Extend error messages to mention CAP_PERFMON capability as an option to
substitute CAP_SYS_ADMIN capability for secure system performance
monitoring and observability operations. Make
perf_event_paranoid_check() and __cmd_ftrace() to be aware of
CAP_PERFMON capability.
CAP_PERFMON implements the principle of least privilege for performance
monitoring and observability operations (POSIX IEEE 1003.1e 2.2.2.39
principle of least privilege: A security design principle that states
that a process or program be granted only those privileges (e.g.,
capabilities) necessary to accomplish its legitimate function, and only
for the time that such privileges are actually required)
For backward compatibility reasons access to perf_events subsystem remains
open for CAP_SYS_ADMIN privileged processes but CAP_SYS_ADMIN usage for
secure perf_events monitoring is discouraged with respect to CAP_PERFMON
capability.
Committer testing:
Using a libcap with this patch:
diff --git a/libcap/include/uapi/linux/capability.h b/libcap/include/uapi/linux/capability.h
index 78b2fd4c8a95..89b5b0279b60 100644
--- a/libcap/include/uapi/linux/capability.h
+++ b/libcap/include/uapi/linux/capability.h
@@ -366,8 +366,9 @@ struct vfs_ns_cap_data {
#define CAP_AUDIT_READ 37
+#define CAP_PERFMON 38
-#define CAP_LAST_CAP CAP_AUDIT_READ
+#define CAP_LAST_CAP CAP_PERFMON
#define cap_valid(x) ((x) >= 0 && (x) <= CAP_LAST_CAP)
Note that using '38' in place of 'cap_perfmon' works to some degree with
an old libcap, its only when cap_get_flag() is called that libcap
performs an error check based on the maximum value known for
capabilities that it will fail.
This makes determining the default of perf_event_attr.exclude_kernel to
fail, as it can't determine if CAP_PERFMON is in place.
Using 'perf top -e cycles' avoids the default check and sets
perf_event_attr.exclude_kernel to 1.
As root, with a libcap supporting CAP_PERFMON:
# groupadd perf_users
# adduser perf -g perf_users
# mkdir ~perf/bin
# cp ~acme/bin/perf ~perf/bin/
# chgrp perf_users ~perf/bin/perf
# setcap "cap_perfmon,cap_sys_ptrace,cap_syslog=ep" ~perf/bin/perf
# getcap ~perf/bin/perf
/home/perf/bin/perf = cap_sys_ptrace,cap_syslog,cap_perfmon+ep
# ls -la ~perf/bin/perf
-rwxr-xr-x. 1 root perf_users 16968552 Apr 9 13:10 /home/perf/bin/perf
As the 'perf' user in the 'perf_users' group:
$ perf top -a --stdio
Error:
Failed to mmap with 1 (Operation not permitted)
$
Either add the cap_ipc_lock capability to the perf binary or reduce the
ring buffer size to some smaller value:
$ perf top -m10 -a --stdio
rounding mmap pages size to 64K (16 pages)
Error:
Failed to mmap with 1 (Operation not permitted)
$ perf top -m4 -a --stdio
Error:
Failed to mmap with 1 (Operation not permitted)
$ perf top -m2 -a --stdio
PerfTop: 762 irqs/sec kernel:49.7% exact: 100.0% lost: 0/0 drop: 0/0 [4000Hz cycles], (all, 4 CPUs)
------------------------------------------------------------------------------------------------------
9.83% perf [.] __symbols__insert
8.58% perf [.] rb_next
5.91% [kernel] [k] module_get_kallsym
5.66% [kernel] [k] kallsyms_expand_symbol.constprop.0
3.98% libc-2.29.so [.] __GI_____strtoull_l_internal
3.66% perf [.] rb_insert_color
2.34% [kernel] [k] vsnprintf
2.30% [kernel] [k] string_nocheck
2.16% libc-2.29.so [.] _IO_getdelim
2.15% [kernel] [k] number
2.13% [kernel] [k] format_decode
1.58% libc-2.29.so [.] _IO_feof
1.52% libc-2.29.so [.] __strcmp_avx2
1.50% perf [.] rb_set_parent_color
1.47% libc-2.29.so [.] __libc_calloc
1.24% [kernel] [k] do_syscall_64
1.17% [kernel] [k] __x86_indirect_thunk_rax
$ perf record -a sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.552 MB perf.data (74 samples) ]
$ perf evlist
cycles
$ perf evlist -v
cycles: size: 120, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CPU|PERIOD, read_format: ID, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, task: 1, precise_ip: 3, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1
