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authorHeiko Carstens <heiko.carstens@de.ibm.com>2015-02-09 06:54:16 -0500
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2015-02-10 04:15:57 -0500
commit45cce4ccafe3cddc924ef5221d22b9853fc9a13c (patch)
tree3afaaeec8ecc47be92aa209b715c84522ff9c1f5
parentea96f78813823ab186e7e52122c06fb9c3cf6e20 (diff)
s390/cacheinfo: don't use smp_processor_id() in preemptible context
show_cacheinfo() needs to access the cacheinfo structure of any online cpu. This was done with using smp_processor_id() as in index while in preemtible context. This means the cpu could be offline and the data be gone when it would be accessed. Better use any online cpu address and protect the data by get_online_cpus() and put_online_cpus(). Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
-rw-r--r--arch/s390/kernel/cache.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/s390/kernel/cache.c b/arch/s390/kernel/cache.c
index fe21f074cf9f..632fa06ea162 100644
--- a/arch/s390/kernel/cache.c
+++ b/arch/s390/kernel/cache.c
@@ -66,10 +66,12 @@ static const enum cache_type cache_type_map[] = {
66 66
67void show_cacheinfo(struct seq_file *m) 67void show_cacheinfo(struct seq_file *m)
68{ 68{
69 int cpu = smp_processor_id(), idx; 69 struct cpu_cacheinfo *this_cpu_ci;
70 struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
71 struct cacheinfo *cache; 70 struct cacheinfo *cache;
71 int idx;
72 72
73 get_online_cpus();
74 this_cpu_ci = get_cpu_cacheinfo(cpumask_any(cpu_online_mask));
73 for (idx = 0; idx < this_cpu_ci->num_leaves; idx++) { 75 for (idx = 0; idx < this_cpu_ci->num_leaves; idx++) {
74 cache = this_cpu_ci->info_list + idx; 76 cache = this_cpu_ci->info_list + idx;
75 seq_printf(m, "cache%-11d: ", idx); 77 seq_printf(m, "cache%-11d: ", idx);
@@ -82,6 +84,7 @@ void show_cacheinfo(struct seq_file *m)
82 seq_printf(m, "associativity=%d", cache->ways_of_associativity); 84 seq_printf(m, "associativity=%d", cache->ways_of_associativity);
83 seq_puts(m, "\n"); 85 seq_puts(m, "\n");
84 } 86 }
87 put_online_cpus();
85} 88}
86 89
87static inline enum cache_type get_cache_type(struct cache_info *ci, int level) 90static inline enum cache_type get_cache_type(struct cache_info *ci, int level)