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This commit is contained in:
Andrey Skobtsov 2020-05-19 01:17:19 +03:00
parent b0a3dc2b88
commit 4103700aa6
2 changed files with 6 additions and 13 deletions
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6
src/Common/ThreadProfileEvents.cpp
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@ -182,6 +182,12 @@ static int openPerfEvent(perf_event_attr *hw_event, pid_t pid, int cpu, int grou
return static_cast<int>(syscall(SYS_perf_event_open, hw_event, pid, cpu, group_fd, flags));
}
// cat /proc/sys/kernel/perf_event_paranoid
// -1: Allow use of (almost) all events by all users
// >=0: Disallow raw tracepoint access by users without CAP_IOC_LOCK
// >=1: Disallow CPU event access by users without CAP_SYS_ADMIN
// >=2: Disallow kernel profiling by users without CAP_SYS_ADMIN
// >=3: Disallow all event access by users without CAP_SYS_ADMIN
static bool getPerfEventParanoid(Int32 & result)
{
// the longest possible variant: "-1\0"

13
src/Common/ThreadProfileEvents.h
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@ -185,19 +185,6 @@ struct PerfEventsCounters
// must be unsigned to not cause undefined behaviour on increment
typedef UInt64 Id;
// cat /proc/sys/kernel/perf_event_paranoid - if perf_event_paranoid is set to 3, all calls to `perf_event_open` are rejected (even for the current process)
// https://lwn.net/Articles/696234/
// -1: Allow use of (almost) all events by all users
// >=0: Disallow raw tracepoint access by users without CAP_IOC_LOCK
// >=1: Disallow CPU event access by users without CAP_SYS_ADMIN
// >=2: Disallow kernel profiling by users without CAP_SYS_ADMIN
// >=3: Disallow all event access by users without CAP_SYS_ADMIN
// https://lwn.net/Articles/696216/
// It adds a another value that can be set for the sysctl parameter (i.e. kernel.perf_event_paranoid=3)
// that restricts perf_event_open() to processes with the CAP_SYS_ADMIN capability
// todo: check whether perf_event_open() is available with CAP_SYS_ADMIN
static constexpr size_t NUMBER_OF_RAW_EVENTS = 18;
static const PerfEventInfo raw_events_info[PerfEventsCounters::NUMBER_OF_RAW_EVENTS];