1. 15 Aug, 2018 1 commit
    • Linus Torvalds's avatar
      init: rename and re-order boot_cpu_state_init() · b7722f4a
      Linus Torvalds authored
      commit b5b1404d upstream.
      
      This is purely a preparatory patch for upcoming changes during the 4.19
      merge window.
      
      We have a function called "boot_cpu_state_init()" that isn't really
      about the bootup cpu state: that is done much earlier by the similarly
      named "boot_cpu_init()" (note lack of "state" in name).
      
      This function initializes some hotplug CPU state, and needs to run after
      the percpu data has been properly initialized.  It even has a comment to
      that effect.
      
      Except it _doesn't_ actually run after the percpu data has been properly
      initialized.  On x86 it happens to do that, but on at least arm and
      arm64, the percpu base pointers are initialized by the arch-specific
      'smp_prepare_boot_cpu()' hook, which ran _after_ boot_cpu_state_init().
      
      This had some unexpected results, and in particular we have a patch
      pending for the merge window that did the obvious cleanup of using
      'this_cpu_write()' in the cpu hotplug init code:
      
        -       per_cpu_ptr(&cpuhp_state, smp_processor_id())->state = CPUHP_ONLINE;
        +       this_cpu_write(cpuhp_state.state, CPUHP_ONLINE);
      
      which is obviously the right thing to do.  Except because of the
      ordering issue, it actually failed miserably and unexpectedly on arm64.
      
      So this just fixes the ordering, and changes the name of the function to
      be 'boot_cpu_hotplug_init()' to make it obvious that it's about cpu
      hotplug state, because the core CPU state was supposed to have already
      been done earlier.
      
      Marked for stable, since the (not yet merged) patch that will show this
      problem is marked for stable.
      Reported-by: default avatarVlastimil Babka <vbabka@suse.cz>
      Reported-by: default avatarMian Yousaf Kaukab <yousaf.kaukab@suse.com>
      Suggested-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
      Acked-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: stable@kernel.org
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b7722f4a
  2. 20 Jun, 2018 1 commit
  3. 22 Feb, 2018 2 commits
  4. 31 Jan, 2018 1 commit
    • Alexei Starovoitov's avatar
      bpf: introduce BPF_JIT_ALWAYS_ON config · 6fde36d5
      Alexei Starovoitov authored
      [ upstream commit 290af866 ]
      
      The BPF interpreter has been used as part of the spectre 2 attack CVE-2017-5715.
      
      A quote from goolge project zero blog:
      "At this point, it would normally be necessary to locate gadgets in
      the host kernel code that can be used to actually leak data by reading
      from an attacker-controlled location, shifting and masking the result
      appropriately and then using the result of that as offset to an
      attacker-controlled address for a load. But piecing gadgets together
      and figuring out which ones work in a speculation context seems annoying.
      So instead, we decided to use the eBPF interpreter, which is built into
      the host kernel - while there is no legitimate way to invoke it from inside
      a VM, the presence of the code in the host kernel's text section is sufficient
      to make it usable for the attack, just like with ordinary ROP gadgets."
      
      To make attacker job harder introduce BPF_JIT_ALWAYS_ON config
      option that removes interpreter from the kernel in favor of JIT-only mode.
      So far eBPF JIT is supported by:
      x64, arm64, arm32, sparc64, s390, powerpc64, mips64
      
      The start of JITed program is randomized and code page is marked as read-only.
      In addition "constant blinding" can be turned on with net.core.bpf_jit_harden
      
      v2->v3:
      - move __bpf_prog_ret0 under ifdef (Daniel)
      
      v1->v2:
      - fix init order, test_bpf and cBPF (Daniel's feedback)
      - fix offloaded bpf (Jakub's feedback)
      - add 'return 0' dummy in case something can invoke prog->bpf_func
      - retarget bpf tree. For bpf-next the patch would need one extra hunk.
        It will be sent when the trees are merged back to net-next
      
      Considered doing:
        int bpf_jit_enable __read_mostly = BPF_EBPF_JIT_DEFAULT;
      but it seems better to land the patch as-is and in bpf-next remove
      bpf_jit_enable global variable from all JITs, consolidate in one place
      and remove this jit_init() function.
      Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      6fde36d5
  5. 02 Jan, 2018 1 commit
    • Thomas Gleixner's avatar
      x86/mm/pti: Add infrastructure for page table isolation · a4b07fb4
      Thomas Gleixner authored
      commit aa8c6248 upstream.
      
