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  1. 12 Jul, 2013 4 commits
    • Peter Zijlstra's avatar
      perf: Fix perf_lock_task_context() vs RCU · 058ebd0e
      Peter Zijlstra authored 
      Jiri managed to trigger this warning:

 [] ======================================================
 [] [ INFO: possible circular locking dependency detected ]
 [] 3.10.0+ #228 Tainted: G        W
 [] -------------------------------------------------------
 [] p/6613 is trying to acquire lock:
 []  (rcu_node_0){..-...}, at: [<ffffffff810ca797>] rcu_read_unlock_special+0xa7/0x250
 []
 [] but task is already holding lock:
 []  (&ctx->lock){-.-...}, at: [<ffffffff810f2879>] perf_lock_task_context+0xd9/0x2c0
 []
 [] which lock already depends on the new lock.
 []
 [] the existing dependency chain (in reverse order) is:
 []
 [] -> #4 (&ctx->lock){-.-...}:
 [] -> #3 (&rq->lock){-.-.-.}:
 [] -> #2 (&p->pi_lock){-.-.-.}:
 [] -> #1 (&rnp->nocb_gp_wq[1]){......}:
 [] -> #0 (rcu_node_0){..-...}:

Paul was quick to explain that due to preemptible RCU we cannot call
rcu_read_unlock() while holding scheduler (or nested) locks when part
of the read side critical section was preemptible.

Therefore solve it by making the entire RCU read side non-preemptible.

Also pull out the retry from under the non-preempt to play nice with RT.
Reported-by: default avatarJiri Olsa <jolsa@redhat.com>
Helped-out-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      058ebd0e
    • Jiri Olsa's avatar
      perf: Remove WARN_ON_ONCE() check in __perf_event_enable() for valid scenario · 06f41796
      Jiri Olsa authored 
      The '!ctx->is_active' check has a valid scenario, so
there's no need for the warning.

The reason is that there's a time window between the
'ctx->is_active' check in the perf_event_enable() function
and the __perf_event_enable() function having:

  - IRQs on
  - ctx->lock unlocked

where the task could be killed and 'ctx' deactivated by
perf_event_exit_task(), ending up with the warning below.

So remove the WARN_ON_ONCE() check and add comments to
explain it all.

This addresses the following warning reported by Vince Weaver:

[  324.983534] ------------[ cut here ]------------
[  324.984420] WARNING: at kernel/events/core.c:1953 __perf_event_enable+0x187/0x190()
[  324.984420] Modules linked in:
[  324.984420] CPU: 19 PID: 2715 Comm: nmi_bug_snb Not tainted 3.10.0+ #246
[  324.984420] Hardware name: Supermicro X8DTN/X8DTN, BIOS 4.6.3 01/08/2010
[  324.984420]  0000000000000009 ffff88043fce3ec8 ffffffff8160ea0b ffff88043fce3f00
[  324.984420]  ffffffff81080ff0 ffff8802314fdc00 ffff880231a8f800 ffff88043fcf7860
[  324.984420]  0000000000000286 ffff880231a8f800 ffff88043fce3f10 ffffffff8108103a
[  324.984420] Call Trace:
[  324.984420]  <IRQ>  [<ffffffff8160ea0b>] dump_stack+0x19/0x1b
[  324.984420]  [<ffffffff81080ff0>] warn_slowpath_common+0x70/0xa0
[  324.984420]  [<ffffffff8108103a>] warn_slowpath_null+0x1a/0x20
[  324.984420]  [<ffffffff81134437>] __perf_event_enable+0x187/0x190
[  324.984420]  [<ffffffff81130030>] remote_function+0x40/0x50
[  324.984420]  [<ffffffff810e51de>] generic_smp_call_function_single_interrupt+0xbe/0x130
[  324.984420]  [<ffffffff81066a47>] smp_call_function_single_interrupt+0x27/0x40
[  324.984420]  [<ffffffff8161fd2f>] call_function_single_interrupt+0x6f/0x80
[  324.984420]  <EOI>  [<ffffffff816161a1>] ? _raw_spin_unlock_irqrestore+0x41/0x70
[  324.984420]  [<ffffffff8113799d>] perf_event_exit_task+0x14d/0x210
[  324.984420]  [<ffffffff810acd04>] ? switch_task_namespaces+0x24/0x60
[  324.984420]  [<ffffffff81086946>] do_exit+0x2b6/0xa40
[  324.984420]  [<ffffffff8161615c>] ? _raw_spin_unlock_irq+0x2c/0x30
[  324.984420]  [<ffffffff81087279>] do_group_exit+0x49/0xc0
[  324.984420]  [<ffffffff81096854>] get_signal_to_deliver+0x254/0x620
[  324.984420]  [<ffffffff81043057>] do_signal+0x57/0x5a0
[  324.984420]  [<ffffffff8161a164>] ? __do_page_fault+0x2a4/0x4e0
[  324.984420]  [<ffffffff8161665c>] ? retint_restore_args+0xe/0xe
[  324.984420]  [<ffffffff816166cd>] ? retint_signal+0x11/0x84
[  324.984420]  [<ffffffff81043605>] do_notify_resume+0x65/0x80
[  324.984420]  [<ffffffff81616702>] retint_signal+0x46/0x84
[  324.984420] ---[ end trace 442ec2f04db3771a ]---
Reported-by: default avatarVince Weaver <vincent.weaver@maine.edu>
Signed-off-by: default avatarJiri Olsa <jolsa@redhat.com>
Suggested-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1373384651-6109-2-git-send-email-jolsa@redhat.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      06f41796
    • Jiri Olsa's avatar
      perf: Clone child context from parent context pmu · 734df5ab
      Jiri Olsa authored 
      Currently when the child context for inherited events is
created, it's based on the pmu object of the first event
of the parent context.

