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authorAthira Rajeev <atrajeev@linux.vnet.ibm.com>2022-09-05 17:19:28 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2022-09-06 15:45:23 +0300
commit72cd652b73dd77df6f26bd450e804ee29232669f (patch)
treebb3b0a4d54b2f99b2299fc491f7ef967c1593bcd /tools
parentf0c86a2bae4fd12bfa8bad4d43fb59fb498cdd14 (diff)
downloadlinux-72cd652b73dd77df6f26bd450e804ee29232669f.tar.xz
perf affinity: Fix out of bound access to "sched_cpus" mask
The affinity code in "affinity_set" function access array named "sched_cpus". The size for this array is allocated in affinity_setup function which is nothing but value from get_cpu_set_size. This is used to contain the cpumask value for each cpu. While setting bit for each cpu, it calls "set_bit" function which access index in sched_cpus array. If we provide a command-line option to -C which is more than the number of CPU's present in the system, the set_bit could access an array member which is out-of the array size. This is because currently, there is no boundary check for the CPU. This will result in seg fault: <<>> ./perf stat -C 12323431 ls Perf can support 2048 CPUs. Consider raising MAX_NR_CPUS Segmentation fault (core dumped) <<>> Fix this by adding boundary check for the array. After the fix from powerpc system: <<>> ./perf stat -C 12323431 ls 1>out Perf can support 2048 CPUs. Consider raising MAX_NR_CPUS Performance counter stats for 'CPU(s) 12323431': <not supported> msec cpu-clock <not supported> context-switches <not supported> cpu-migrations <not supported> page-faults <not supported> cycles <not supported> instructions <not supported> branches <not supported> branch-misses 0.001192373 seconds time elapsed <<>> Reported-by: Nageswara R Sastry <rnsastry@linux.ibm.com> Signed-off-by: Athira Jajeev <atrajeev@linux.vnet.ibm.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Tested-by: Nageswara R Sastry <rnsastry@linux.ibm.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kajol Jain <kjain@linux.ibm.com> Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: linuxppc-dev@lists.ozlabs.org Link: https://lore.kernel.org/r/20220905141929.7171-1-atrajeev@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
-rw-r--r--tools/perf/util/affinity.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/tools/perf/util/affinity.c b/tools/perf/util/affinity.c
index 4d216c0dc425..4ee96b3c755b 100644
--- a/tools/perf/util/affinity.c
+++ b/tools/perf/util/affinity.c
@@ -49,8 +49,14 @@ void affinity__set(struct affinity *a, int cpu)
{
int cpu_set_size = get_cpu_set_size();
- if (cpu == -1)
+ /*
+ * Return:
+ * - if cpu is -1
+ * - restrict out of bound access to sched_cpus
+ */
+ if (cpu == -1 || ((cpu >= (cpu_set_size * 8))))
return;
+
a->changed = true;
set_bit(cpu, a->sched_cpus);
/*