path: root/lib/cpumask.c
diff options
authorRusty Russell <rusty@rustcorp.com.au>2009-01-01 10:12:30 +1030
committerRusty Russell <rusty@rustcorp.com.au>2009-01-01 10:12:30 +1030
commit2a53008033189ed09bfe241c6b33811ba4ce980d (patch)
tree86dcdacdd7fbaf671f2487b7a05352aa672fecc1 /lib/cpumask.c
parent5db0e1e9e0f30f160b832a0b5cd1131954bf4f6e (diff)
cpumask: zero extra bits in alloc_cpumask_var_node
Impact: extra safety checks during transition When CONFIG_CPUMASKS_OFFSTACK is set, the new cpumask_ operators only use bits up to nr_cpu_ids, not NR_CPUS. Using the old cpus_ operators on these masks can mean accessing undefined bits. After some discussion, Mike and I decided to err on the side of caution; we zero the "undefined" bits in alloc_cpumask_var_node() until all the old cpumask functions are removed. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'lib/cpumask.c')
1 files changed, 8 insertions, 0 deletions
diff --git a/lib/cpumask.c b/lib/cpumask.c
index 8e1496cb63f7..3389e2440da0 100644
--- a/lib/cpumask.c
+++ b/lib/cpumask.c
@@ -107,6 +107,14 @@ bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
+ /* FIXME: Bandaid to save us from old primitives which go to NR_CPUS. */
+ if (*mask) {
+ unsigned int tail;
+ tail = BITS_TO_LONGS(NR_CPUS - nr_cpumask_bits) * sizeof(long);
+ memset(cpumask_bits(*mask) + cpumask_size() - tail,
+ 0, tail);
+ }
return *mask != NULL;

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