ecbddbb106
When running virt-rescue the serial console hangs from time to time. Virt-rescue runs an ordinary Linux kernel "appliance", but there is only a single idle process running inside, so the qemu main loop is largely idle. With virt-rescue >= 1.37 you may be able to observe the hang by doing: $ virt-rescue -e ^] --scratch ><rescue> while true; do ls -l /usr/bin; done The hang in virt-rescue can be resolved by pressing a key on the serial console. Possibly with the same root cause, we also observed hangs during very early boot of regular Linux VMs with a serial console. Those hangs are extremely rare, but you may be able to observe them by running this command on baremetal for a sufficiently long time: $ while libguestfs-test-tool -t 60 >& /tmp/log ; do echo -n . ; done (Check in /tmp/log that the failure was caused by a hang during early boot, and not some other reason) During investigation of this bug, Paolo Bonzini wrote: > glib is expecting QEMU to use g_main_context_acquire around accesses to > GMainContext. However QEMU is not doing that, instead it is taking its > own mutex. So we should add g_main_context_acquire and > g_main_context_release in the two implementations of > os_host_main_loop_wait; these should undo the effect of Frediano's > glib patch. This patch exactly implements Paolo's suggestion in that paragraph. This fixes the serial console hang in my testing, across 3 different physical machines (AMD, Intel Core i7 and Intel Xeon), over many hours of automated testing. I wasn't able to reproduce the early boot hangs (but as noted above, these are extremely rare in any case). Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1435432 Reported-by: Richard W.M. Jones <rjones@redhat.com> Tested-by: Richard W.M. Jones <rjones@redhat.com> Signed-off-by: Richard W.M. Jones <rjones@redhat.com> Message-Id: <20170331205133.23906-1-rjones@redhat.com> [Paolo: this is actually a glib bug: recent glib versions are also expecting g_main_context_acquire around g_poll---but that is not documented and probably not even intended]. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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.. | ||
acl.c | ||
aio-posix.c | ||
aio-win32.c | ||
aiocb.c | ||
async.c | ||
base64.c | ||
bitmap.c | ||
bitops.c | ||
buffer.c | ||
bufferiszero.c | ||
compatfd.c | ||
coroutine-gthread.c | ||
coroutine-sigaltstack.c | ||
coroutine-ucontext.c | ||
coroutine-win32.c | ||
crc32c.c | ||
cutils.c | ||
envlist.c | ||
error.c | ||
event_notifier-posix.c | ||
event_notifier-win32.c | ||
fifo8.c | ||
getauxval.c | ||
hbitmap.c | ||
hexdump.c | ||
host-utils.c | ||
id.c | ||
iohandler.c | ||
iov.c | ||
keyval.c | ||
lockcnt.c | ||
log.c | ||
main-loop.c | ||
Makefile.objs | ||
memfd.c | ||
mmap-alloc.c | ||
module.c | ||
notify.c | ||
osdep.c | ||
oslib-posix.c | ||
oslib-win32.c | ||
path.c | ||
qdist.c | ||
qemu-config.c | ||
qemu-coroutine-io.c | ||
qemu-coroutine-lock.c | ||
qemu-coroutine-sleep.c | ||
qemu-coroutine.c | ||
qemu-error.c | ||
qemu-openpty.c | ||
qemu-option.c | ||
qemu-progress.c | ||
qemu-sockets.c | ||
qemu-thread-posix.c | ||
qemu-thread-win32.c | ||
qemu-timer-common.c | ||
qemu-timer.c | ||
qht.c | ||
range.c | ||
rcu.c | ||
readline.c | ||
systemd.c | ||
thread-pool.c | ||
throttle.c | ||
timed-average.c | ||
trace-events | ||
unicode.c | ||
uri.c | ||
uuid.c |