From: "H. Peter Anvin" <hpa@zytor•com>
To: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom•com>
Cc: Linux/PPC Development <linuxppc-dev@ozlabs•org>,
Linux Kernel Development <linux-kernel@vger•kernel.org>,
Hiroaki Fuse <Hiroaki_Fuse@hq•scei.sony.co.jp>
Subject: Re: Too verbose compat_ioctl messages?
Date: Fri, 06 Jul 2007 09:30:43 -0700 [thread overview]
Message-ID: <468E6E33.3040000@zytor.com> (raw)
In-Reply-To: <Pine.LNX.4.62.0707061431360.1203@pademelon.sonytel.be>
Geert Uytterhoeven wrote:
>
> Fuse-san discovered that running the umount that's part of busybox on a PS3
> with a recent kernel causes an error message to be printed on the console:
>
> | ioctl32(busybox:1340): Unknown cmd fd(3) cmd(00004c01){t:'L';sz:0} arg(00000000) on /dev/sda1
>
> On older kernels (e.g. 2.6.16), this doesn't happen.
>
> It can easily be reproduced by installing busybox and running
>
> | busybox umount /mountpoint
>
> on a mounted filesystem (except when using the loop device).
>
> Apparently Busybox uses the LOOP_CLR_FD ioctl when unmounting a file system,
> which is supported by the loop device only.
> On other block device types, this ioctl is not supported:
> - With a 64-bit application, the block layer returns ENOTTY (Inappropriate
> ioctl for device), while the SCSI layer returns EINVAL (Invalid argument)
> - With a 32-bit application, the compat_ioctl code returns EINVAL (Invalid
> argument) and prints an error on the console (for the first 50
> occurrencies, cfr. fs/compat_ioctl.c:compat_sys_ioctl())
>
> As I understand, compat_ioctl_error() is used to inform the user about ioctl
> values that are not yet handled by the compat_ioctl layer. However, LOOP_CLR_FD
> doesn't need to be handled (no data to convert between 32-bit and 64-bit), and
> it's perfectly valid for a block device to not implement it.
> So it's confusing to print this error message.
>
> Is there anything we can do about this?
>
For one thing, it looks like we're returning the wrong thing (EINVAL
rather than ENOTTY) across the board. This was unfortunately a common
misunderstanding with non-tty-related ioctls in the early days of Linux.
-hpa
next prev parent reply other threads:[~2007-07-06 17:04 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-06 12:47 Too verbose compat_ioctl messages? Geert Uytterhoeven
2007-07-06 12:57 ` Andreas Schwab
2007-07-06 15:49 ` Geert Uytterhoeven
2007-07-06 15:52 ` [PATCH] compat32: ignore the LOOP_CLR_FD ioctl Geert Uytterhoeven
2007-07-06 16:30 ` H. Peter Anvin [this message]
2007-07-06 18:14 ` Too verbose compat_ioctl messages? Andi Kleen
2007-07-06 17:48 ` H. Peter Anvin
2007-07-06 18:33 ` Jeremy Fitzhardinge
2007-07-06 18:36 ` H. Peter Anvin
2007-07-06 18:40 ` Jeremy Fitzhardinge
2007-07-06 19:04 ` Andi Kleen
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