On 09/27/2011 08:33 PM, Paul Eggert wrote: > This happened with coreutils 8.13 on Fedora 14 x86-64 > (coreutils compiled with GCC 4.6.1). I interrupted > 'dd' with control-C, but it didn't respond right away; > instead, it churned away and created the entire output file, > issuing a bogus diagnostic about the input file. Here's > the transcript: > > $ dd if=/dev/zero of=$HOME/junk/zero bs=1024 count=1000000 > ^C1000000+0 records in > 1000000+0 records out > 1024000000 bytes (1.0 GB) copied, 20.1583 s, 50.8 MB/s > dd: closing input file `/dev/zero': Bad file descriptor > $ ls -l zero > -rw-r--r-- 1 eggert eggert 1024000000 Sep 27 12:18 zero > > The problem with the diagnostic is intermittent. It usually > does not happen. Usually, there's simply an unconscionably long > wait between the time I type ^C and the time that dd exits, e.g.: > > $ dd if=/dev/zero of=zero bs=1024 count=1000000 > ^C487034+0 records in > 487034+0 records out > 498722816 bytes (499 MB) copied, 11.6897 s, 42.7 MB/s > > (here I waited about 10 seconds between the time I typed > ^C and the time that dd exited). > > The filesystem is ext4 atop md (RAID-1). > > The same problem occurs with /bin/dd (coreutils 8.5) so > if it is a coreutils bug it's not a new one. > > Don't have time to debug this right now but thought I'd > get a bug report into the system. Quite possibly it is not > a coreutils bug at all, but a kernel bug, but in that case > where do I report it? to a Fedora mailing list?
I think this is a kernel signal propagation bug that I noticed on Fedora 14 too and I think Linda Walsh reported the same thing on the kernel list. I didn't notice it on later kernels so I didn't pursue it. Note I didn't notice errors, just delays. BTW that ^C being displayed (started around Fedora 11 time (2.6.30)) is very annoying, especially when inserted in the middle of an ANSI code. I mentioned that previously here: http://mail.linux.ie/pipermail/ilug/2011-February/106723.html cheers, Pádraig.