This is wrong for the following scenario:

  - HW context having HW and SW event
  - HW event got removed (closed)
  - SW event stays in HW context as the only event
    and its pmu is used to clone the child context

The issue starts when the cpu context object is touched
based on the pmu context object (__get_cpu_context). In
this case the HW context will work with SW cpu context
ending up with following WARN below.

Fixing this by using parent context pmu object to clone
from child context.

Addresses the following warning reported by Vince Weaver:

[ 2716.472065] ------------[ cut here ]------------
[ 2716.476035] WARNING: at kernel/events/core.c:2122 task_ctx_sched_out+0x3c/0x)
[ 2716.476035] Modules linked in: nfsd auth_rpcgss oid_registry nfs_acl nfs locn
[ 2716.476035] CPU: 0 PID: 3164 Comm: perf_fuzzer Not tainted 3.10.0-rc4 #2
[ 2716.476035] Hardware name: AOpen   DE7000/nMCP7ALPx-DE R1.06 Oct.19.2012, BI2
[ 2716.476035]  0000000000000000 ffffffff8102e215 0000000000000000 ffff88011fc18
[ 2716.476035]  ffff8801175557f0 0000000000000000 ffff880119fda88c ffffffff810ad
[ 2716.476035]  ffff880119fda880 ffffffff810af02a 0000000000000009 ffff880117550
[ 2716.476035] Call Trace:
[ 2716.476035]  [<ffffffff8102e215>] ? warn_slowpath_common+0x5b/0x70
[ 2716.476035]  [<ffffffff810ab2bd>] ? task_ctx_sched_out+0x3c/0x5f
[ 2716.476035]  [<ffffffff810af02a>] ? perf_event_exit_task+0xbf/0x194
[ 2716.476035]  [<ffffffff81032a37>] ? do_exit+0x3e7/0x90c
[ 2716.476035]  [<ffffffff810cd5ab>] ? __do_fault+0x359/0x394
[ 2716.476035]  [<ffffffff81032fe6>] ? do_group_exit+0x66/0x98
[ 2716.476035]  [<ffffffff8103dbcd>] ? get_signal_to_deliver+0x479/0x4ad
[ 2716.476035]  [<ffffffff810ac05c>] ? __perf_event_task_sched_out+0x230/0x2d1
[ 2716.476035]  [<ffffffff8100205d>] ? do_signal+0x3c/0x432
[ 2716.476035]  [<ffffffff810abbf9>] ? ctx_sched_in+0x43/0x141
[ 2716.476035]  [<ffffffff810ac2ca>] ? perf_event_context_sched_in+0x7a/0x90
[ 2716.476035]  [<ffffffff810ac311>] ? __perf_event_task_sched_in+0x31/0x118
[ 2716.476035]  [<ffffffff81050dd9>] ? mmdrop+0xd/0x1c
[ 2716.476035]  [<ffffffff81051a39>] ? finish_task_switch+0x7d/0xa6
[ 2716.476035]  [<ffffffff81002473>] ? do_notify_resume+0x20/0x5d
[ 2716.476035]  [<ffffffff813654f5>] ? retint_signal+0x3d/0x78
[ 2716.476035] ---[ end trace 827178d8a5966c3d ]---
Reported-by: default avatarVince Weaver <vincent.weaver@maine.edu>
Signed-off-by: default avatarJiri Olsa <jolsa@redhat.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1373384651-6109-1-git-send-email-jolsa@redhat.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      734df5ab
    • Ingo Molnar's avatar
      Merge tag 'perf-urgent-for-mingo' of... · c3a1b0cb
      Ingo Molnar authored 
      Merge tag 'perf-urgent-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent

Pull perf/urgent fixes from Arnaldo Carvalho de Melo:

 * Fix some freeing bugs on the parsing error paths, from Adrian Hunter.

 * Update symbol_conf.nr_events when processing attribute events, fix from Adrian Hunter.

 * Fix missing increment in sample parsing when PERF_SAMPLE_STACK_USER
   is present, from Adrian Hunt.

 * Fix count parameter to read call in event_format__new, from David Ahern.

 * Remove -A/--append option, not working for a long time, from Jiri Olsa.

 * Remove -f/--force option, was a no-op for quite some time, from Jiri Olsa.

 * Fix -x/--exclude-other option for report command, from Jiri Olsa.

 * Cross build fixes, at least one for Android, from Joonsoo Kim.

 * Fix memory allocation fail check in mem{set,cpy} 'perf bench' workloads,
   from Kirill A. Shutemov.

 * Revert regression in configuration of Python support, from Michael Witten.

 * Fix -ldw/-lelf link test when static linking, from Mike Frysinger.

 * Fix issues with multiple children processing in perf_evlist__start_workload(),
   from Namhyung Kim.

 * Fix broken include in Context.xs ('perf script'), from Ramkumar Ramachandra.

 * Fixes for build problems, from Robert Richter.

 * Fix a typo of a Power7 event name, from Runzhen Wang.

 * Avoid sending SIGTERM to random processes in 'perf stat', fix from Stephane Eranian.

 * Fix per-socket output bug for uncore events in 'perf stat', from Stephane Eranian.

 * Fix vdso list searching, from Waiman Long.
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      c3a1b0cb
  3. 10 Jul, 2013 2 commits
    • Ramkumar Ramachandra's avatar
      perf script: Fix broken include in Context.xs · 750ade7e
      Ramkumar Ramachandra authored 
      765532c8 (perf script: Finish the rename from trace to script,
2010-12-23) made a mistake during find-and-replace replacing
"../../../util/trace-event.h" with "../../../util/script-event.h", a
non-existent file.  Fix this include.
Signed-off-by: default avatarRamkumar Ramachandra <artagnon@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1373364033-7918-3-git-send-email-artagnon@gmail.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      750ade7e
    • Mike Frysinger's avatar
      perf tools: Fix -ldw/-lelf link test when static linking · d14c4965
      Mike Frysinger authored 
      Since libelf sometimes uses libpthread, we have to list that after -lelf
when someone tries to build statically.  Else things go boom:

Makefile:479: *** No libelf.h/libelf found, please install \
	libelf-dev/elfutils-libelf-devel.  Stop.

Similarly, the -ldw test fails as it often uses -lz:

Makefile:462: No libdw.h found or old libdw.h found or elfutils is older \
	than 0.138, disables dwarf support. Please install new elfutils-devel/libdw-dev

And if we add debugging to try-cc, we see:
+ echo '#include <dwarf.h>

int main(void)
{
        Dwarf *dbg = dwarf_begin(0, DWARF_C_READ);
        return (long)dbg;
}'
+ i686-pc-linux-gnu-gcc -x c - -O2 -pipe -march=atom -mtune=atom -mfpmath=sse -g \
	-D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE \
	-ldw -lelf -static -lpthread -lrt -lelf -lm -o .24368
/usr/lib/libdw.a(dwarf_begin_elf.o):function check_section.isra.1: error: undefined reference to 'inflateInit_'
/usr/lib/libdw.a(dwarf_begin_elf.o):function check_section.isra.1: error: undefined reference to 'inflate'
/usr/lib/libdw.a(dwarf_begin_elf.o):function check_section.isra.1: error: undefined reference to 'inflateReset'
/usr/lib/libdw.a(dwarf_begin_elf.o):function check_section.isra.1: error: undefined reference to 'inflateEnd'

