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Message-Id: <20141218151247.b6ccd73351f40db66818c07e@linux-foundation.org>
Date: Thu, 18 Dec 2014 15:12:47 -0800
From: Andrew Morton <akpm@...ux-foundation.org>
To: Dmitry Monakhov <dmonakhov@...nvz.org>
Cc: linux-kernel@...r.kernel.org,
ext4 development <linux-ext4@...r.kernel.org>,
"Theodore Ts'o" <tytso@....edu>, Al Viro <viro@...IV.linux.org.uk>,
Michael Kerrisk <mtk.manpages@...il.com>
Subject: Re: [PATCH] fs: make generic_block_fiemap sig-tolerant PING2...
On Wed, 10 Dec 2014 16:49:18 +0300 Dmitry Monakhov <dmonakhov@...nvz.org> wrote:
>
> Hello. Someone please take care of this patch.
>
> W/o that patch unprivileged user may abuse system resources simply by spawning
> wast number of unkilable busyloops (works on ext2/ext3):
>
> truncate --size 1T test
> for ((i=0;i<1024;i++))
> do
> filefrag test > /dev/null &
> done
>
> >> --- a/fs/ioctl.c
> >> +++ b/fs/ioctl.c
> >> @@ -379,6 +379,11 @@ int __generic_block_fiemap(struct inode *inode,
> >> past_eof = true;
> >> }
> >> cond_resched();
> >> + if (fatal_signal_pending(current)) {
> >> + ret = -EINTR;
> >> + break;
> >> + }
> >> +
> >> } while (1);
> >>
Is FIEMAP documented anywhere (manpage)? If so, that will need an
update.
--
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