So the story with this patch is that I was looking at the code for unrelated reasons and I was just dorking in my editor and decided to click send at the end. I often muck about and then just decide to move on without hitting send. It's not something I feel strongly about. On Fri, Dec 16, 2016 at 03:35:34PM -0500, Mike Marshall wrote: > 2) Some system administrators have admonished me because > of a place where I put annoying messages into the ring > buffer when a particular error occurs during op processing. > I liked seeing it during development, but on a busy production cluster > filled with people hitting CTRL-C and whatever else people whimsically > do, there were thousands of "No one's waiting for tag #such-and-such" > messages in dmesg and syslog. > > This particular message you mention, though, should almost never > come out, and never because of Joe Blow users, rather because > some awful thing happened when the sysadmin tried to load the > client-core (userspace connector). Wouldn't something important > have to be broken for that copy_from_user to fail? > > Anyhow, let me know if you think it might be OK to leave this one > in, else I'll take it out. If the user passes a bogus pointer to the ioctl, then copy_from_user() will fail and the program will segfault. It's simple enough to run valgrind or strace on the failing program and figure out why the program segfaulted surely? I don't know this code well enough, can regular users call the ORANGEFS_DEV_CLIENT_STRING? If so then they can trigger a DoS attack so it's a considered a security violation. If it's root only it doesn't matter. > > 3) Those weren't just tabs, those two lines were indented with all > spaces (oops), and thanks for taking out the cast if it is not needed. > > When there's too many arguments to type a whole function call > out on one line, though, I like to "stack" the arguments, it makes > it easier for me to see them... what do you think about that? Martin, > the other developer who does a lot of work on Orangefs, doesn't like > the way I put each argument on a line by itself, so maybe it is not > helpful to most people, or important... > The way I changed it is the normal way but few people one feel strongly about it. I just did that because I removed the unneeded casting (and forgot to mention it in the changelog). > 4) The preserved error code will find its way back to vfs through > file_operations->unlocked_ioctl in the context of the pseudo device > through which the kernel module and Orangefs' userspace communicate. It > could end up being EINVAL or ENOMEM. Is that OK? When Al was getting > after me for returning the wrong error codes, he said we shouldn't > pick ones that seem reasonable to us, rather we should pick from the ones > that POSIX said would be valid ones. I try to pick valid ones now by > looking at the associated syscall's man page. There's no ENOMEM in > the ioctl(2) man page. Preserving the error code is fine most of the time with a very few exceptions. -EIO was the wrong error code because that's for when you can't read/write to the hardware because a drive fails or something. regards, dan carpenter -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
