Jin Yao e582b82c16 perf/core: Drop kernel samples even though :u is specified ...

commit cc1582c231ea041fbc68861dfaf957eaf902b829 upstream.

When doing sampling, for example:

  perf record -e cycles:u ...

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.

The patch drops the kernel samples if exclude_kernel is specified.

For example, test on Haswell desktop:

  perf record -e cycles:u <mgen>
  perf report --stdio

Before patch applied:

    99.77%  mgen     mgen              [.] buf_read
     0.20%  mgen     mgen              [.] rand_buf_init
     0.01%  mgen     [kernel.vmlinux]  [k] apic_timer_interrupt
     0.00%  mgen     mgen              [.] last_free_elem
     0.00%  mgen     libc-2.23.so      [.] __random_r
     0.00%  mgen     libc-2.23.so      [.] _int_malloc
     0.00%  mgen     mgen              [.] rand_array_init
     0.00%  mgen     [kernel.vmlinux]  [k] page_fault
     0.00%  mgen     libc-2.23.so      [.] __random
     0.00%  mgen     libc-2.23.so      [.] __strcasestr
     0.00%  mgen     ld-2.23.so        [.] strcmp
     0.00%  mgen     ld-2.23.so        [.] _dl_start
     0.00%  mgen     libc-2.23.so      [.] sched_setaffinity@@GLIBC_2.3.4
     0.00%  mgen     ld-2.23.so        [.] _start

We can see kernel symbols apic_timer_interrupt and page_fault.

After patch applied:

    99.79%  mgen     mgen           [.] buf_read
     0.19%  mgen     mgen           [.] rand_buf_init
     0.00%  mgen     libc-2.23.so   [.] __random_r
     0.00%  mgen     mgen           [.] rand_array_init
     0.00%  mgen     mgen           [.] last_free_elem
     0.00%  mgen     libc-2.23.so   [.] vfprintf
     0.00%  mgen     libc-2.23.so   [.] rand
     0.00%  mgen     libc-2.23.so   [.] __random
     0.00%  mgen     libc-2.23.so   [.] _int_malloc
     0.00%  mgen     libc-2.23.so   [.] _IO_doallocbuf
     0.00%  mgen     ld-2.23.so     [.] do_lookup_x
     0.00%  mgen     ld-2.23.so     [.] open_verify.constprop.7
     0.00%  mgen     ld-2.23.so     [.] _dl_important_hwcaps
     0.00%  mgen     libc-2.23.so   [.] sched_setaffinity@@GLIBC_2.3.4
     0.00%  mgen     ld-2.23.so     [.] _start

There are only userspace symbols.

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Cc: jolsa@kernel.org
Cc: kan.liang@intel.com
Cc: mark.rutland@arm.com
Cc: will.deacon@arm.com
Cc: yao.jin@intel.com
Link: http://lkml.kernel.org/r/1495706947-3744-1-git-send-email-yao.jin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2017-06-14 13:16:25 +02:00

..

bpf

bpf, inode: disallow userns mounts

2016-06-24 10:18:17 -07:00

configs

kconfig: tinyconfig: provide whole choice blocks to avoid warnings

2016-09-24 10:07:42 +02:00

debug

kernel/debug/debug_core.c: more properly delay for secondary CPUs

2017-01-06 11:16:16 +01:00

events

perf/core: Drop kernel samples even though :u is specified

2017-06-14 13:16:25 +02:00

gcov

gcov: add support for GCC 5.1

2015-06-30 19:44:57 -07:00

irq

genirq: Fix chained interrupt data ordering

2017-05-25 14:30:17 +02:00

livepatch

livepatch: x86: fix relocation computation with kASLR

2015-11-11 17:36:04 +01:00

locking

locking/rtmutex: Use READ_ONCE() in rt_mutex_owner()

