[PATCH v1 0/2] perf: Drop leaked kernel samples
From: Jin Yao
Date: Thu Jun 14 2018 - 22:10:05 EST
On workloads that do a lot of kernel entry/exits we see kernel
samples, even though :u is specified. This is due to skid existing.
This might be a security issue because it can leak kernel addresses even
though kernel sampling support is disabled.
One patch "perf/core: Drop kernel samples even though :u is specified"
was posted in last year but it was reverted because it introduced a
regression issue that broke the rr-project.
Now this patch set uses sysctl to control the dropping of leaked
kernel samples.
/sys/devices/cpu/perf_allow_sample_leakage:
0 - default, drop the leaked kernel samples.
1 - don't drop the leaked kernel samples.
For rr it can write 1 to /sys/devices/cpu/perf_allow_sample_leakage to
keep original system behavior.
Jin Yao (2):
perf/core: Use sysctl to turn on/off dropping leaked kernel samples
perf Documentation: Introduce the sysctl perf_allow_sample_leakage
kernel/events/core.c | 58 ++++++++++++++++++++++++++++++++
tools/perf/Documentation/perf-record.txt | 14 ++++++++
2 files changed, 72 insertions(+)
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2.7.4