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| author | Chris Metcalf <cmetcalf@ezchip.com> | 2015-06-25 15:02:08 -0700 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2015-08-04 16:52:29 +0200 |
| commit | 75ad64dc348105bdf1c19b92566a224e9f87883b (patch) | |
| tree | b83e09076ee900c9c17ac77d6edb5bffe681a4de | |
| parent | f21dad05bb0219480fad3c4873fec923023431e4 (diff) | |
| download | lwn-75ad64dc348105bdf1c19b92566a224e9f87883b.tar.gz lwn-75ad64dc348105bdf1c19b92566a224e9f87883b.zip | |
__bitmap_parselist: fix bug in empty string handling
commit 2528a8b8f457d7432552d0e2b6f0f4046bb702f4 upstream.
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>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
| -rw-r--r-- | lib/bitmap.c | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/lib/bitmap.c b/lib/bitmap.c index e5c4ebe586ba..c0634aa923a6 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -603,12 +603,12 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen, unsigned a, b; int c, old_c, totaldigits; const char __user __force *ubuf = (const char __user __force *)buf; - int exp_digit, in_range; + int at_start, in_range; totaldigits = c = 0; bitmap_zero(maskp, nmaskbits); do { - exp_digit = 1; + at_start = 1; in_range = 0; a = b = 0; @@ -637,11 +637,10 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen, break; if (c == '-') { - if (exp_digit || in_range) + if (at_start || in_range) return -EINVAL; b = 0; in_range = 1; - exp_digit = 1; continue; } @@ -651,16 +650,18 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen, b = b * 10 + (c - '0'); if (!in_range) a = b; - exp_digit = 0; + at_start = 0; totaldigits++; } if (!(a <= b)) return -EINVAL; if (b >= nmaskbits) return -ERANGE; - while (a <= b) { - set_bit(a, maskp); - a++; + if (!at_start) { + while (a <= b) { + set_bit(a, maskp); + a++; + } } } while (buflen && c == ','); return 0; |