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 <[email protected]>
Signed-off-by: Athira Jajeev <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Tested-by: Nageswara R Sastry <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kajol Jain <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

0 files changed, 0 insertions, 0 deletions