
hmp-commands.hx qmp/hmp: add rocker device support 2015-06-12 13:42:17 +01:00
hmp.c qmp: Add optional bool "unmap" to drive-mirror 2015-07-02 10:06:23 +01:00
hmp.h qmp/hmp: add rocker device support 2015-06-12 13:42:17 +01:00
iohandler.c iohandler: Change return type of qemu_set_fd_handler to "void" 2015-06-12 13:26:21 +01:00
ioport.c - miscellaneous cleanups for TCG (Emilio) and NBD (Bogdan) 2015-04-30 12:04:11 +01:00
iothread.c rcu: actually register threads that have RCU read-side critical sections 2015-07-24 13:57:45 +02:00
kvm-all.c VFIO updates for 2.4-rc0 2015-07-07 09:22:40 +01:00
kvm-stub.c kvm: some fixes to kvm_resamplefds_allowed 2015-07-06 12:15:14 -06:00
LICENSE vfio: move hw/misc/vfio.c to hw/vfio/pci.c Move vfio.h into include/hw/vfio 2014-12-19 15:24:06 -07:00
main-loop.c main-loop: fix qemu_notify_event for aio_notify optimization 2015-07-27 17:12:19 +01:00
MAINTAINERS MAINTAINERS: list smbios maintainers 2015-08-13 14:08:31 +03:00
Makefile make: Clean build messages 2015-07-27 22:44:47 +03:00
Makefile.objs crypto: introduce new module for computing hash digests 2015-07-07 12:04:07 +02:00
Makefile.target migration: move savevm.c inside migration/ 2015-06-12 06:42:30 +02:00
memory_mapping.c memory_mapping: Rework cpu related includes 2015-06-26 16:00:50 +02:00
memory.c Merge memory_region_init_reservation() into memory_region_init_io() 2015-08-13 11:26:21 +01:00
module-common.c module: implement module loading 2014-02-20 13:14:18 +01:00
monitor.c Include qapi/qmp/qerror.h exactly where needed 2015-06-22 18:20:41 +02:00
nbd.c qemu-nbd: only send a limited number of errno codes on the wire 2015-05-08 14:45:11 +02:00
numa.c numa: Fix memory leak in numa_set_mem_node_id() 2015-07-15 16:57:50 -03:00
os-posix.c rcu: do not create thread in pthread_atfork callback 2015-04-01 10:06:38 +02:00
os-win32.c pidfile: stop making pidfile error a special case 2014-11-02 10:04:34 +03:00
page_cache.c xbzrle: rebuild the cache_is_cached function 2015-01-15 17:49:43 +05:30
qapi-schema.json qapi: add missing @ 2015-07-27 22:44:47 +03:00
qdev-monitor.c Include qapi/qmp/qerror.h exactly where needed 2015-06-22 18:20:41 +02:00
qdict-test-data.txt
qemu-bridge-helper.c qemu-bridge-helper: Fix fd leak in main() 2014-06-27 10:39:10 +02:00
qemu-char.c qemu-char: Fix missed data on unix socket 2015-07-23 07:37:38 +02:00
qemu-coroutine-io.c coroutine-io: Return -errno in case of error 2015-03-18 12:07:21 +01:00
qemu-coroutine-lock.c coroutine: remove unnecessary parentheses in qemu_co_queue_empty 2015-04-30 16:05:49 +03:00
qemu-coroutine-sleep.c coroutine: Drop co_sleep_ns 2014-08-29 10:46:58 +01:00
qemu-coroutine.c coroutine: Clean up qemu_coroutine_enter() 2015-03-09 11:11:59 +01:00
qemu-doc.texi qemu-doc: fix typos 2015-07-24 13:57:45 +02:00
qemu-img-cmds.hx qemu-img: Add progress output for amend 2014-11-03 11:41:48 +00:00
qemu-img.c Include qapi/qmp/qerror.h exactly where needed 2015-06-22 18:20:41 +02:00
qemu-img.texi qemu-img: Add progress output for amend 2014-11-03 11:41:48 +00:00
qemu-io-cmds.c qerror: Move #include out of qerror.h 2015-06-22 18:20:40 +02:00