2016-12-15 08:49:22 -08:00

power

PM / sleep: fix device reference leak in test_suspend

2016-11-26 09:54:53 +01:00

printk

printk: use rcuidle console tracepoint

2017-02-23 17:43:10 +01:00

rcu

rcu: Fix soft lockup for rcu_nocb_kthread

2016-12-08 07:15:24 +01:00

sched

sched/fair: Initialize throttle_count for new task-groups lazily

2017-05-25 14:30:12 +02:00

time

tick/broadcast: Prevent NULL pointer dereference

2017-01-12 11:22:51 +01:00

trace

tracing/kprobes: Enforce kprobes teardown after testing

2017-05-25 14:30:17 +02:00

.gitignore

certs: add .gitignore to stop git nagging about x509_certificate_list

2015-10-21 15:18:35 +01:00

acct.c

acct: check FMODE_CAN_WRITE

2015-04-11 22:27:55 -04:00

async.c

…

audit_fsnotify.c

audit: clean simple fsnotify implementation

2015-08-06 16:14:53 -04:00

audit_tree.c

audit: audit_tree_match can be boolean

2015-11-04 08:23:51 -05:00

audit_watch.c

audit: fix exe_file access in audit_exe_compare

2016-09-24 10:07:36 +02:00

audit.c

mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd

2015-11-06 17:50:42 -08:00

audit.h

audit: audit_tree_match can be boolean

2015-11-04 08:23:51 -05:00

auditfilter.c

audit: fix comment block whitespace

2015-11-04 08:23:51 -05:00

auditsc.c

audit: fix a double fetch in audit_log_single_execve_arg()

2016-08-20 18:09:22 +02:00

backtracetest.c

…

bounds.c

…

capability.c

exec: Ensure mm->user_ns contains the execed files

2017-01-06 11:16:14 +01:00

cgroup_freezer.c

cgroup: fix handling of multi-destination migration from subtree_control enabling

2015-12-03 10:18:21 -05:00

cgroup_pids.c

cgroup_pids: don't account for the root cgroup

2015-12-03 10:18:21 -05:00

cgroup.c

cgroup, kthread: close race window where new kthreads can be migrated to non-root cgroups

2017-04-21 09:30:04 +02:00

compat.c

compat: cleanup coding in compat_get_bitmap() and compat_put_bitmap()

2015-06-04 23:57:18 +02:00

configs.c

…

context_tracking.c

context_tracking: avoid irq_save/irq_restore on guest entry and exit

2015-11-10 12:06:23 +01:00

cpu_pm.c

kernel/cpu_pm: fix cpu_cluster_pm_exit comment

2015-09-03 02:42:20 +02:00

cpu.c

stable-fixup: hotplug: fix unused function warning

2017-01-12 11:22:48 +01:00

cpuset.c

cpuset: consider dying css as offline

2017-06-14 13:16:23 +02:00

crash_dump.c

…

cred.c

cred: Reject inodes with invalid ids in set_create_file_as()

2016-09-15 08:27:49 +02:00

delayacct.c

…

dma.c

…

elfcore.c

…

exec_domain.c

Remove rest of exec domains.

2015-04-12 21:03:31 +02:00

exit.c

wait/ptrace: assume __WALL if the child is traced

2016-06-07 18:14:35 -07:00

extable.c

kernel/extable.c: remove duplicated include

2015-09-10 13:29:01 -07:00

fork.c

stackprotector: Increase the per-task stack canary's random range from 32 bits to 64 bits on 64-bit platforms

2017-06-14 13:16:23 +02:00

freezer.c

…

futex_compat.c

ptrace: use fsuid, fsgid, effective creds for fs access checks

2016-02-25 12:01:16 -08:00

futex.c

futex: Add missing error handling to FUTEX_REQUEUE_PI

2017-03-22 12:04:19 +01:00

groups.c

kernel: conditionally support non-root users, groups and capabilities

2015-04-15 16:35:22 -07:00

hung_task.c

kernel/hung_task.c: change hung_task.c to use for_each_process_thread()

2015-04-15 16:35:22 -07:00

irq_work.c

treewide: Remove old email address

2015-11-23 09:44:58 +01:00

jump_label.c

jump_labels: API for flushing deferred jump label updates

2017-01-19 20:17:19 +01:00

kallsyms.c

…

kcmp.c

ptrace: use fsuid, fsgid, effective creds for fs access checks

2016-02-25 12:01:16 -08:00

Kconfig.freezer

…

Kconfig.hz

…

Kconfig.locks

locking/qrwlock: Rename QUEUE_RWLOCK to QUEUED_RWLOCKS

2015-05-12 09:46:00 +02:00

Kconfig.preempt

…

kexec_core.c

kexec: use file name as the output message prefix

2015-11-06 17:50:42 -08:00

kexec_file.c

kexec: fix double-free when failing to relocate the purgatory

2016-09-24 10:07:36 +02:00

kexec_internal.h

kexec: split kexec_file syscall code to kexec_file.c

2015-09-10 13:29:01 -07:00

kexec.c

kexec: use file name as the output message prefix

2015-11-06 17:50:42 -08:00

kmod.c

kmod: don't run async usermode helper as a child of kworker thread

2015-10-23 17:55:10 +09:00

kprobes.c

tracing/kprobes: Enforce kprobes teardown after testing

2017-05-25 14:30:17 +02:00

ksysfs.c

kexec: split kexec_load syscall from kexec core code

2015-09-10 13:29:01 -07:00

kthread.c

cgroup, kthread: close race window where new kthreads can be migrated to non-root cgroups

