kernel/linux.git/tools/perf/util/util.c, branch v5.9.2

perf tools: Support CAP_PERFMON capability

2020-04-16T15:19:08+00:00

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 Reviewed-by: James Morris Acked-by: Jiri Olsa Acked-by: Namhyung Kim Tested-by: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov Cc: Andi Kleen Cc: Igor Lubashev Cc: Peter Zijlstra Cc: Serge Hallyn Cc: Song Liu Cc: Stephane Eranian Cc: Thomas Gleixner 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

perf util: Factor out sysctl__nmi_watchdog_enabled()

2020-03-10T17:46:19+00:00

The NMI watchdog status is required for metric group constraint examination. Factor out sysctl__nmi_watchdog_enabled() to retrieve the NMI watchdog status. Users may count more than one metric group each time. If so, the NMI watchdog status may be retrieved several times. To reduce the overhead, cache the NMI watchdog status. Replace the NMI watchdog status checking in print_footer() by sysctl__nmi_watchdog_enabled(). Suggested-by: Andi Kleen Signed-off-by: Kan Liang Acked-by: Jiri Olsa Cc: Andi Kleen Cc: Jin Yao Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Ravi Bangoria Link: http://lore.kernel.org/lkml/1582581564-184429-4-git-send-email-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf record: Put a copy of kcore into the perf.data directory

2019-11-06T18:43:05+00:00

Add a new 'perf record' option '--kcore' which will put a copy of /proc/kcore, kallsyms and modules into a perf.data directory. Note, that without the --kcore option, output goes to a file as previously. The tools' -o and -i options work with either a file name or directory name. Example: $ sudo perf record --kcore uname $ sudo tree perf.data perf.data ├── kcore_dir │ ├── kallsyms │ ├── kcore │ └── modules └── data $ sudo perf script -v build id event received for vmlinux: 1eaa285996affce2d74d8e66dcea09a80c9941de build id event received for [vdso]: 8bbaf5dc62a9b644b4d4e4539737e104e4a84541 Samples for 'cycles' event do not have CPU attribute set. Skipping 'cpu' field. Using CPUID GenuineIntel-6-8E-A Using perf.data/kcore_dir/kcore for kernel data Using perf.data/kcore_dir/kallsyms for symbols perf 19058 506778.423729: 1 cycles: ffffffffa2caa548 native_write_msr+0x8 (vmlinux) perf 19058 506778.423733: 1 cycles: ffffffffa2caa548 native_write_msr+0x8 (vmlinux) perf 19058 506778.423734: 7 cycles: ffffffffa2caa548 native_write_msr+0x8 (vmlinux) perf 19058 506778.423736: 117 cycles: ffffffffa2caa54a native_write_msr+0xa (vmlinux) perf 19058 506778.423738: 2092 cycles: ffffffffa2c9b7b0 native_apic_msr_write+0x0 (vmlinux) perf 19058 506778.423740: 37380 cycles: ffffffffa2f121d0 perf_event_addr_filters_exec+0x0 (vmlinux) uname 19058 506778.423751: 582673 cycles: ffffffffa303a407 propagate_protected_usage+0x147 (vmlinux) uname 19058 506778.423892: 2241841 cycles: ffffffffa2cae0c9 unwind_next_frame.part.5+0x79 (vmlinux) uname 19058 506778.424430: 2457397 cycles: ffffffffa3019232 check_memory_region+0x52 (vmlinux) Committer testing: # rm -rf perf.data* # perf record sleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.024 MB perf.data (7 samples) ] # ls -l perf.data -rw-------. 1 root root 34772 Oct 21 11:08 perf.data # perf record --kcore uname Linux [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.024 MB perf.data (7 samples) ] ls[root@quaco ~]# ls -lad perf.data* drwx------. 3 root root 4096 Oct 21 11:08 perf.data -rw-------. 1 root root 34772 Oct 21 11:08 perf.data.old # perf evlist -v cycles: size: 112, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|PERIOD, read_format: ID, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1, task: 1, precise_ip: 3, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1 # perf evlist -v -i perf.data/data cycles: size: 112, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|PERIOD, read_format: ID, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1, task: 1, precise_ip: 3, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1 # Signed-off-by: Adrian Hunter Reviewed-by: Jiri Olsa Tested-by: Arnaldo Carvalho de Melo Link: http://lore.kernel.org/lkml/20191004083121.12182-6-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf data: Rename directory "header" file to "data"

