From: Dmitry Monakhov <dmonakhov@openvz.org>
Date: Tue, 10 Feb 2015 22:09:29 +0000 (-0800)
Subject: fsioctl.c: make generic_block_fiemap() signal-tolerant
X-Git-Tag: fixes-v4.0-rc1~155^2~51
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=913e027ca17ee06fa9436a21e54464795b0fa0e8;p=pandora-kernel.git

fsioctl.c: make generic_block_fiemap() signal-tolerant

__generic_block_fiemap may spin very long time for large sparse files.

Without this patch an unprivileged user may abuse system resources simply
by spawning a vast number of unkilable busyloops (works on ext2/ext3):

  truncate --size 1T test
  for ((i=0;i<1024;i++))
  do
         filefrag test > /dev/null &
  done

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

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