2017-04-21 09:30:04 +02:00

latencytop.c

…

Makefile

sys_membarrier(): system-wide memory barrier (generic, x86)

2015-09-11 15:21:34 -07:00

membarrier.c

Fix: Disable sys_membarrier when nohz_full is enabled

2017-03-12 06:37:26 +01:00

memremap.c

mm: fix devm_memremap_pages crash, use mem_hotplug_{begin, done}

2017-01-19 20:17:18 +01:00

module_signing.c

KEYS: Merge the type-specific data with the payload data

2015-10-21 15:18:36 +01:00

module-internal.h

…

module.c

module: Invalidate signatures on force-loaded modules

2016-08-20 18:09:27 +02:00

notifier.c

Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2015-09-01 08:40:25 -07:00

nsproxy.c

…

padata.c

padata: free correct variable

2017-05-20 14:27:02 +02:00

panic.c

printk: do cond_resched() between lines while outputting to consoles

2016-02-17 12:30:57 -08:00

params.c

Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

2015-11-09 15:53:39 -08:00

pid_namespace.c

pid_ns: Sleep in TASK_INTERRUPTIBLE in zap_pid_ns_processes

2017-05-25 14:30:11 +02:00

pid.c

pidns: fix NULL dereference in __task_pid_nr_ns()

2015-11-24 12:03:55 -08:00

profile.c

mm: rename alloc_pages_exact_node() to __alloc_pages_node()

2015-09-08 15:35:28 -07:00

ptrace.c

ptrace: Properly initialize ptracer_cred on fork

2017-06-14 13:16:20 +02:00

range.c

…

reboot.c

kexec: split kexec_load syscall from kexec core code

2015-09-10 13:29:01 -07:00

relay.c

kernel/relay.c: use kvfree() in relay_free_page_array()

2015-06-30 19:44:59 -07:00

resource.c

kernel/resource.c: fix muxed resource handling in __request_region()

2016-03-03 15:07:29 -08:00

seccomp.c

seccomp: always propagate NO_NEW_PRIVS on tsync

2016-03-03 15:07:25 -08:00

signal.c

kernel/signal.c: unexport sigsuspend()

2015-11-20 16:17:32 -08:00

smp.c

mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd

2015-11-06 17:50:42 -08:00

smpboot.c

stop_machine: Kill smp_hotplug_thread->pre_unpark, introduce stop_machine_unpark()

2015-10-20 10:23:55 +02:00

smpboot.h

…

softirq.c

…

stacktrace.c

…

stop_machine.c

kernel: remove stop_machine() Kconfig dependency

2015-12-12 10:15:34 -08:00

sys_ni.c

mm: mlock: add new mlock system call

2015-11-05 19:34:48 -08:00

sys.c

prctl: take mmap sem for writing to protect against others

2016-02-25 12:01:25 -08:00

sysctl_binary.c

fs/coredump: prevent fsuid=0 dumps into user-controlled directories

2016-04-12 09:08:58 -07:00

sysctl.c

mnt: Add a per mount namespace limit on the number of mounts

2017-04-30 05:49:28 +02:00

task_work.c

task_work: remove fifo ordering guarantee

2015-09-05 13:46:58 -07:00

taskstats.c

…

test_kprobes.c

…

torture.c

torture: Consolidate cond_resched_rcu_qs() into stutter_wait()

2015-10-06 11:25:01 -07:00

tracepoint.c

tracepoint: Give priority to probes of tracepoints

2015-10-25 21:33:54 -04:00

tsacct.c

…

uid16.c

…

up.c

…

user_namespace.c

capabilities: ambient capabilities

2015-09-04 16:54:41 -07:00

user-return-notifier.c

…

user.c

…

utsname_sysctl.c

…

utsname.c

…

watchdog.c

kernel/watchdog: use nmi registers snapshot in hardlockup handler

2017-01-06 11:16:16 +01:00

workqueue_internal.h

…

workqueue.c

workqueue: fix rebind bound workers warning

2016-05-18 17:06:50 -07:00