      Add the initial files for kernel page table isolation, with a minimal init
      function and the boot time detection for this misfeature.
      Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Dave Hansen <dave.hansen@linux.intel.com>
      Cc: David Laight <David.Laight@aculab.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: Eduardo Valentin <eduval@amazon.com>
      Cc: Greg KH <gregkh@linuxfoundation.org>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Juergen Gross <jgross@suse.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: aliguori@amazon.com
      Cc: daniel.gruss@iaik.tugraz.at
      Cc: hughd@google.com
      Cc: keescook@google.com
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      a4b07fb4
  6. 29 Dec, 2017 1 commit
  7. 02 Nov, 2017 1 commit
    • Greg Kroah-Hartman's avatar
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      Greg Kroah-Hartman authored
      Many source files in the tree are missing licensing information, which
      makes it harder for compliance tools to determine the correct license.
      
      By default all files without license information are under the default
      license of the kernel, which is GPL version 2.
      
      Update the files which contain no license information with the 'GPL-2.0'
      SPDX license identifier.  The SPDX identifier is a legally binding
      shorthand, which can be used instead of the full boiler plate text.
      
      This patch is based on work done by Thomas Gleixner and Kate Stewart and
      Philippe Ombredanne.
      
      How this work was done:
      
      Patches were generated and checked against linux-4.14-rc6 for a subset of
      the use cases:
       - file had no licensing information it it.
       - file was a */uapi/* one with no licensing information in it,
       - file was a */uapi/* one with existing licensing information,
      
      Further patches will be generated in subsequent months to fix up cases
      where non-standard license headers were used, and references to license
      had to be inferred by heuristics based on keywords.
      
      The analysis to determine which SPDX License Identifier to be applied to
      a file was done in a spreadsheet of side by side results from of the
      output of two independent scanners (ScanCode & Windriver) producing SPDX
      tag:value files created by Philippe Ombredanne.  Philippe prepared the
      base worksheet, and did an initial spot review of a few 1000 files.
      
      The 4.13 kernel was the starting point of the analysis with 60,537 files
      assessed.  Kate Stewart did a file by file comparison of the scanner
      results in the spreadsheet to determine which SPDX license identifier(s)
      to be applied to the file. She confirmed any determination that was not
      immediately clear with lawyers working with the Linux Foundation.
      
      Criteria used to select files for SPDX license identifier tagging was:
       - Files considered eligible had to be source code files.
       - Make and config files were included as candidates if they contained >5
         lines of source
       - File already had some variant of a license header in it (even if <5
         lines).
      
      All documentation files were explicitly excluded.
      
      The following heuristics were used to determine which SPDX license
      identifiers to apply.
      
       - when both scanners couldn't find any license traces, file was
         considered to have no license information in it, and the top level
         COPYING file license applied.
      
         For non */uapi/* files that summary was:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|-------
         GPL-2.0                                              11139
      
         and resulted in the first patch in this series.
      
         If that file was a */uapi/* path one, it was "GPL-2.0 WITH
         Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|-------
         GPL-2.0 WITH Linux-syscall-note                        930
      
         and resulted in the second patch in this series.
      
       - if a file had some form of licensing information in it, and was one
         of the */uapi/* ones, it was denoted with the Linux-syscall-note if
         any GPL family license was found in the file or had no licensing in
         it (per prior point).  Results summary:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|------
         GPL-2.0 WITH Linux-syscall-note                       270
         GPL-2.0+ WITH Linux-syscall-note                      169
         ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
         ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
         LGPL-2.1+ WITH Linux-syscall-note                      15
         GPL-1.0+ WITH Linux-syscall-note                       14
         ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
         LGPL-2.0+ WITH Linux-syscall-note                       4
         LGPL-2.1 WITH Linux-syscall-note                        3
         ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
         ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1
      
         and that resulted in the third patch in this series.
      
       - when the two scanners agreed on the detected license(s), that became
         the concluded license(s).
      
       - when there was disagreement between the two scanners (one detected a
         license but the other didn't, or they both detected different
         licenses) a manual inspection of the file occurred.
      
       - In most cases a manual inspection of the information in the file
         resulted in a clear resolution of the license that should apply (and
         which scanner probably needed to revisit its heuristics).
      
       - When it was not immediately clear, the license identifier was
         confirmed with lawyers working with the Linux Foundation.
      
       - If there was any question as to the appropriate license identifier,
         the file was flagged for further research and to be revisited later
         in time.
      
      In total, over 70 hours of logged manual review was done on the
      spreadsheet to determine the SPDX license identifiers to apply to the
      source files by Kate, Philippe, Thomas and, in some cases, confirmation
      by lawyers working with the Linux Foundation.
      
      Kate also obtained a third independent scan of the 4.13 code base from
      FOSSology, and compared selected files where the other two scanners
      disagreed against that SPDX file, to see if there was new insights.  The
      Windriver scanner is based on an older version of FOSSology in part, so
      they are related.
      
      Thomas did random spot checks in about 500 files from the spreadsheets
      for the uapi headers and agreed with SPDX license identifier in the
      files he inspected. For the non-uapi files Thomas did random spot checks
      in about 15000 files.
      
      In initial set of patches against 4.14-rc6, 3 files were found to have
      copy/paste license identifier errors, and have been fixed to reflect the
      correct identifier.
      
      Additionally Philippe spent 10 hours this week doing a detailed manual
      inspection and review of the 12,461 patched files from the initial patch
      version early this week with:
       - a full scancode scan run, collecting the matched texts, detected
         license ids and scores
       - reviewing anything where there was a license detected (about 500+
         files) to ensure that the applied SPDX license was correct
       - reviewing anything where there was no detection but the patch license
         was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
         SPDX license was correct
      
      This produced a worksheet with 20 files needing minor correction.  This
      worksheet was then exported into 3 different .csv files for the
      different types of files to be modified.
      
      These .csv files were then reviewed by Greg.  Thomas wrote a script to
      parse the csv files and add the proper SPDX tag to the file, in the
      format that the file expected.  This script was further refined by Greg
      based on the output to detect more types of files automatically and to
      distinguish between header and source .c files (which need different
      comment types.)  Finally Greg ran the script using the .csv files to
      generate the patches.
      Reviewed-by: default avatarKate Stewart <kstewart@linuxfoundation.org>
      Reviewed-by: default avatarPhilippe Ombredanne <pombredanne@nexb.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b2441318
  8. 07 Oct, 2017 1 commit
  9. 09 Sep, 2017 2 commits
    • Daniel Micay's avatar
      init/main.c: extract early boot entropy from the passed cmdline · 33d72f38
      Daniel Micay authored
      Feed the boot command-line as to the /dev/random entropy pool
      
      Existing Android bootloaders usually pass data which may not be known by
      an external attacker on the kernel command-line.  It may also be the
      case on other embedded systems.  Sample command-line from a Google Pixel
      running CopperheadOS....
      
          console=ttyHSL0,115200,n8 androidboot.console=ttyHSL0
          androidboot.hardware=sailfish user_debug=31 ehci-hcd.park=3
          lpm_levels.sleep_disabled=1 cma=32M@0-0xffffffff buildvariant=user
          veritykeyid=id:dfcb9db0089e5b3b4090a592415c28e1cb4545ab
          androidboot.bootdevice=624000.ufshc androidboot.verifiedbootstate=yellow
          androidboot.veritymode=enforcing androidboot.keymaster=1
          androidboot.serialno=FA6CE0305299 androidboot.baseband=msm
          mdss_mdp.panel=1:dsi:0:qcom,mdss_dsi_samsung_ea8064tg_1080p_cmd:1:none:cfg:single_dsi
          androidboot.slot_suffix=_b fpsimd.fpsimd_settings=0
          app_setting.use_app_setting=0 kernelflag=0x00000000 debugflag=0x00000000
          androidboot.hardware.revision=PVT radioflag=0x00000000
          radioflagex1=0x00000000 radioflagex2=0x00000000 cpumask=0x00000000
          androidboot.hardware.ddr=4096MB,Hynix,LPDDR4 androidboot.ddrinfo=00000006
          androidboot.ddrsize=4GB androidboot.hardware.color=GRA00
          androidboot.hardware.ufs=32GB,Samsung androidboot.msm.hw_ver_id=268824801
          androidboot.qf.st=2 androidboot.cid=11111111 androidboot.mid=G-2PW4100
          androidboot.bootloader=8996-012001-1704121145
          androidboot.oem_unlock_support=1 androidboot.fp_src=1
          androidboot.htc.hrdump=detected androidboot.ramdump.opt=mem@2g:2g,mem@4g:2g
          androidboot.bootreason=reboot androidboot.ramdump_enable=0 ro
          root=/dev/dm-0 dm="system none ro,0 1 android-verity /dev/sda34"
          rootwait skip_initramfs init=/init androidboot.wificountrycode=US
          androidboot.boottime=1BLL:85,1BLE:669,2BLL:0,2BLE:1777,SW:6,KL:8136
      
      Among other things, it contains a value unique to the device
      (androidboot.serialno=FA6CE0305299), unique to the OS builds for the
      device variant (veritykeyid=id:dfcb9db0089e5b3b4090a592415c28e1cb4545ab)
      and timings from the bootloader stages in milliseconds
      (androidboot.boottime=1BLL:85,1BLE:669,2BLL:0,2BLE:1777,SW:6,KL:8136).
      
