perf record: Skip affinity for per-thread mmap buffers

Per-thread mmap buffers use CPU -1 to mean any CPU. Combining --per-thread
with --affinity=cpu passes this value to __set_bit() when constructing the
reader affinity mask, causing an out-of-bounds bitmap access and SIGSEGV.

Program received signal SIGSEGV, Segmentation fault.
0x0000555555f3488e in mmap.mmap ()
#0  0x0000555555f3488e in mmap.mmap ()
#1  0x0000555555e2f7bf in mmap_per_evsel (evlist=evlist@entry=0x7fffedcc1150, ops=ops@entry=0x7fffffffaf50, idx=idx@entry=0, mp=mp@entry=0x7fffffffaf70, cpu_idx=cpu_idx@entry=0, thread=thread@entry=0, _output=0x7fffffffaf08, _output_overwrite=0x7fffffffaf04, nr_mmaps=0x7fffffffaf0c) at evlist.c:598
#2  0x0000555555e2ef96 in mmap_per_thread (evlist=0x7fffedcc1150, ops=0x7fffffffaf50, mp=0x7fffffffaf70) at evlist.c:650
#3  perf_evlist__mmap_ops (evlist=0x7fffedcc1150, ops=0x7fffffffaf50, mp=0x7fffffffaf70) at evlist.c:748
#4  0x0000555555f2150d in evlist.mmap_ex ()
#5  0x0000555555db0b0a in record.open ()
#6  0x0000555555dadea7 in __cmd_record ()
#7  0x0000555555daca89 in cmd_record ()
#8  0x0000555555e27d53 in run_builtin ()
#9  0x0000555555e277cf in main ()
rip            0x555555f3488e      0x555555f3488e <mmap.mmap+382>
rax            0x7fffef9e9bd0      140737213537232
rbx            0x7fffedd249a0      140737183369632
rcx            0x3ffffffffffffff   288230376151711743
rdx            0x8000000000000000  -9223372036854775808
rsi            0x0                 0
rdi            0x7fffef9e9bd0      140737213537232
   0x555555f34876 <mmap__mmap+358>:	movswq 0x10(%rbx),%rcx
   0x555555f3487b <mmap__mmap+363>:	mov    0xb8(%rbx),%rax
   0x555555f34882 <mmap__mmap+370>:	mov    $0x1,%edx
   0x555555f34887 <mmap__mmap+375>:	shl    %cl,%rdx
   0x555555f3488a <mmap__mmap+378>:	shr    $0x6,%rcx
=> 0x555555f3488e <mmap__mmap+382>:	or     %rdx,(%rax,%rcx,8)
   0x555555f34892 <mmap__mmap+386>:	lea    0x17711b(%rip),%r14        # 0x5555560ab9b4 <verbose>
   0x555555f34899 <mmap__mmap+393>:	cmpl   $0x2,(%r14)
   0x555555f3489d <mmap__mmap+397>:	jne    0x555555f348f7 <mmap__mmap+487>
   0x555555f3489f <mmap__mmap+399>:	mov    0xb8(%rbx),%rdi
   0x555555f348a6 <mmap__mmap+406>:	mov    0xc0(%rbx),%esi
   0x555555f348ac <mmap__mmap+412>:	lea    -0x430(%rbp),%r12

Only construct and apply reader affinity masks for buffers with a
nonnegative CPU. Skip the reader-side bitmap operations as well, since
per-thread buffers no longer allocate an affinity mask.

Fixes: 8384a2600c7ddfc8 ("perf record: Adapt affinity to machines with #CPUs > 1K")
Signed-off-by: Paul Moses <p@1g4.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>