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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 | ||