      [tytso@mit.edu: changelog tweak]
      [labbott@redhat.com: line-wrapped command line]
      Link: http://lkml.kernel.org/r/20170816231458.2299-3-labbott@redhat.comSigned-off-by: default avatarDaniel Micay <danielmicay@gmail.com>
      Signed-off-by: default avatarLaura Abbott <labbott@redhat.com>
      Acked-by: default avatarKees Cook <keescook@chromium.org>
      Cc: "Theodore Ts'o" <tytso@mit.edu>
      Cc: Laura Abbott <lauraa@codeaurora.org>
      Cc: Nick Kralevich <nnk@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      33d72f38
    • Laura Abbott's avatar
      init: move stack canary initialization after setup_arch · 121388a3
      Laura Abbott authored
      Patch series "Command line randomness", v3.
      
      A series to add the kernel command line as a source of randomness.
      
      This patch (of 2):
      
      Stack canary intialization involves getting a random number.  Getting this
      random number may involve accessing caches or other architectural specific
      features which are not available until after the architecture is setup.
      Move the stack canary initialization later to accommodate this.
      
      Link: http://lkml.kernel.org/r/20170816231458.2299-2-labbott@redhat.comSigned-off-by: default avatarLaura Abbott <lauraa@codeaurora.org>
      Signed-off-by: default avatarLaura Abbott <labbott@redhat.com>
      Acked-by: default avatarKees Cook <keescook@chromium.org>
      Cc: "Theodore Ts'o" <tytso@mit.edu>
      Cc: Daniel Micay <danielmicay@gmail.com>
      Cc: Nick Kralevich <nnk@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      121388a3
  10. 07 Sep, 2017 2 commits
    • Michal Hocko's avatar
      mm, memory_hotplug: drop zone from build_all_zonelists · 72675e13
      Michal Hocko authored
      build_all_zonelists gets a zone parameter to initialize zone's pagesets.
      There is only a single user which gives a non-NULL zone parameter and
      that one doesn't really need the rest of the build_all_zonelists (see
      commit 6dcd73d7 ("memory-hotplug: allocate zone's pcp before
      onlining pages")).
      
      Therefore remove setup_zone_pageset from build_all_zonelists and call it
      from its only user directly.  This will also remove a pointless zonlists
      rebuilding which is always good.
      
      Link: http://lkml.kernel.org/r/20170721143915.14161-5-mhocko@kernel.orgSigned-off-by: default avatarMichal Hocko <mhocko@suse.com>
      Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Joonsoo Kim <js1304@gmail.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Shaohua Li <shaohua.li@intel.com>
      Cc: Toshi Kani <toshi.kani@hpe.com>
      Cc: Wen Congyang <wency@cn.fujitsu.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      72675e13
    • Kees Cook's avatar
      mm: add SLUB free list pointer obfuscation · 2482ddec
      Kees Cook authored
      This SLUB free list pointer obfuscation code is modified from Brad
      Spengler/PaX Team's code in the last public patch of grsecurity/PaX
      based on my understanding of the code.  Changes or omissions from the
      original code are mine and don't reflect the original grsecurity/PaX
      code.
      
      This adds a per-cache random value to SLUB caches that is XORed with
      their freelist pointer address and value.  This adds nearly zero
      overhead and frustrates the very common heap overflow exploitation
      method of overwriting freelist pointers.
      
      A recent example of the attack is written up here:
      
        http://cyseclabs.com/blog/cve-2016-6187-heap-off-by-one-exploit
      
      and there is a section dedicated to the technique the book "A Guide to
      Kernel Exploitation: Attacking the Core".
      
      This is based on patches by Daniel Micay, and refactored to minimize the
      use of #ifdef.
      
      With 200-count cycles of "hackbench -g 20 -l 1000" I saw the following
      run times:
      
       before:
       	mean 10.11882499999999999995
      	variance .03320378329145728642
      	stdev .18221905304181911048
      
        after:
      	mean 10.12654000000000000014
      	variance .04700556623115577889
      	stdev .21680767106160192064
      
      The difference gets lost in the noise, but if the above is to be taken
      literally, using CONFIG_FREELIST_HARDENED is 0.07% slower.
      
