linux/kernel/events, branch v4.6

perf/core: Disable the event on a truncated AUX record

2016-05-12T12:46:11Z

When the PMU driver reports a truncated AUX record, it effectively means that there is no more usable room in the event's AUX buffer (even though there may still be some room, so that perf_aux_output_begin() doesn't take action). At this point the consumer still has to be woken up and the event has to be disabled, otherwise the event will just keep spinning between perf_aux_output_begin() and perf_aux_output_end() until its context gets unscheduled. Again, for cpu-wide events this means never, so once in this condition, they will be forever losing data. Fix this by disabling the event and waking up the consumer in case of a truncated AUX record. Reported-by: Markus Metzger Signed-off-by: Alexander Shishkin Signed-off-by: Peter Zijlstra (Intel) Cc: Cc: Arnaldo Carvalho de Melo Cc: Arnaldo Carvalho de Melo Cc: Borislav Petkov Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: vince@deater.net Link: http://lkml.kernel.org/r/1462886313-13660-3-git-send-email-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar

perf/core: Change the default paranoia level to 2

2016-05-10T00:57:12Z

Allowing unprivileged kernel profiling lets any user dump follow kernel control flow and dump kernel registers. This most likely allows trivial kASLR bypassing, and it may allow other mischief as well. (Off the top of my head, the PERF_SAMPLE_REGS_INTR output during /dev/urandom reads could be quite interesting.) Signed-off-by: Andy Lutomirski Acked-by: Kees Cook Signed-off-by: Linus Torvalds

perf/core: Fix perf_event_open() vs. execve() race

2016-04-28T08:32:41Z

Jann reported that the ptrace_may_access() check in find_lively_task_by_vpid() is racy against exec(). Specifically: perf_event_open() execve() ptrace_may_access() commit_creds() ... if (get_dumpable() != SUID_DUMP_USER) perf_event_exit_task(); perf_install_in_context() would result in installing a counter across the creds boundary. Fix this by wrapping lots of perf_event_open() in cred_guard_mutex. This should be fine as perf_event_exit_task() is already called with cred_guard_mutex held, so all perf locks already nest inside it. Reported-by: Jann Horn Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Signed-off-by: Ingo Molnar

perf/core: Make sysctl_perf_cpu_time_max_percent conform to documentation

2016-04-23T11:47:50Z

Markus reported that 0 should also disable the throttling we per Documentation/sysctl/kernel.txt. Reported-by: Markus Trippelsdorf Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Fixes: 91a612eea9a3 ("perf/core: Fix dynamic interrupt throttle") Signed-off-by: Ingo Molnar

Merge branch 'PAGE_CACHE_SIZE-removal'

2016-04-04T17:50:24Z

Merge PAGE_CACHE_SIZE removal patches from Kirill Shutemov: "PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. Let's stop pretending that pages in page cache are special. They are not. The first patch with most changes has been done with coccinelle. The second is manual fixups on top. The third patch removes macros definition" [ I was planning to apply this just before rc2, but then I spaced out, so here it is right _after_ rc2 instead. As Kirill suggested as a possibility, I could have decided to only merge the first two patches, and leave the old interfaces for compatibility, but I'd rather get it all done and any out-of-tree modules and patches can trivially do the converstion while still also working with older kernels, so there is little reason to try to maintain the redundant legacy model. - Linus ] * PAGE_CACHE_SIZE-removal: mm: drop PAGE_CACHE_* and page_cache_{get,release} definition mm, fs: remove remaining PAGE_CACHE_* and page_cache_{get,release} usage mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros

mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros

2016-04-04T17:41:08Z

PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> ; - >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> ; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov Acked-by: Michal Hocko Signed-off-by: Linus Torvalds

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

2016-04-03T12:22:12Z

Pull perf fixes from Ingo Molnar: "Misc kernel side fixes: - fix event leak - fix AMD PMU driver bug - fix core event handling bug - fix build bug on certain randconfigs Plus misc tooling fixes" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/x86/amd/ibs: Fix pmu::stop() nesting perf/core: Don't leak event in the syscall error path perf/core: Fix time tracking bug with multiplexing perf jit: genelf makes assumptions about endian perf hists: Fix determination of a callchain node's childlessness perf tools: Add missing initialization of perf_sample.cpumode in synthesized samples perf tools: Fix build break on powerpc perf/x86: Move events_sysfs_show() outside CPU_SUP_INTEL perf bench: Fix detached tarball building due to missing 'perf bench memcpy' headers perf tests: Fix tarpkg build test error output redirection

perf/core: Don't leak event in the syscall error path

2016-03-31T07:54:07Z

In the error path, event_file not being NULL is used to determine whether the event itself still needs to be free'd, so fix it up to avoid leaking. Reported-by: Leon Yu Signed-off-by: Alexander Shishkin Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho de Melo Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Fixes: 130056275ade ("perf: Do not double free") Link: http://lkml.kernel.org/r/87twk06yxp.fsf@ashishki-desk.ger.corp.intel.com Signed-off-by: Ingo Molnar

perf/core: Fix time tracking bug with multiplexing

2016-03-31T07:54:06Z

Stephane reported that commit: 3cbaa5906967 ("perf: Fix ctx time tracking by introducing EVENT_TIME") introduced a regression wrt. time tracking, as easily observed by: > This patch introduce a bug in the time tracking of events when > multiplexing is used. > > The issue is easily reproducible with the following perf run: > > $ perf stat -a -C 0 -e branches,branches,branches,branches,branches,branches -I 1000 > 1.000730239 652,394 branches (66.41%) > 1.000730239 597,809 branches (66.41%) > 1.000730239 593,870 branches (66.63%) > 1.000730239 651,440 branches (67.03%) > 1.000730239 656,725 branches (66.96%) > 1.000730239 branches > > One branches event is shown as not having run. Yet, with > multiplexing, all events should run especially with a 1s (-I 1000) > interval. The delta for time_running comes out to 0. Yet, the event > has run because the kernel is actually multiplexing the events. The > problem is that the time tracking is the kernel and especially in > ctx_sched_out() is wrong now. > > The problem is that in case that the kernel enters ctx_sched_out() with the > following state: > ctx->is_active=0x7 event_type=0x1 > Call Trace: > [] dump_stack+0x63/0x82 > [] ctx_sched_out+0x2bc/0x2d0 > [] perf_mux_hrtimer_handler+0xf6/0x2c0 > [] ? __perf_install_in_context+0x130/0x130 > [] __hrtimer_run_queues+0xf8/0x2f0 > [] hrtimer_interrupt+0xb7/0x1d0 > [] local_apic_timer_interrupt+0x38/0x60 > [] smp_apic_timer_interrupt+0x3d/0x50 > [] apic_timer_interrupt+0x8c/0xa0 > > In that case, the test: > if (is_active & EVENT_TIME) > > will be false and the time will not be updated. Time must always be updated on > sched out. Fix this by always updating time if EVENT_TIME was set, as opposed to only updating time when EVENT_TIME changed. Reported-by: Stephane Eranian Tested-by: Stephane Eranian Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vince Weaver Cc: kan.liang@intel.com Cc: namhyung@kernel.org Fixes: 3cbaa5906967 ("perf: Fix ctx time tracking by introducing EVENT_TIME") Link: http://lkml.kernel.org/r/20160329072644.GB3408@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar

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

2016-03-24T17:02:14Z

Pull perf fixes from Ingo Molnar: "This tree contains various perf fixes on the kernel side, plus three hw/event-enablement late additions: - Intel Memory Bandwidth Monitoring events and handling - the AMD Accumulated Power Mechanism reporting facility - more IOMMU events ... and a final round of perf tooling updates/fixes" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (44 commits) perf llvm: Use strerror_r instead of the thread unsafe strerror one perf llvm: Use realpath to canonicalize paths perf tools: Unexport some methods unused outside strbuf.c perf probe: No need to use formatting strbuf method perf help: Use asprintf instead of adhoc equivalents perf tools: Remove unused perf_pathdup, xstrdup functions perf tools: Do not include stringify.h from the kernel sources tools include: Copy linux/stringify.h from the kernel tools lib traceevent: Remove redundant CPU output perf tools: Remove needless 'extern' from function prototypes perf tools: Simplify die() mechanism perf tools: Remove unused DIE_IF macro perf script: Remove lots of unused arguments perf thread: Rename perf_event__preprocess_sample_addr to thread__resolve perf machine: Rename perf_event__preprocess_sample to machine__resolve perf tools: Add cpumode to struct perf_sample perf tests: Forward the perf_sample in the dwarf unwind test perf tools: Remove misplaced __maybe_unused perf list: Fix documentation of :ppp perf bench numa: Fix assertion for nodes bitfield ...