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[v3,0/1] coresight: tmc: Explicit type conversions to

Message ID 20230804081514.120171-1-tianruidong@linux.alibaba.com (mailing list archive)
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Series coresight: tmc: Explicit type conversions to | expand

Message

Ruidong Tian Aug. 4, 2023, 8:15 a.m. UTC 
Perf cs_etm session executed unexpectedly when AUX buffer > 1G.

  perf record -C 0 -m ,2G -e cs_etm// -- <workload>
  [ perf record: Captured and wrote 2.615 MB perf.data ]

Perf only collect about 2M perf data rather than 2G. This is becasuse
the operation, "nr_pages << PAGE_SHIFT", in coresight tmc driver, will
overflow when nr_pages >= 0x80000(correspond to 1G AUX buffer). The
overflow cause buffer allocation to fail, and TMC driver will alloc
minimal buffer size(1M). You can just get about 2M perf data(1M AUX
buffer + perf data header) at least.

Explicit convert nr_pages to 64 bit in tmc driver to avoid overflow.

Changes in V2:
Suzuki K Poulose:
    Add another 2 places where needed to fix.

Changes in V1:
James Clark:
    Use a more accurate commit message.

Ruidong Tian (1):
  coresight: tmc: Explicit type conversions to prevent integer overflow

 drivers/hwtracing/coresight/coresight-tmc-etf.c | 2 +-
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 5 +++--
 drivers/hwtracing/coresight/coresight-tmc.h     | 2 +-
 3 files changed, 5 insertions(+), 4 deletions(-)