      Link: http://lkml.kernel.org/r/20170802180609.GA66807@beastSigned-off-by: default avatarKees Cook <keescook@chromium.org>
      Suggested-by: default avatarDaniel Micay <danielmicay@gmail.com>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Tycho Andersen <tycho@docker.com>
      Cc: Alexander Popov <alex.popov@linux.com>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2482ddec
  11. 04 Sep, 2017 1 commit
  12. 14 Aug, 2017 1 commit
    • Waiman Long's avatar
      debugobjects: Make kmemleak ignore debug objects · caba4cbb
      Waiman Long authored
      The allocated debug objects are either on the free list or in the
      hashed bucket lists. So they won't get lost. However if both debug
      objects and kmemleak are enabled and kmemleak scanning is done
      while some of the debug objects are transitioning from one list to
      the others, false negative reporting of memory leaks may happen for
      those objects. For example,
      
      [38687.275678] kmemleak: 12 new suspected memory leaks (see
      /sys/kernel/debug/kmemleak)
      unreferenced object 0xffff92e98aabeb68 (size 40):
        comm "ksmtuned", pid 4344, jiffies 4298403600 (age 906.430s)
        hex dump (first 32 bytes):
          00 00 00 00 00 00 00 00 d0 bc db 92 e9 92 ff ff  ................
          01 00 00 00 00 00 00 00 38 36 8a 61 e9 92 ff ff  ........86.a....
        backtrace:
          [<ffffffff8fa5378a>] kmemleak_alloc+0x4a/0xa0
          [<ffffffff8f47c019>] kmem_cache_alloc+0xe9/0x320
          [<ffffffff8f62ed96>] __debug_object_init+0x3e6/0x400
          [<ffffffff8f62ef01>] debug_object_activate+0x131/0x210
          [<ffffffff8f330d9f>] __call_rcu+0x3f/0x400
          [<ffffffff8f33117d>] call_rcu_sched+0x1d/0x20
          [<ffffffff8f4a183c>] put_object+0x2c/0x40
          [<ffffffff8f4a188c>] __delete_object+0x3c/0x50
          [<ffffffff8f4a18bd>] delete_object_full+0x1d/0x20
          [<ffffffff8fa535c2>] kmemleak_free+0x32/0x80
          [<ffffffff8f47af07>] kmem_cache_free+0x77/0x350
          [<ffffffff8f453912>] unlink_anon_vmas+0x82/0x1e0
          [<ffffffff8f440341>] free_pgtables+0xa1/0x110
          [<ffffffff8f44af91>] exit_mmap+0xc1/0x170
          [<ffffffff8f29db60>] mmput+0x80/0x150
          [<ffffffff8f2a7609>] do_exit+0x2a9/0xd20
      
      The references in the debug objects may also hide a real memory leak.
      
      As there is no point in having kmemleak to track debug object
      allocations, kmemleak checking is now disabled for debug objects.
      Signed-off-by: default avatarWaiman Long <longman@redhat.com>
      Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Link: http://lkml.kernel.org/r/1502718733-8527-1-git-send-email-longman@redhat.com
      caba4cbb
  13. 10 Aug, 2017 1 commit
  14. 01 Aug, 2017 1 commit
  15. 26 Jul, 2017 1 commit
    • Dennis Zhou (Facebook)'s avatar
      percpu: replace area map allocator with bitmap · 40064aec
      Dennis Zhou (Facebook) authored
      The percpu memory allocator is experiencing scalability issues when
      allocating and freeing large numbers of counters as in BPF.
      Additionally, there is a corner case where iteration is triggered over
      all chunks if the contig_hint is the right size, but wrong alignment.
      
      This patch replaces the area map allocator with a basic bitmap allocator
      implementation. Each subsequent patch will introduce new features and
      replace full scanning functions with faster non-scanning options when
      possible.
      
      Implementation:
      This patchset removes the area map allocator in favor of a bitmap
      allocator backed by metadata blocks. The primary goal is to provide
      consistency in performance and memory footprint with a focus on small
      allocations (< 64 bytes). The bitmap removes the heavy memmove from the
      freeing critical path and provides a consistent memory footprint. The
      metadata blocks provide a bound on the amount of scanning required by
      maintaining a set of hints.
      
