From 2a53008033189ed09bfe241c6b33811ba4ce980d Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Thu, 1 Jan 2009 10:12:30 +1030 Subject: 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 --- lib/cpumask.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'lib') 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) dump_stack(); } #endif + /* 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; } EXPORT_SYMBOL(alloc_cpumask_var_node); -- cgit v1.2.3-59-g8ed1b