linux/kernel/events/core.c, branch v3.18

perf: Fix corruption of sibling list with hotplug

2014-11-16T08:45:46Z

When a CPU hotplugged out, we call perf_remove_from_context() (via perf_event_exit_cpu()) to rip each CPU-bound event out of its PMU's cpu context, but leave siblings grouped together. Freeing of these events is left to the mercy of the usual refcounting. When a CPU-bound event's refcount drops to zero we cross-call to __perf_remove_from_context() to clean it up, detaching grouped siblings. This works when the relevant CPU is online, but will fail if the CPU is currently offline, and we won't detach the event from its siblings before freeing the event, leaving the sibling list corrupt. If the sibling list is later walked (e.g. because the CPU cam online again before a remaining sibling's refcount drops to zero), we will walk the now corrupted siblings list, potentially dereferencing garbage values. Given that the events should never be scheduled again (as we removed them from their context), we can simply detatch siblings when the CPU goes down in the first place. If the CPU comes back online, the redundant call to __perf_remove_from_context() is safe. Reported-by: Drew Richardson Signed-off-by: Mark Rutland Signed-off-by: Peter Zijlstra (Intel) Cc: vincent.weaver@maine.edu Cc: Vince Weaver Cc: Will Deacon Cc: Arnaldo Carvalho de Melo Cc: Linus Torvalds Link: http://lkml.kernel.org/r/1415203904-25308-2-git-send-email-mark.rutland@arm.com Signed-off-by: Ingo Molnar

perf: Fix and clean up initialization of pmu::event_idx

2014-10-28T09:51:01Z

Andy reported that the current state of event_idx is rather confused. So remove all but the x86_pmu implementation and change the default to return 0 (the safe option). Reported-by: Andy Lutomirski Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho de Melo Cc: Benjamin Herrenschmidt Cc: Christoph Lameter Cc: Cody P Schafer Cc: Cody P Schafer Cc: Heiko Carstens Cc: Hendrik Brueckner Cc: Himangi Saraogi Cc: Linus Torvalds Cc: Martin Schwidefsky Cc: Michael Ellerman Cc: Paul Gortmaker Cc: Paul Mackerras Cc: sukadev@linux.vnet.ibm.com Cc: Thomas Huth Cc: Vince Weaver Cc: linux390@de.ibm.com Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-s390@vger.kernel.org Signed-off-by: Ingo Molnar

Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu

2014-10-15T05:48:18Z

Pull percpu consistent-ops changes from Tejun Heo: "Way back, before the current percpu allocator was implemented, static and dynamic percpu memory areas were allocated and handled separately and had their own accessors. The distinction has been gone for many years now; however, the now duplicate two sets of accessors remained with the pointer based ones - this_cpu_*() - evolving various other operations over time. During the process, we also accumulated other inconsistent operations. This pull request contains Christoph's patches to clean up the duplicate accessor situation. __get_cpu_var() uses are replaced with with this_cpu_ptr() and __this_cpu_ptr() with raw_cpu_ptr(). Unfortunately, the former sometimes is tricky thanks to C being a bit messy with the distinction between lvalues and pointers, which led to a rather ugly solution for cpumask_var_t involving the introduction of this_cpu_cpumask_var_ptr(). This converts most of the uses but not all. Christoph will follow up with the remaining conversions in this merge window and hopefully remove the obsolete accessors" * 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (38 commits) irqchip: Properly fetch the per cpu offset percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t -fix ia64: sn_nodepda cannot be assigned to after this_cpu conversion. Use __this_cpu_write. percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t Revert "powerpc: Replace __get_cpu_var uses" percpu: Remove __this_cpu_ptr clocksource: Replace __this_cpu_ptr with raw_cpu_ptr sparc: Replace __get_cpu_var uses avr32: Replace __get_cpu_var with __this_cpu_write blackfin: Replace __get_cpu_var uses tile: Use this_cpu_ptr() for hardware counters tile: Replace __get_cpu_var uses powerpc: Replace __get_cpu_var uses alpha: Replace __get_cpu_var ia64: Replace __get_cpu_var uses s390: cio driver &__get_cpu_var replacements s390: Replace __get_cpu_var uses mips: Replace __get_cpu_var uses MIPS: Replace __get_cpu_var uses in FPU emulator. arm: Replace __this_cpu_ptr with raw_cpu_ptr ...