      In an effort to make freeing fast, the metadata is updated on the free
      path if the new free area makes a page free, a block free, or spans
      across blocks. This causes the chunk's contig hint to potentially be
      smaller than what it could allocate by up to the smaller of a page or a
      block. If the chunk's contig hint is contained within a block, a check
      occurs and the hint is kept accurate. Metadata is always kept accurate
      on allocation, so there will not be a situation where a chunk has a
      later contig hint than available.
      
      Evaluation:
      I have primarily done testing against a simple workload of allocation of
      1 million objects (2^20) of varying size. Deallocation was done by in
      order, alternating, and in reverse. These numbers were collected after
      rebasing ontop of a80099a1. I present the worst-case numbers here:
      
        Area Map Allocator:
      
              Object Size | Alloc Time (ms) | Free Time (ms)
              ----------------------------------------------
                    4B    |        310      |     4770
                   16B    |        557      |     1325
                   64B    |        436      |      273
                  256B    |        776      |      131
                 1024B    |       3280      |      122
      
        Bitmap Allocator:
      
              Object Size | Alloc Time (ms) | Free Time (ms)
              ----------------------------------------------
                    4B    |        490      |       70
                   16B    |        515      |       75
                   64B    |        610      |       80
                  256B    |        950      |      100
                 1024B    |       3520      |      200
      
      This data demonstrates the inability for the area map allocator to
      handle less than ideal situations. In the best case of reverse
      deallocation, the area map allocator was able to perform within range
      of the bitmap allocator. In the worst case situation, freeing took
      nearly 5 seconds for 1 million 4-byte objects. The bitmap allocator
      dramatically improves the consistency of the free path. The small
      allocations performed nearly identical regardless of the freeing
      pattern.
      
      While it does add to the allocation latency, the allocation scenario
      here is optimal for the area map allocator. The area map allocator runs
      into trouble when it is allocating in chunks where the latter half is
      full. It is difficult to replicate this, so I present a variant where
      the pages are second half filled. Freeing was done sequentially. Below
      are the numbers for this scenario:
      
        Area Map Allocator:
      
              Object Size | Alloc Time (ms) | Free Time (ms)
              ----------------------------------------------
                    4B    |       4118      |     4892
                   16B    |       1651      |     1163
                   64B    |        598      |      285
                  256B    |        771      |      158
                 1024B    |       3034      |      160
      
        Bitmap Allocator:
      
              Object Size | Alloc Time (ms) | Free Time (ms)
              ----------------------------------------------
                    4B    |        481      |       67
                   16B    |        506      |       69
                   64B    |        636      |       75
                  256B    |        892      |       90
                 1024B    |       3262      |      147
      
      The data shows a parabolic curve of performance for the area map
      allocator. This is due to the memmove operation being the dominant cost
      with the lower object sizes as more objects are packed in a chunk and at
      higher object sizes, the traversal of the chunk slots is the dominating
      cost. The bitmap allocator suffers this problem as well. The above data
      shows the inability to scale for the allocation path with the area map
      allocator and that the bitmap allocator demonstrates consistent
      performance in general.
      
      The second problem of additional scanning can result in the area map
      allocator completing in 52 minutes when trying to allocate 1 million
      4-byte objects with 8-byte alignment. The same workload takes
      approximately 16 seconds to complete for the bitmap allocator.
      
      V2:
      Fixed a bug in pcpu_alloc_first_chunk end_offset was setting the bitmap
      using bytes instead of bits.
      
      Added a comment to pcpu_cnt_pop_pages to explain bitmap_weight.
      Signed-off-by: default avatarDennis Zhou <dennisszhou@gmail.com>
      Reviewed-by: default avatarJosef Bacik <jbacik@fb.com>
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      40064aec
  16. 18 Jul, 2017 1 commit
    • Tom Lendacky's avatar
      x86, swiotlb: Add memory encryption support · c7753208
      Tom Lendacky authored
      Since DMA addresses will effectively look like 48-bit addresses when the
      memory encryption mask is set, SWIOTLB is needed if the DMA mask of the
      device performing the DMA does not support 48-bits. SWIOTLB will be
      initialized to create decrypted bounce buffers for use by these devices.
      Signed-off-by: default avatarTom Lendacky <thomas.lendacky@amd.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Alexander Potapenko <glider@google.com>
      Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brijesh Singh <brijesh.singh@amd.com>
      Cc: Dave Young <dyoung@redhat.com>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      Cc: Larry Woodman <lwoodman@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Matt Fleming <matt@codeblueprint.co.uk>
      Cc: Michael S. Tsirkin <mst@redhat.com>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Radim Krčmář <rkrcmar@redhat.com>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Toshimitsu Kani <toshi.kani@hpe.com>
      Cc: kasan-dev@googlegroups.com
      Cc: kvm@vger.kernel.org
      Cc: linux-arch@vger.kernel.org
      Cc: linux-doc@vger.kernel.org
      Cc: linux-efi@vger.kernel.org
      Cc: linux-mm@kvack.org
      Link: http://lkml.kernel.org/r/aa2d29b78ae7d508db8881e46a3215231b9327a7.1500319216.git.thomas.lendacky@amd.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      c7753208
  17. 17 Jul, 2017 2 commits
    • David Howells's avatar
      VFS: Differentiate mount flags (MS_*) from internal superblock flags · e462ec50
      David Howells authored
      Differentiate the MS_* flags passed to mount(2) from the internal flags set
      in the super_block's s_flags.  s_flags are now called SB_*, with the names
      and the values for the moment mirroring the MS_* flags that they're
      equivalent to.
      