qemu-io.c qerror: Move #include out of qerror.h 2015-06-22 18:20:40 +02:00
qemu-log.c qemu-log: Correct help text of 'log cpu_reset' 2015-02-10 09:27:20 +03:00
qemu-nbd.c qerror: Move #include out of qerror.h 2015-06-22 18:20:40 +02:00
qemu-nbd.texi nbd: Miscellaneous typo fixes. 2014-05-24 00:07:29 +04:00
qemu-options-wrapper.h vl.c: In qemu -h output, only print options for the arch we are running as 2011-12-19 10:27:33 -06:00
qemu-options.h
qemu-options.hx qemu-doc: fix typos 2015-07-24 13:57:45 +02:00
qemu-seccomp.c seccomp: add mlockall to whitelist 2015-01-23 14:07:08 +01:00
qemu-tech.texi qemu-doc: fix typos 2015-07-24 13:57:45 +02:00
qemu-timer.c qemu-timer: initialize "timers_done_ev" to set 2015-07-22 12:41:32 +01:00
qemu.nsi nsis: Improved support for parallel installation of 32 and 64 bit code 2013-11-07 07:02:44 +01:00
qemu.sasl sasl: Avoid 'Could not find keytab file' in syslog 2014-03-15 13:54:18 +04:00
qjson.c QJSON: Use OBJECT_CHECK 2015-05-11 08:59:07 -04:00
qmp-commands.hx migration: Write documetation for events capabilites 2015-07-15 09:07:54 +02:00
qmp.c Include monitor/monitor.h exactly where needed 2015-06-22 18:20:41 +02:00
qtest.c qtest: pre-buffer hex nibs 2015-05-22 15:58:22 -04:00
README Use qemu-project.org domain name 2013-10-11 09:34:56 -07:00
rules.mak make: load only required dependency files. 2015-08-13 14:08:25 +03:00
softmmu_template.h softmmu: Add probe_write() 2015-06-11 10:13:28 +01:00
spice-qemu-char.c spice: fix spice_chr_add_watch() pre-condition 2015-05-29 09:56:01 +02:00
tcg-runtime.c tcg: Push tcg-runtime routines into exec/helper-* 2014-05-28 09:33:54 -07:00
tci.c tcg: Mask TCGMemOp appropriately for indexing 2015-06-09 06:35:29 -07:00
thread-pool.c thread-pool: clean up thread_pool_completion_bh() 2015-04-28 15:36:09 +02:00
thunk.c linux-user: Allocate thunk size dynamically 2015-06-15 11:36:58 +03:00
tpm.c Include monitor/monitor.h exactly where needed 2015-06-22 18:20:41 +02:00
trace-events block/mirror: limit qiov to IOV_MAX elements 2015-08-06 04:41:09 -04:00
translate-all.c translate-all: Change tb_flush() env argument to cpu 2015-07-09 15:20:40 +02:00
translate-all.h translate-all: remove unnecessary argument to tb_invalidate_phys_range 2015-06-05 17:09:59 +02:00
user-exec.c exec: move functions to translate-all.h 2015-06-05 17:09:59 +02:00
VERSION Open 2.5 development tree 2015-08-11 23:15:55 +01:00
version.rc Use qemu-project.org domain name 2013-10-11 09:34:56 -07:00
vl.c smbios: move smbios code into a common folder 2015-08-13 14:08:30 +03:00
xen-common-stub.c accel: Move Xen registration code to xen-common.c 2014-10-04 08:59:15 +02:00
xen-common.c migration: Fix regression for xenfv and pc,accel=xen machine. 2015-08-03 16:13:40 +00:00
xen-hvm-stub.c xen: Remove xen_cmos_set_s3_resume() 2015-03-10 08:15:33 +03:00
xen-hvm.c xen-220615, more SOB lines 2015-06-23 17:46:20 +01:00
xen-mapcache.c xen: add a lock for the mapcache 2015-01-20 14:24:17 +00:00

Read the documentation in qemu-doc.html or on http://wiki.qemu-project.org

- QEMU team