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tools/perf: Fix out of bound access to cpu mask array 

The cpu mask init code in "record__mmap_cpu_mask_init" function access
"bits" array part of "struct mmap_cpu_mask".  The size of this array is
the value from cpu__max_cpu().cpu.  This array 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 "bits" array.

If we provide a command line option to -C which is greater 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 record -C 12341234 ls
  Perf can support 2048 CPUs. Consider raising MAX_NR_CPUS
  Segmentation fault (core dumped)
<<>>

Debugging with gdb, points to function flow as below:

<<>>
  set_bit
  record__mmap_cpu_mask_init
  record__init_thread_default_masks
  record__init_thread_masks
  cmd_record
<<>>

Fix this by adding boundary check for the array.

After the patch:

<<>>
./perf record -C 12341234 ls
  Perf can support 2048 CPUs. Consider raising MAX_NR_CPUS
  Failed to initialize parallel data streaming masks
<<>>

With this fix, if -C is given a non-exsiting CPU, perf
record will fail with:

<<>>
  ./perf record -C 50 ls
  Failed to initialize parallel data streaming masks
<<>>

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/20220905141929.7171-2-atrajeev@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Athira Rajeev 2022-09-05 19:49:29 +05:30 committed by Arnaldo Carvalho de Melo
parent 72cd652b73
commit cbd7bfc7fd
1 changed files with 20 additions and 6 deletions
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26
tools/perf/builtin-record.c
View File

@ -3358,16 +3358,22 @@ static struct option __record_options[] = {
struct option *record_options = __record_options;
static void record__mmap_cpu_mask_init(struct mmap_cpu_mask *mask, struct perf_cpu_map *cpus)
static int record__mmap_cpu_mask_init(struct mmap_cpu_mask *mask, struct perf_cpu_map *cpus)
{
struct perf_cpu cpu;
int idx;
if (cpu_map__is_dummy(cpus))
return;
return 0;
perf_cpu_map__for_each_cpu(cpu, idx, cpus)
perf_cpu_map__for_each_cpu(cpu, idx, cpus) {
/* Return ENODEV is input cpu is greater than max cpu */
if ((unsigned long)cpu.cpu > mask->nbits)
return -ENODEV;
set_bit(cpu.cpu, mask->bits);
}
return 0;
}
static int record__mmap_cpu_mask_init_spec(struct mmap_cpu_mask *mask, const char *mask_spec)
@ -3379,7 +3385,9 @@ static int record__mmap_cpu_mask_init_spec(struct mmap_cpu_mask *mask, const cha
return -ENOMEM;
bitmap_zero(mask->bits, mask->nbits);
record__mmap_cpu_mask_init(mask, cpus);
if (record__mmap_cpu_mask_init(mask, cpus))
return -ENODEV;
perf_cpu_map__put(cpus);
return 0;
@ -3461,7 +3469,12 @@ static int record__init_thread_masks_spec(struct record *rec, struct perf_cpu_ma
pr_err("Failed to allocate CPUs mask\n");
return ret;
}
record__mmap_cpu_mask_init(&cpus_mask, cpus);
ret = record__mmap_cpu_mask_init(&cpus_mask, cpus);
if (ret) {
pr_err("Failed to init cpu mask\n");
goto out_free_cpu_mask;
}
ret = record__thread_mask_alloc(&full_mask, cpu__max_cpu().cpu);
if (ret) {
@ -3702,7 +3715,8 @@ static int record__init_thread_default_masks(struct record *rec, struct perf_cpu
if (ret)
return ret;
record__mmap_cpu_mask_init(&rec->thread_masks->maps, cpus);
if (record__mmap_cpu_mask_init(&rec->thread_masks->maps, cpus))
return -ENODEV;
rec->nr_threads = 1;