      In this patch, just the headers are altered and some kernel code where
      blind automated conversion isn't necessarily correct.
      
      Note that this shows up some interesting issues:
      
       (1) Some MS_* flags get translated to MNT_* flags (such as MS_NODEV ->
           MNT_NODEV) without passing this on to the filesystem, but some
           filesystems set such flags anyway.
      
       (2) The ->remount_fs() methods of some filesystems adjust the *flags
           argument by setting MS_* flags in it, such as MS_NOATIME - but these
           flags are then scrubbed by do_remount_sb() (only the occupants of
           MS_RMT_MASK are permitted: MS_RDONLY, MS_SYNCHRONOUS, MS_MANDLOCK,
           MS_I_VERSION and MS_LAZYTIME)
      
      I'm not sure what's the best way to solve all these cases.
      Suggested-by: default avatarAl Viro <viro@ZenIV.linux.org.uk>
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      e462ec50
    • David Howells's avatar
      VFS: Convert sb->s_flags & MS_RDONLY to sb_rdonly(sb) · bc98a42c
      David Howells authored
      Firstly by applying the following with coccinelle's spatch:
      
      	@@ expression SB; @@
      	-SB->s_flags & MS_RDONLY
      	+sb_rdonly(SB)
      
      to effect the conversion to sb_rdonly(sb), then by applying:
      
      	@@ expression A, SB; @@
      	(
      	-(!sb_rdonly(SB)) && A
      	+!sb_rdonly(SB) && A
      	|
      	-A != (sb_rdonly(SB))
      	+A != sb_rdonly(SB)
      	|
      	-A == (sb_rdonly(SB))
      	+A == sb_rdonly(SB)
      	|
      	-!(sb_rdonly(SB))
      	+!sb_rdonly(SB)
      	|
      	-A && (sb_rdonly(SB))
      	+A && sb_rdonly(SB)
      	|
      	-A || (sb_rdonly(SB))
      	+A || sb_rdonly(SB)
      	|
      	-(sb_rdonly(SB)) != A
      	+sb_rdonly(SB) != A
      	|
      	-(sb_rdonly(SB)) == A
      	+sb_rdonly(SB) == A
      	|
      	-(sb_rdonly(SB)) && A
      	+sb_rdonly(SB) && A
      	|
      	-(sb_rdonly(SB)) || A
      	+sb_rdonly(SB) || A
      	)
      
      	@@ expression A, B, SB; @@
      	(
      	-(sb_rdonly(SB)) ? 1 : 0
      	+sb_rdonly(SB)
      	|
      	-(sb_rdonly(SB)) ? A : B
      	+sb_rdonly(SB) ? A : B
      	)
      
      to remove left over excess bracketage and finally by applying:
      
      	@@ expression A, SB; @@
      	(
      	-(A & MS_RDONLY) != sb_rdonly(SB)
      	+(bool)(A & MS_RDONLY) != sb_rdonly(SB)
      	|
      	-(A & MS_RDONLY) == sb_rdonly(SB)
      	+(bool)(A & MS_RDONLY) == sb_rdonly(SB)
      	)
      
      to make comparisons against the result of sb_rdonly() (which is a bool)
      work correctly.
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      bc98a42c
  18. 12 Jul, 2017 1 commit
    • Kees Cook's avatar
      random: do not ignore early device randomness · ee7998c5
      Kees Cook authored
      The add_device_randomness() function would ignore incoming bytes if the
      crng wasn't ready.  This additionally makes sure to make an early enough
      call to add_latent_entropy() to influence the initial stack canary,
      which is especially important on non-x86 systems where it stays the same
      through the life of the boot.
      