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

2014-10-13T14:06:09Z

Pull perf fixes from Ingo Molnar: "Two leftover fixes from the v3.17 cycle - these will be forwarded to stable as well, if they prove problem-free in wider testing as well" [ Side note: the "fix perf bug in fork()" fix had also come in through Andrew's patch-bomb - Linus ] * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf: Fix perf bug in fork() perf: Fix unclone_ctx() vs. locking

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

2014-10-13T13:58:15Z

Pull perf updates from Ingo Molnar: "Kernel side updates: - Fix and enhance poll support (Jiri Olsa) - Re-enable inheritance optimization (Jiri Olsa) - Enhance Intel memory events support (Stephane Eranian) - Refactor the Intel uncore driver to be more maintainable (Zheng Yan) - Enhance and fix Intel CPU and uncore PMU drivers (Peter Zijlstra, Andi Kleen) - [ plus various smaller fixes/cleanups ] User visible tooling updates: - Add +field argument support for --field option, so that one can add fields to the default list of fields to show, ie now one can just do: perf report --fields +pid And the pid will appear in addition to the default fields (Jiri Olsa) - Add +field argument support for --sort option (Jiri Olsa) - Honour -w in the report tools (report, top), allowing to specify the widths for the histogram entries columns (Namhyung Kim) - Properly show submicrosecond times in 'perf kvm stat' (Christian Borntraeger) - Add beautifier for mremap flags param in 'trace' (Alex Snast) - perf script: Allow callchains if any event samples them - Don't truncate Intel style addresses in 'annotate' (Alex Converse) - Allow profiling when kptr_restrict == 1 for non root users, kernel samples will just remain unresolved (Andi Kleen) - Allow configuring default options for callchains in config file (Namhyung Kim) - Support operations for shared futexes. (Davidlohr Bueso) - "perf kvm stat report" improvements by Alexander Yarygin: - Save pid string in opts.target.pid - Enable the target.system_wide flag - Unify the title bar output - [ plus lots of other fixes and small improvements. ] Tooling infrastructure changes: - Refactor unit and scale function parameters for PMU parsing routines (Matt Fleming) - Improve DSO long names lookup with rbtree, resulting in great speedup for workloads with lots of DSOs (Waiman Long) - We were not handling POLLHUP notifications for event file descriptors Fix it by filtering entries in the events file descriptor array after poll() returns, refcounting mmaps so that when the last fd pointing to a perf mmap goes away we do the unmap (Arnaldo Carvalho de Melo) - Intel PT prep work, from Adrian Hunter, including: - Let a user specify a PMU event without any config terms - Add perf-with-kcore script - Let default config be defined for a PMU - Add perf_pmu__scan_file() - Add a 'perf test' for tracking with sched_switch - Add 'flush' callback to scripting API - Use ring buffer consume method to look like other tools (Arnaldo Carvalho de Melo) - hists browser (used in top and report) refactorings, getting rid of unused variables and reducing source code size by handling similar cases in a fewer functions (Namhyung Kim). - Replace thread unsafe strerror() with strerror_r() accross the whole tools/perf/ tree (Masami Hiramatsu) - Rename ordered_samples to ordered_events and allow setting a queue size for ordering events (Jiri Olsa) - [ plus lots of fixes, cleanups and other improvements ]" * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (198 commits) perf/x86: Tone down kernel messages when the PMU check fails in a virtual environment perf/x86/intel/uncore: Fix minor race in box set up perf record: Fix error message for --filter option not coming after tracepoint perf tools: Fix build breakage on arm64 targets perf symbols: Improve DSO long names lookup speed with rbtree perf symbols: Encapsulate dsos list head into struct dsos perf bench futex: Sanitize -q option in requeue perf bench futex: Support operations for shared futexes perf trace: Fix mmap return address truncation to 32-bit perf tools: Refactor unit and scale function parameters perf tools: Fix line number in the config file error message perf tools: Convert {record,top}.call-graph option to call-graph.record-mode perf tools: Introduce perf_callchain_config() perf callchain: Move some parser functions to callchain.c perf tools: Move callchain config from record_opts to callchain_param perf hists browser: Fix callchain print bug on TUI perf tools: Use ACCESS_ONCE() instead of volatile cast perf tools: Modify error code for when perf_session__new() fails perf tools: Fix perf record as non root with kptr_restrict == 1 perf stat: Fix --per-core on multi socket systems ...

