On Fri, Jul 06, 2012 at 08:45:44PM +0300, Jukka Ollila wrote: > Hello, > > A few days ago I filed a kernel regression report concerning a change > in /proc/kmsg behaviour with short reads: > > https://bugzilla.kernel.org/show_bug.cgi?id=44211 > > The comments suggest that this is probably intentional, but that it > would be best make sure that the current semantics wrt short reads are > as intended. > > The problem appears on a Debian (unstable) system that drains > /proc/kmsg into a separate fifo read by klogd(8): > > /bin/dd bs=1 if=/proc/kmsg of=/var/run/klogd/kmsg > > With the recent kernel logging changes this /bin/dd exits immediately, > as 1-byte reads are shorter than any log message could possibly be and > read() returns 0. No dd feeding the fifo results in no logging and a > rather unhappy klogd on the reading end of /var/run/klogd/kmsg. > > I suppose a safe solution is to only do reads that are big enough for > any single kernel message, but this is still a change that affects > user space being shipped, so some might find it surprising. > > I don't know what other distros do. Is it just Debian being the odd one out?
I think we just fixed this, what kernel version are you seeing this problem on? Kay did your other patches that I just accepted resolve this? thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