$ perf report | head -20
# To display the perf.data header info, please use --header/--header-only options.
#
#
# Total Lost Samples: 0
#
# Samples: 74 of event 'cycles'
# Event count (approx.): 15694834
#
# Overhead Command Shared Object Symbol
# ........ ............... .......................... ......................................
#
19.62% perf [kernel.vmlinux] [k] strnlen_user
13.88% swapper [kernel.vmlinux] [k] intel_idle
13.83% ksoftirqd/0 [kernel.vmlinux] [k] pfifo_fast_dequeue
13.51% swapper [kernel.vmlinux] [k] kmem_cache_free
6.31% gnome-shell [kernel.vmlinux] [k] kmem_cache_free
5.66% kworker/u8:3+ix [kernel.vmlinux] [k] delay_tsc
4.42% perf [kernel.vmlinux] [k] __set_cpus_allowed_ptr
3.45% kworker/2:1-eve [kernel.vmlinux] [k] shmem_truncate_range
2.29% gnome-shell libgobject-2.0.so.0.6000.7 [.] g_closure_ref
$
Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Igor Lubashev <ilubashe@akamai.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: intel-gfx@lists.freedesktop.org
Cc: linux-doc@vger.kernel.org
Cc: linux-man@vger.kernel.org
Cc: linux-security-module@vger.kernel.org
Cc: selinux@vger.kernel.org
Link: http://lore.kernel.org/lkml/a66d5648-2b8e-577e-e1f2-1d56c017ab5e@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Update the names of some functions and enums in design.txt. The document
still has some stale information, but the motivation behind this patch
is to allow a developer to quickly grep and learn about the associated
structures.
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1395169804-1293-1-git-send-email-artagnon@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The ioctl interface of perf event fd receives 3 arguments to control
event group behavior but it lacked documentation.
Signed-off-by: Namhyung Kim <namhyung.kim@lge.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1338443506-25009-2-git-send-email-namhyung.kim@lge.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
perf_event_hw_event has been renamed to perf_event_attr. The
design document was still using the old name, though.
Signed-off-by: Tim Blechmann <tim@klingt.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4B37646A.90108@klingt.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Add two more software events that are common to many cpus.
Alignment faults: When a load or store is not aligned properly.
Emulation faults: When an instruction is emulated in software.
Both cause a very significant slowdown (100x or worse), so identifying and
fixing them is very important.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Some architectures such as Sparc, ARM and MIPS (basically
everything with flush_dcache_page()) need to deal with dcache
aliases by carefully placing pages in both kernel and user maps.
These architectures typically have to use vmalloc_user() for this.
However, on other architectures, vmalloc() is not needed and has
the downsides of being more restricted and slower than regular
allocations.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: David Miller <davem@davemloft.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1254830228.21044.272.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Bye-bye Performance Counters, welcome Performance Events!
In the past few months the perfcounters subsystem has grown out its
initial role of counting hardware events, and has become (and is
becoming) a much broader generic event enumeration, reporting, logging,
monitoring, analysis facility.
Naming its core object 'perf_counter' and naming the subsystem
'perfcounters' has become more and more of a misnomer. With pending
code like hw-breakpoints support the 'counter' name is less and
less appropriate.
All in one, we've decided to rename the subsystem to 'performance
events' and to propagate this rename through all fields, variables
and API names. (in an ABI compatible fashion)
The word 'event' is also a bit shorter than 'counter' - which makes
it slightly more convenient to write/handle as well.
Thanks goes to Stephane Eranian who first observed this misnomer and
suggested a rename.
User-space tooling and ABI compatibility is not affected - this patch
should be function-invariant. (Also, defconfigs were not touched to
keep the size down.)
This patch has been generated via the following script:
FILES=$(find * -type f | grep -vE 'oprofile|[^K]config')
sed -i \
-e 's/PERF_EVENT_/PERF_RECORD_/g' \
-e 's/PERF_COUNTER/PERF_EVENT/g' \
-e 's/perf_counter/perf_event/g' \
-e 's/nb_counters/nb_events/g' \
-e 's/swcounter/swevent/g' \
-e 's/tpcounter_event/tp_event/g' \
$FILES
for N in $(find . -name perf_counter.[ch]); do
M=$(echo $N | sed 's/perf_counter/perf_event/g')
mv $N $M
done
FILES=$(find . -name perf_event.*)
sed -i \
-e 's/COUNTER_MASK/REG_MASK/g' \
-e 's/COUNTER/EVENT/g' \
-e 's/\<event\>/event_id/g' \
-e 's/counter/event/g' \
-e 's/Counter/Event/g' \
$FILES
... to keep it as correct as possible. This script can also be
used by anyone who has pending perfcounters patches - it converts
a Linux kernel tree over to the new naming. We tried to time this
change to the point in time where the amount of pending patches
is the smallest: the end of the merge window.
Namespace clashes were fixed up in a preparatory patch - and some
stylistic fallout will be fixed up in a subsequent patch.
( NOTE: 'counters' are still the proper terminology when we deal
with hardware registers - and these sed scripts are a bit
over-eager in renaming them. I've undone some of that, but
in case there's something left where 'counter' would be
better than 'event' we can undo that on an individual basis
instead of touching an otherwise nicely automated patch. )
Suggested-by: Stephane Eranian <eranian@google.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Paul Mackerras <paulus@samba.org>
Reviewed-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <linux-arch@vger.kernel.org>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Help out arch porters who want to support perf counters by listing some
basic requirements.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1244827063-24046-1-git-send-email-vapier@gentoo.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Pure renames only, to PERF_COUNT_HW_* and PERF_COUNT_SW_*.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Several people have suggested that 'perf' has become a full-fledged
tool that should be moved out of Documentation/. Move it to the
(new) tools/ directory.
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