Merge branch 'for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

2014-10-10T11:24:40Z

Pull cgroup updates from Tejun Heo: "Nothing too interesting. Just a handful of cleanup patches" * 'for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: Revert "cgroup: remove redundant variable in cgroup_mount()" cgroup: remove redundant variable in cgroup_mount() cgroup: fix missing unlock in cgroup_release_agent() cgroup: remove CGRP_RELEASABLE flag perf/cgroup: Remove perf_put_cgroup() cgroup: remove redundant check in cgroup_ino() cpuset: simplify proc_cpuset_show() cgroup: simplify proc_cgroup_show() cgroup: use a per-cgroup work for release agent cgroup: remove bogus comments cgroup: remove redundant code in cgroup_rmdir() cgroup: remove some useless forward declarations cgroup: fix a typo in comment.

perf: Fix perf bug in fork()

2014-10-03T03:41:08Z

Oleg noticed that a cleanup by Sylvain actually uncovered a bug; by calling perf_event_free_task() when failing sched_fork() we will not yet have done the memset() on ->perf_event_ctxp[] and will therefore try and 'free' the inherited contexts, which are still in use by the parent process. This is bad and might explain some outstanding fuzzer failures ... Suggested-by: Oleg Nesterov Reported-by: Oleg Nesterov Reported-by: Sylvain 'ythier' Hitier Signed-off-by: Peter Zijlstra (Intel) Cc: Aaron Tomlin Cc: Andrew Morton Cc: Arnaldo Carvalho de Melo Cc: Daeseok Youn Cc: David Rientjes Cc: Kees Cook Cc: Linus Torvalds Cc: Paul Mackerras Cc: Rik van Riel Cc: Vladimir Davydov Cc: Link: http://lkml.kernel.org/r/20140929101201.GE5430@worktop Signed-off-by: Ingo Molnar

perf: Fix unclone_ctx() vs. locking

2014-10-03T03:41:06Z

The idiot who did 4a1c0f262f88 ("perf: Fix lockdep warning on process exit") forgot to pay attention and fix all similar cases. Do so now. In particular, unclone_ctx() must be called while holding ctx->lock, therefore all such sites are broken for the same reason. Pull the put_ctx() call out from under ctx->lock. Reported-by: Sasha Levin Probably-also-reported-by: Vince Weaver Fixes: 4a1c0f262f88 ("perf: Fix lockdep warning on process exit") Signed-off-by: Peter Zijlstra (Intel) Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Cc: Sasha Levin Cc: Cong Wang Cc: Linus Torvalds Link: http://lkml.kernel.org/r/20140930172308.GI4241@worktop.programming.kicks-ass.net Signed-off-by: Ingo Molnar

perf: fix perf bug in fork()

2014-10-02T23:28:44Z

Revert "perf: Do not allow optimized switch for non-cloned events"

2014-09-24T12:48:13Z

This reverts commit 1f9a7268c67f0290837aada443d28fd953ddca90. With the fix of the initial state for the cloned event we now correctly handle the error described in: 1f9a7268c67f perf: Do not allow optimized switch for non-cloned events so we can revert it. I made an automated test for this, but its not suitable for automated perf tests framework. It needs to be customized for each machine (the more cpu the higher numbers for GROUPS/WORKERS/BYTES) and it could take longer time to hit the issue. Signed-off-by: Jiri Olsa Signed-off-by: Peter Zijlstra (Intel) Cc: Frederic Weisbecker Cc: Stephane Eranian Cc: Jiri Olsa Cc: Arnaldo Carvalho de Melo Cc: Linus Torvalds Link: http://lkml.kernel.org/r/20140910143535.GD2409@krava.brq.redhat.com Signed-off-by: Ingo Molnar