diff options
Diffstat (limited to 'results/scraper/launchpad-without-comments/1399943')
| -rw-r--r-- | results/scraper/launchpad-without-comments/1399943 | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/results/scraper/launchpad-without-comments/1399943 b/results/scraper/launchpad-without-comments/1399943 new file mode 100644 index 000000000..689890de0 --- /dev/null +++ b/results/scraper/launchpad-without-comments/1399943 @@ -0,0 +1,28 @@ +qemu-system-sparc loses serial console data on EAGAIN + +When running a guest OS with a serial console under +"qemu-system-sparc -nographic", parts of the serial console output +are sometimes lost. + +This happens when a write() to standard output by qemu returns EAGAIN, +as may be the case when the guest is generating console output faster +than the tty (or pty/pipe/socket, etc.) connected to qemu's standard +output accepts it. The bug affects all releases of qemu since 1.5, +which was the first version to set stdout to O_NONBLOCK mode. Version +1.4.2 and earlier work correctly. + +To reproduce the bug, you will need a guest OS configured with a +serial console, and a host with a slow tty. The attached shell script +"sparc-test.sh" does this by using Aboriginal Linux as the serial +console guest, and a pty controlled by a Python script and the +"pexpect" Python module as the slow tty. A "seq" command is sent +to the guest to generate 100,000 lines of output containing sequential +integers, and the output is checked for gaps. The script limits the +tty output rate by occasionally sleeping for 1/10 of a second. + +This bug was originally reported against qemu-system-i386 as +bug #1335444, and has since been fixed in qemu-system-i386, +but remains in qemu-system-sparc as of today's git sources +(d00e6cddc220de993573dfb5fd160ac72ccd49ab). I am opening +this separate bug for the sparc case because I was asked +to do so by Paolo Bonzini in #1335444. \ No newline at end of file |