Yury Norov a333a284ff lib: fix stall in __bitmap_parselist()
commit 8351760ff5b2042039554b4948ddabaac644a976 upstream.

syzbot is catching stalls at __bitmap_parselist()
(https://syzkaller.appspot.com/bug?id=ad7e0351fbc90535558514a71cd3edc11681997a).
The trigger is

  unsigned long v = 0;
  bitmap_parselist("7:,", &v, BITS_PER_LONG);

which results in hitting infinite loop at

    while (a <= b) {
	    off = min(b - a + 1, used_size);
	    bitmap_set(maskp, a, off);
	    a += group_size;
    }

due to used_size == group_size == 0.

Link: http://lkml.kernel.org/r/20180404162647.15763-1-ynorov@caviumnetworks.com
Fixes: 0a5ce0831d04382a ("lib/bitmap.c: make bitmap_parselist() thread-safe and much faster")
Signed-off-by: Yury Norov <ynorov@caviumnetworks.com>
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+6887cbb011c8054e8a3d@syzkaller.appspotmail.com>
Cc: Noam Camus <noamca@mellanox.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-19 08:56:20 +02:00
..
2018-03-03 10:24:29 +01:00
2017-08-15 09:02:08 -07:00
2015-11-23 09:44:58 +01:00
2017-06-09 11:52:07 +02:00
2017-02-24 17:46:57 -08:00
2017-05-09 15:40:28 -07:00
2017-02-24 17:46:57 -08:00
2017-10-03 17:54:25 -07:00
2018-02-22 15:42:24 +01:00
2018-02-16 20:23:04 +01:00
2016-12-06 10:17:03 +02:00
2015-09-08 14:35:59 -07:00
2017-07-07 10:37:54 -07:00
2017-08-15 09:02:07 -07:00