      Link: http://lkml.kernel.org/r/20170626233038.GA48751@beastSigned-off-by: default avatarKees Cook <keescook@chromium.org>
      Cc: "Theodore Ts'o" <tytso@mit.edu>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Jessica Yu <jeyu@redhat.com>
      Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
      Cc: Viresh Kumar <viresh.kumar@linaro.org>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Prarit Bhargava <prarit@redhat.com>
      Cc: Lokesh Vutla <lokeshvutla@ti.com>
      Cc: Nicholas Piggin <npiggin@gmail.com>
      Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ee7998c5
  19. 06 Jul, 2017 1 commit
    • Kees Cook's avatar
      mm: allow slab_nomerge to be set at build time · 7660a6fd
      Kees Cook authored
      Some hardened environments want to build kernels with slab_nomerge
      already set (so that they do not depend on remembering to set the kernel
      command line option).  This is desired to reduce the risk of kernel heap
      overflows being able to overwrite objects from merged caches and changes
      the requirements for cache layout control, increasing the difficulty of
      these attacks.  By keeping caches unmerged, these kinds of exploits can
      usually only damage objects in the same cache (though the risk to
      metadata exploitation is unchanged).
      
      Link: http://lkml.kernel.org/r/20170620230911.GA25238@beastSigned-off-by: default avatarKees Cook <keescook@chromium.org>
      Cc: Daniel Micay <danielmicay@gmail.com>
      Cc: David Windsor <dave@nullcore.net>
      Cc: Eric Biggers <ebiggers3@gmail.com>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: Daniel Micay <danielmicay@gmail.com>
      Cc: David Windsor <dave@nullcore.net>
      Cc: Eric Biggers <ebiggers3@gmail.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
      Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Daniel Mack <daniel@zonque.org>
      Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
      Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
      Cc: Helge Deller <deller@gmx.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Randy Dunlap <rdunlap@infradead.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7660a6fd
  20. 23 Jun, 2017 1 commit
  21. 14 Jun, 2017 1 commit
  22. 09 Jun, 2017 6 commits
  23. 08 Jun, 2017 1 commit
  24. 23 May, 2017 2 commits
  25. 09 May, 2017 2 commits
  26. 06 May, 2017 1 commit
    • Linus Torvalds's avatar
      initramfs: avoid "label at end of compound statement" error · 394e4f5d
      Linus Torvalds authored
      Commit 17a9be31 ("initramfs: Always do fput() and load modules after
      rootfs populate") introduced an error for the
      
          CONFIG_BLK_DEV_RAM=y
      
      case, because even though the code looks fine, the compiler really wants
      a statement after a label, or you'll get complaints:
      
        init/initramfs.c: In function 'populate_rootfs':
        init/initramfs.c:644:2: error: label at end of compound statement
      
      That commit moved the subsequent statements to outside the compound
      statement, leaving the label without any associated statements.
      Reported-by: default avatarJörg Otte <jrg.otte@gmail.com>
      Fixes: 17a9be31 ("initramfs: Always do fput() and load modules after rootfs populate")
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: Stafford Horne <shorne@gmail.com>
      Cc: stable@vger.kernel.org  # if 17a9be31 gets backported
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      394e4f5d
  27. 05 May, 2017 1 commit
    • Stafford Horne's avatar
      initramfs: Always do fput() and load modules after rootfs populate · 17a9be31
      Stafford Horne authored
      In OpenRISC we do not have a bootloader passed initrd, but the built in
      initramfs does contain the /init and other binaries, including modules.
      The previous commit 08865514 ("initramfs: finish fput() before
      accessing any binary from initramfs") made a change to only call fput()
      if the bootloader initrd was available, this caused intermittent crashes
      for OpenRISC.
      
      This patch changes the fput() to happen unconditionally if any rootfs is
      loaded. Also, I added some comments to make it a bit more clear why we
      call unpack_to_rootfs() multiple times.
      
      Fixes: 08865514 ("initramfs: finish fput() before accessing any binary from initramfs")
      Cc: stable@vger.kernel.org
      Cc: Lokesh Vutla <lokeshvutla@ti.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Acked-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      Signed-off-by: default avatarStafford Horne <shorne@gmail.com>
      17a9be31
  28. 02 May, 2017 1 commit
  29. 24 Apr, 2017 1 commit