2019-11-06T18:43:05+00:00

In preparation to support a single file directory format, rename "header" to "data" because "header" is a mis-leading name when there is only 1 file. Note, in the multi-file case, the "header" file also contains data. Signed-off-by: Adrian Hunter Reviewed-by: Jiri Olsa Link: http://lore.kernel.org/lkml/20191004083121.12182-4-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Fix resource leak of closedir() on the error paths

2019-10-15T14:54:11+00:00

Both build_mem_topology() and rm_rf_depth_pat() have resource leaks of closedir() on the error paths. Fix this by calling closedir() before function returns. Fixes: e2091cedd51b ("perf tools: Add MEM_TOPOLOGY feature to perf data file") Fixes: cdb6b0235f17 ("perf tools: Add pattern name checking to rm_rf") Signed-off-by: Yunfeng Ye Acked-by: Jiri Olsa Cc: Alexander Shishkin Cc: Alexei Starovoitov Cc: Alexey Budankov Cc: Andi Kleen Cc: Daniel Borkmann Cc: Feilong Lin Cc: Hu Shiyuan Cc: Igor Lubashev Cc: Kan Liang Cc: Mark Rutland Cc: Martin KaFai Lau Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Song Liu Cc: Yonghong Song Link: http://lore.kernel.org/lkml/cd5f7cd2-b80d-6add-20a1-32f4f43e0744@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

perf copyfile: Move copyfile routines to separate files

2019-09-25T12:51:49+00:00

Further reducing the util.c hodgepodge files. Cc: Adrian Hunter Cc: Jiri Olsa Cc: Namhyung Kim Link: https://lkml.kernel.org/n/tip-0i62zh7ok25znibyebgq0qs4@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

libperf: Move 'page_size' global variable to libperf

2019-09-25T12:51:48+00:00

We need the 'page_size' variable in libperf, so move it there. Add a libperf_init() as a global libperf init function to obtain this value via sysconf() at tool start. Committer notes: Add internal/lib.h to tools/perf/ files using 'page_size', sometimes replacing util.h with it if that was the only reason for having util.h included. Signed-off-by: Jiri Olsa Cc: Alexander Shishkin Cc: Michael Petlan Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lore.kernel.org/lkml/20190913132355.21634-33-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf debug: Remove needless include directives from debug.h

2019-08-31T22:10:19+00:00

All we need there is a forward declaration for 'union perf_event', so remove it from there and add missing header directives in places using things from this indirect include. Cc: Adrian Hunter Cc: Jiri Olsa Cc: Namhyung Kim Link: https://lkml.kernel.org/n/tip-7ftk0ztstqub1tirjj8o8xbl@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Remove perf.h from source files not needing it

2019-08-29T20:38:32+00:00

With the movement of lots of stuff out of perf.h to other headers we ended up not needing it in lots of places, remove it from those places. Cc: Adrian Hunter Cc: Jiri Olsa Cc: Namhyung Kim Link: https://lkml.kernel.org/n/tip-c718m0sxxwp73lp9d8vpihb4@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf cacheline: Move cacheline related routines to separate files

2019-08-26T14:58:29+00:00

To disentangle util/sort.h a bit more. Cc: Adrian Hunter Cc: Jiri Olsa Cc: Namhyung Kim Link: https://lkml.kernel.org/n/tip-6kbf2cauas06rbqp15pyter5@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo