pm24.git/kernel/events, branch v5.4-rc4

kernel/events/uprobes.c: only do FOLL_SPLIT_PMD for uprobe register

2019-10-19T10:32:33Z

Attaching uprobe to text section in THP splits the PMD mapped page table into PTE mapped entries. On uprobe detach, we would like to regroup PMD mapped page table entry to regain performance benefit of THP. However, the regroup is broken For perf_event based trace_uprobe. This is because perf_event based trace_uprobe calls uprobe_unregister twice on close: first in TRACE_REG_PERF_CLOSE, then in TRACE_REG_PERF_UNREGISTER. The second call will split the PMD mapped page table entry, which is not the desired behavior. Fix this by only use FOLL_SPLIT_PMD for uprobe register case. Add a WARN() to confirm uprobe unregister never work on huge pages, and abort the operation when this WARN() triggers. Link: http://lkml.kernel.org/r/20191017164223.2762148-6-songliubraving@fb.com Fixes: 5a52c9df62b4 ("uprobe: use FOLL_SPLIT_PMD instead of FOLL_SPLIT") Signed-off-by: Song Liu Reviewed-by: Srikar Dronamraju Cc: Kirill A. Shutemov Cc: Oleg Nesterov Cc: Matthew Wilcox (Oracle) Cc: William Kucharski Cc: Yang Shi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

perf/core: Fix corner case in perf_rotate_context()

2019-10-09T10:44:13Z

In perf_rotate_context(), when the first cpu flexible event fail to schedule, cpu_rotate is 1, while cpu_event is NULL. Since cpu_event is NULL, perf_rotate_context will _NOT_ call cpu_ctx_sched_out(), thus cpuctx->ctx.is_active will have EVENT_FLEXIBLE set. Then, the next perf_event_sched_in() will skip all cpu flexible events because of the EVENT_FLEXIBLE bit. In the next call of perf_rotate_context(), cpu_rotate stays 1, and cpu_event stays NULL, so this process repeats. The end result is, flexible events on this cpu will not be scheduled (until another event being added to the cpuctx). Here is an easy repro of this issue. On Intel CPUs, where ref-cycles could only use one counter, run one pinned event for ref-cycles, one flexible event for ref-cycles, and one flexible event for cycles. The flexible ref-cycles is never scheduled, which is expected. However, because of this issue, the cycles event is never scheduled either. $ perf stat -e ref-cycles:D,ref-cycles,cycles -C 5 -I 1000 time counts unit events 1.000152973 15,412,480 ref-cycles:D 1.000152973 ref-cycles (0.00%) 1.000152973 cycles (0.00%) 2.000486957 18,263,120 ref-cycles:D 2.000486957 ref-cycles (0.00%) 2.000486957 cycles (0.00%) To fix this, when the flexible_active list is empty, try rotate the first event in the flexible_groups. Also, rename ctx_first_active() to ctx_event_to_rotate(), which is more accurate. Signed-off-by: Song Liu Signed-off-by: Peter Zijlstra (Intel) Cc: Cc: Arnaldo Carvalho de Melo Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Sasha Levin Cc: Thomas Gleixner Fixes: 8d5bce0c37fa ("perf/core: Optimize perf_rotate_context() event scheduling") Link: https://lkml.kernel.org/r/20191008165949.920548-1-songliubraving@fb.com Signed-off-by: Ingo Molnar

perf/core: Rework memory accounting in perf_mmap()

2019-10-09T10:44:12Z

perf/core: Fix inheritance of aux_output groups

2019-10-07T14:50:42Z

Commit: ab43762ef010 ("perf: Allow normal events to output AUX data") forgets to configure aux_output relation in the inherited groups, which results in child PEBS events forever failing to schedule. Fix this by setting up the AUX output link in the inheritance path. Signed-off-by: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Peter Zijlstra Cc: Thomas Gleixner Link: https://lkml.kernel.org/r/20191004125729.32397-1-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar

perf_event_open: switch to copy_struct_from_user()

2019-10-01T13:45:22Z

Switch perf_event_open() syscall from it's own copying struct perf_event_attr from userspace to the new dedicated copy_struct_from_user() helper. The change is very straightforward, and helps unify the syscall interface for struct-from-userspace syscalls. Signed-off-by: Aleksa Sarai Reviewed-by: Kees Cook Reviewed-by: Christian Brauner [christian.brauner@ubuntu.com: improve commit message] Link: https://lore.kernel.org/r/20191001011055.19283-5-cyphar@cyphar.com Signed-off-by: Christian Brauner

Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

2019-09-28T15:14:15Z

Pull kernel lockdown mode from James Morris: "This is the latest iteration of the kernel lockdown patchset, from Matthew Garrett, David Howells and others. From the original description: This patchset introduces an optional kernel lockdown feature, intended to strengthen the boundary between UID 0 and the kernel. When enabled, various pieces of kernel functionality are restricted. Applications that rely on low-level access to either hardware or the kernel may cease working as a result - therefore this should not be enabled without appropriate evaluation beforehand. The majority of mainstream distributions have been carrying variants of this patchset for many years now, so there's value in providing a doesn't meet every distribution requirement, but gets us much closer to not requiring external patches. There are two major changes since this was last proposed for mainline: - Separating lockdown from EFI secure boot. Background discussion is covered here: https://lwn.net/Articles/751061/ - Implementation as an LSM, with a default stackable lockdown LSM module. This allows the lockdown feature to be policy-driven, rather than encoding an implicit policy within the mechanism. The new locked_down LSM hook is provided to allow LSMs to make a policy decision around whether kernel functionality that would allow tampering with or examining the runtime state of the kernel should be permitted. The included lockdown LSM provides an implementation with a simple policy intended for general purpose use. This policy provides a coarse level of granularity, controllable via the kernel command line: lockdown={integrity|confidentiality} Enable the kernel lockdown feature. If set to integrity, kernel features that allow userland to modify the running kernel are disabled. If set to confidentiality, kernel features that allow userland to extract confidential information from the kernel are also disabled. This may also be controlled via /sys/kernel/security/lockdown and overriden by kernel configuration. New or existing LSMs may implement finer-grained controls of the lockdown features. Refer to the lockdown_reason documentation in include/linux/security.h for details. The lockdown feature has had signficant design feedback and review across many subsystems. This code has been in linux-next for some weeks, with a few fixes applied along the way. Stephen Rothwell noted that commit 9d1f8be5cf42 ("bpf: Restrict bpf when kernel lockdown is in confidentiality mode") is missing a Signed-off-by from its author. Matthew responded that he is providing this under category (c) of the DCO" * 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (31 commits) kexec: Fix file verification on S390 security: constify some arrays in lockdown LSM lockdown: Print current->comm in restriction messages efi: Restrict efivar_ssdt_load when the kernel is locked down tracefs: Restrict tracefs when the kernel is locked down debugfs: Restrict debugfs when the kernel is locked down kexec: Allow kexec_file() with appropriate IMA policy when locked down lockdown: Lock down perf when in confidentiality mode bpf: Restrict bpf when kernel lockdown is in confidentiality mode lockdown: Lock down tracing and perf kprobes when in confidentiality mode lockdown: Lock down /proc/kcore x86/mmiotrace: Lock down the testmmiotrace module lockdown: Lock down module params that specify hardware parameters (eg. ioport) lockdown: Lock down TIOCSSERIAL lockdown: Prohibit PCMCIA CIS storage when the kernel is locked down acpi: Disable ACPI table override if the kernel is locked down acpi: Ignore acpi_rsdp kernel param when the kernel has been locked down ACPI: Limit access to custom_method when the kernel is locked down x86/msr: Restrict MSR access when the kernel is locked down x86: Lock down IO port access when the kernel is locked down ...

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

2019-09-26T22:38:07Z

Pull more perf updates from Ingo Molnar: "The only kernel change is comment typo fixes. The rest is mostly tooling fixes, but also new vendor event additions and updates, a bigger libperf/libtraceevent library and a header files reorganization that came in a bit late" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (108 commits) perf unwind: Fix libunwind build failure on i386 systems perf parser: Remove needless include directives perf build: Add detection of java-11-openjdk-devel package perf jvmti: Include JVMTI support for s390 perf vendor events: Remove P8 HW events which are not supported perf evlist: Fix access of freed id arrays perf stat: Fix free memory access / memory leaks in metrics perf tools: Replace needless mmap.h with what is needed, event.h perf evsel: Move config terms to a separate header perf evlist: Remove unused perf_evlist__fprintf() method perf evsel: Introduce evsel_fprintf.h perf evsel: Remove need for symbol_conf in evsel_fprintf.c perf copyfile: Move copyfile routines to separate files libperf: Add perf_evlist__poll() function libperf: Add perf_evlist__add_pollfd() function libperf: Add perf_evlist__alloc_pollfd() function libperf: Add libperf_init() call to the tests libperf: Merge libperf_set_print() into libperf_init() libperf: Add libperf dependency for tests targets libperf: Use sys/types.h to get ssize_t, not unistd.h ...

uprobe: collapse THP pmd after removing all uprobes

2019-09-24T22:54:11Z

After all uprobes are removed from the huge page (with PTE pgtable), it is possible to collapse the pmd and benefit from THP again. This patch does the collapse by calling collapse_pte_mapped_thp(). Link: http://lkml.kernel.org/r/20190815164525.1848545-7-songliubraving@fb.com Signed-off-by: Song Liu Acked-by: Kirill A. Shutemov Reported-by: kbuild test robot Reviewed-by: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

uprobe: use FOLL_SPLIT_PMD instead of FOLL_SPLIT

2019-09-24T22:54:11Z

Use the newly added FOLL_SPLIT_PMD in uprobe. This preserves the huge page when the uprobe is enabled. When the uprobe is disabled, newer instances of the same application could still benefit from huge page. For the next step, we will enable khugepaged to regroup the pmd, so that existing instances of the application could also benefit from huge page after the uprobe is disabled. Link: http://lkml.kernel.org/r/20190815164525.1848545-5-songliubraving@fb.com Signed-off-by: Song Liu Acked-by: Kirill A. Shutemov Reviewed-by: Srikar Dronamraju Reviewed-by: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

uprobe: use original page when all uprobes are removed

2019-09-24T22:54:11Z

Currently, uprobe swaps the target page with a anonymous page in both install_breakpoint() and remove_breakpoint(). When all uprobes on a page are removed, the given mm is still using an anonymous page (not the original page). This patch allows uprobe to use original page when possible (all uprobes on the page are already removed, and the original page is in page cache and uptodate). As suggested by Oleg, we unmap the old_page and let the original page fault in. Link: http://lkml.kernel.org/r/20190815164525.1848545-3-songliubraving@fb.com Signed-off-by: Song Liu Suggested-by: Oleg Nesterov Reviewed-by: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds