__bitmap_parselist: fix bug in empty string handling
authorChris Metcalf <cmetcalf@ezchip.com>
Thu, 25 Jun 2015 22:02:08 +0000 (15:02 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 26 Jun 2015 00:00:40 +0000 (17:00 -0700)
commit2528a8b8f457d7432552d0e2b6f0f4046bb702f4
treea9656e593920e8cceabca160046c9ab65d7456a0
parent4f973c63d158b9293f7dc16f54e119d75bc20380
__bitmap_parselist: fix bug in empty string handling

bitmap_parselist("", &mask, nmaskbits) will erroneously set bit zero in
the mask.  The same bug is visible in cpumask_parselist() since it is
layered on top of the bitmask code, e.g.  if you boot with "isolcpus=",
you will actually end up with cpu zero isolated.

The bug was introduced in commit 4b060420a596 ("bitmap, irq: add
smp_affinity_list interface to /proc/irq") when bitmap_parselist() was
generalized to support userspace as well as kernelspace.

Fixes: 4b060420a596 ("bitmap, irq: add smp_affinity_list interface to /proc/irq")
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
lib/bitmap.c