perf tools: Fix int16_t truncation of max_cpu_num in set_max_cpu_num()

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set_max_cpu_num() assigns the sysfs "possible" CPU count to
max_cpu_num.cpu which is int16_t (struct perf_cpu).  On systems
with >32767 possible CPUs the value silently truncates, potentially
wrapping negative.  This causes cpunode_map to be underallocated
and subsequent cpu__get_node() calls to read out of bounds.

The matching check for max_present_cpu_num was added by commit
c760174401 ("perf cpumap: Reduce cpu size from int to int16_t")
but max_cpu_num was missed.  Add the same INT16_MAX guard.

Fixes: c760174401 ("perf cpumap: Reduce cpu size from int to int16_t")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

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This commit is contained in:

Arnaldo Carvalho de Melo 2026-06-06 11:25:40 -03:00

parent e2496db45b

commit 33fa2bf560

1 changed files with 17 additions and 4 deletions

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tools/perf/util/cpumap.c

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