+ echo '#include <libelf.h>

int main(void)
{
        Elf *elf = elf_begin(0, ELF_C_READ, 0);
        return (long)elf;
}'
+ i686-pc-linux-gnu-gcc -x c - -O2 -pipe -march=atom -mtune=atom -mfpmath=sse -g \
	-D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE \
	-static -lpthread -lrt -lelf -lm -o .19216
/usr/lib/libelf.a(elf_begin.o):function file_read_elf: error: undefined reference to 'pthread_rwlock_init'
/usr/lib/libelf.a(elf_begin.o):function __libelf_read_mmaped_file: error: undefined reference to 'pthread_rwlock_init'
/usr/lib/libelf.a(elf_begin.o):function __libelf_read_mmaped_file: error: undefined reference to 'pthread_rwlock_init'
/usr/lib/libelf.a(elf_begin.o):function read_file: error: undefined reference to 'pthread_rwlock_init'
/usr/lib/libelf.a(elf_begin.o):function lock_dup_elf.8072: error: undefined reference to 'pthread_rwlock_unlock'
/usr/lib/libelf.a(elf_begin.o):function lock_dup_elf.8072: error: undefined reference to 'pthread_rwlock_wrlock'
/usr/lib/libelf.a(elf_begin.o):function elf_begin: error: undefined reference to 'pthread_rwlock_rdlock'
/usr/lib/libelf.a(elf_begin.o):function elf_begin: error: undefined reference to 'pthread_rwlock_unlock'
Signed-off-by: default avatarMike Frysinger <vapier@gentoo.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1368073064-18276-1-git-send-email-vapier@gentoo.orgSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      d14c4965
  5. 09 Jul, 2013 1 commit
    • Michael Witten's avatar
      perf tools: Revert regression in configuration of Python support · a363a9da
      Michael Witten authored 
      Among other things, the following:

  commit 31160d7f
  Date:   Tue Jan 8 16:22:36 2013 -0500
  perf tools: Fix GNU make v3.80 compatibility issue

attempts to aid the user by tapping into an existing error message,
as described in the commit message:

  ... Also fix an issue where _get_attempt was called with only
  one argument. This prevented the error message from printing
  the name of the variable that can be used to fix the problem.

or more precisely:

  -$(if $($(1)),$(call _ge_attempt,$($(1)),$(1)),$(call _ge_attempt,$(2)))
  +$(if $($(1)),$(call _ge_attempt,$($(1)),$(1)),$(call _ge_attempt,$(2),$(1)))

However, The "missing" argument was in fact missing on purpose; it's
absence is a signal that the error message should be skipped, because
the failure would be due to the default value, not any user-supplied
value.  This can be seen in how `_ge_attempt' uses `gea_err' (in the
config/utilities.mak file):

  _ge_attempt = $(if $(get-executable),$(get-executable),$(_gea_warn)$(call _gea_err,$(2)))
  _gea_warn = $(warning The path '$(1)' is not executable.)
  _gea_err  = $(if $(1),$(error Please set '$(1)' appropriately))

That is, because the argument is no longer missing, the value `$(1)'
(associated with `_gea_err') always evaluates to true, thus always
triggering the error condition that is meant to be reserved for
only the case when a user explicitly supplies an invalid value.

Concretely, the result is a regression in the Makefile's configuration
of python support; rather than gracefully disable support when the
relevant executables cannot be found according to default values, the
build process halts in error as though the user explicitly supplied
the values.

This new commit simply reverts the offending one-line change.
Reported-by: default avatarPekka Enberg <penberg@kernel.org>
Link: http://lkml.kernel.org/r/CAOJsxLHv17Ys3M7P5q25imkUxQW6LE_vABxh1N3Tt7Mv6Ho4iw@mail.gmail.comSigned-off-by: default avatarMichael Witten <mfwitten@gmail.com>
      a363a9da
  7. 08 Jul, 2013 20 commits
  9. 05 Jul, 2013 2 commits
  11. 02 Jul, 2013 11 commits
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