[PATCH v2 0/2] cpufreq: acpi-cpufreq: fix P-state index mismatch in freq lookups

[lirongqing]

From: Li RongQing <lirongqing@xxxxxxxxx>

policy->freq_table is built with duplicate _PSS frequencies dropped, so it
no longer lines up positionally with perf->states[]; the original P-state
index is kept in freq_table[].driver_data. extract_io() and
get_cur_freq_on_cpu() indexed freq_table[] with a perf->states[] index
anyway, which can return the frequency of a wrong P-state.

Changes since v1:
- Reword patch 1: v1 described it as an out-of-bounds read, which is wrong;
  it is an index-mismatch / wrong-result bug, not a memory-safety issue.
- Add patch 2 for get_cur_freq_on_cpu().
- Add Fixes: tags (not exact, but reasonable backport targets).

Li RongQing (2):
  cpufreq: acpi-cpufreq: fix P-state index mismatch in extract_io()
  cpufreq: acpi-cpufreq: fix P-state index mismatch in
    get_cur_freq_on_cpu()

 drivers/cpufreq/acpi-cpufreq.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

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2.9.4