Re: [PATCH] fanotify: fix -EOVERFLOW with large files on 64-bit

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On Thu, 2017-11-16 at 21:28 +0100, Greg KH wrote:
> On Thu, Nov 16, 2017 at 08:43:53PM +0100, Stefan Nuernberger wrote:
> > 
> > From: Will Woods <wwoods@xxxxxxxxxx>
> > 
> > commit 1e2ee49f7f1b79f0b14884fe6a602f0411b39552 upstream.
> > 
> > On 64-bit systems, O_LARGEFILE is automatically added to flags
> > inside
> > the open() syscall (also openat(), blkdev_open(), etc).  Userspace
> > therefore defines O_LARGEFILE to be 0 - you can use it, but it's a
> > no-op.  Everything should be O_LARGEFILE by default.
> > 
> > But: when fanotify does create_fd() it uses dentry_open(), which
> > skips
> > all that.  And userspace can't set O_LARGEFILE in fanotify_init()
> > because it's defined to 0.  So if fanotify gets an event regarding
> > a
> > large file, the read() will just fail with -EOVERFLOW.
> > 
> > This patch adds O_LARGEFILE to fanotify_init()'s event_f_flags on
> > 64-bit
> > systems, using the same test as open()/openat()/etc.
> > 
> > Addresses https://bugzilla.redhat.com/show_bug.cgi?id=696821
> > 
> > Signed-off-by: Will Woods <wwoods@xxxxxxxxxx>
> > Acked-by: Eric Paris <eparis@xxxxxxxxxx>
> > Reviewed-by: Jan Kara <jack@xxxxxxx>
> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> > 
> > [snu: Backported to 3.2 / 3.10: adjusted context]
> > 
> > Signed-off-by: Stefan Nuernberger <snu@xxxxxxxxxx>
> > Reviewed-by: Pawel Wieczorkiewicz <wipawel@xxxxxxxxx>
> > Reviewed-by: Simon Veith <sveith@xxxxxxxxx>
> > 
> > Cc: <stable@xxxxxxxxxxxxxxx> # 3.2.x and 3.10.x
> 3.10.y is end-of-life :(
> 
> See the front page of www.kernel.org for that list if you are
> curious.

Yes, I saw that. But as it still received an update earlier this month
I thought I just include it here. I'm happy if we can get this on the
3.2.y stable branch, though.

Thanks,
Stefan

> 
> thanks,
> 
> greg k-h
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