diff options
| author | Athira Rajeev <atrajeev@linux.vnet.ibm.com> | 2022-09-05 19:49:28 +0530 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2022-09-06 09:45:23 -0300 |
| commit | 72cd652b73dd77df6f26bd450e804ee29232669f (patch) | |
| tree | bb3b0a4d54b2f99b2299fc491f7ef967c1593bcd /tools/perf | |
| parent | f0c86a2bae4fd12bfa8bad4d43fb59fb498cdd14 (diff) | |
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/perf')
| -rw-r--r-- | tools/perf/util/affinity.c | 8 |
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); /* |