1. 06 Apr, 2018 2 commits
  2. 14 Feb, 2018 1 commit
  3. 07 Feb, 2018 8 commits
  4. 29 Nov, 2017 1 commit
  5. 16 Nov, 2017 1 commit
  6. 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: 's avatarKate Stewart <kstewart@linuxfoundation.org>
      Reviewed-by: 's avatarPhilippe Ombredanne <pombredanne@nexb.com>
      Reviewed-by: 's avatarThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: 's avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b2441318
  7. 02 Aug, 2017 1 commit
  8. 26 Jul, 2017 1 commit
  9. 10 Jul, 2017 5 commits
  10. 09 May, 2017 1 commit
  11. 03 May, 2017 9 commits
  12. 18 Apr, 2017 1 commit
    • Paul E. McKenney's avatar
      mm: Rename SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU · 5f0d5a3a
      Paul E. McKenney authored
      A group of Linux kernel hackers reported chasing a bug that resulted
      from their assumption that SLAB_DESTROY_BY_RCU provided an existence
      guarantee, that is, that no block from such a slab would be reallocated
      during an RCU read-side critical section.  Of course, that is not the
      case.  Instead, SLAB_DESTROY_BY_RCU only prevents freeing of an entire
      slab of blocks.
      
      However, there is a phrase for this, namely "type safety".  This commit
      therefore renames SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU in order
      to avoid future instances of this sort of confusion.
      Signed-off-by: 's avatarPaul E. McKenney <paulmck@linux.vnet.ibm.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>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: <linux-mm@kvack.org>
      Acked-by: 's avatarJohannes Weiner <hannes@cmpxchg.org>
      Acked-by: 's avatarVlastimil Babka <vbabka@suse.cz>
      [ paulmck: Add comments mentioning the old name, as requested by Eric
        Dumazet, in order to help people familiar with the old name find
        the new one. ]
      Acked-by: 's avatarDavid Rientjes <rientjes@google.com>
      5f0d5a3a
  13. 01 Apr, 2017 1 commit
  14. 10 Mar, 2017 2 commits
    • Dmitry Vyukov's avatar
      kasan: fix races in quarantine_remove_cache() · ce5bec54
      Dmitry Vyukov authored
      quarantine_remove_cache() frees all pending objects that belong to the
      cache, before we destroy the cache itself.  However there are currently
      two possibilities how it can fail to do so.
      
      First, another thread can hold some of the objects from the cache in
      temp list in quarantine_put().  quarantine_put() has a windows of
      enabled interrupts, and on_each_cpu() in quarantine_remove_cache() can
      finish right in that window.  These objects will be later freed into the
      destroyed cache.
      
      Then, quarantine_reduce() has the same problem.  It grabs a batch of
      objects from the global quarantine, then unlocks quarantine_lock and
      then frees the batch.  quarantine_remove_cache() can finish while some
      objects from the cache are still in the local to_free list in
      quarantine_reduce().
      
      Fix the race with quarantine_put() by disabling interrupts for the whole
      duration of quarantine_put().  In combination with on_each_cpu() in
      quarantine_remove_cache() it ensures that quarantine_remove_cache()
      either sees the objects in the per-cpu list or in the global list.
      
      Fix the race with quarantine_reduce() by protecting quarantine_reduce()
      with srcu critical section and then doing synchronize_srcu() at the end
      of quarantine_remove_cache().
      
      I've done some assessment of how good synchronize_srcu() works in this
      case.  And on a 4 CPU VM I see that it blocks waiting for pending read
      critical sections in about 2-3% of cases.  Which looks good to me.
      
      I suspect that these races are the root cause of some GPFs that I
      episodically hit.  Previously I did not have any explanation for them.
      
        BUG: unable to handle kernel NULL pointer dereference at 00000000000000c8
        IP: qlist_free_all+0x2e/0xc0 mm/kasan/quarantine.c:155
        PGD 6aeea067
        PUD 60ed7067
        PMD 0
        Oops: 0000 [#1] SMP KASAN
        Dumping ftrace buffer:
           (ftrace buffer empty)
        Modules linked in:
        CPU: 0 PID: 13667 Comm: syz-executor2 Not tainted 4.10.0+ #60
        Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
        task: ffff88005f948040 task.stack: ffff880069818000
        RIP: 0010:qlist_free_all+0x2e/0xc0 mm/kasan/quarantine.c:155
        RSP: 0018:ffff88006981f298 EFLAGS: 00010246
        RAX: ffffea0000ffff00 RBX: 0000000000000000 RCX: ffffea0000ffff1f
        RDX: 0000000000000000 RSI: ffff88003fffc3e0 RDI: 0000000000000000
        RBP: ffff88006981f2c0 R08: ffff88002fed7bd8 R09: 00000001001f000d
        R10: 00000000001f000d R11: ffff88006981f000 R12: ffff88003fffc3e0
        R13: ffff88006981f2d0 R14: ffffffff81877fae R15: 0000000080000000
        FS:  00007fb911a2d700(0000) GS:ffff88003ec00000(0000) knlGS:0000000000000000
        CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
        CR2: 00000000000000c8 CR3: 0000000060ed6000 CR4: 00000000000006f0
        Call Trace:
         quarantine_reduce+0x10e/0x120 mm/kasan/quarantine.c:239
         kasan_kmalloc+0xca/0xe0 mm/kasan/kasan.c:590
         kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:544
         slab_post_alloc_hook mm/slab.h:456 [inline]
         slab_alloc_node mm/slub.c:2718 [inline]
         kmem_cache_alloc_node+0x1d3/0x280 mm/slub.c:2754
         __alloc_skb+0x10f/0x770 net/core/skbuff.c:219
         alloc_skb include/linux/skbuff.h:932 [inline]
         _sctp_make_chunk+0x3b/0x260 net/sctp/sm_make_chunk.c:1388
         sctp_make_data net/sctp/sm_make_chunk.c:1420 [inline]
         sctp_make_datafrag_empty+0x208/0x360 net/sctp/sm_make_chunk.c:746
         sctp_datamsg_from_user+0x7e8/0x11d0 net/sctp/chunk.c:266
         sctp_sendmsg+0x2611/0x3970 net/sctp/socket.c:1962
         inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:761
         sock_sendmsg_nosec net/socket.c:633 [inline]
         sock_sendmsg+0xca/0x110 net/socket.c:643
         SYSC_sendto+0x660/0x810 net/socket.c:1685
         SyS_sendto+0x40/0x50 net/socket.c:1653
      
      I am not sure about backporting.  The bug is quite hard to trigger, I've
      seen it few times during our massive continuous testing (however, it
      could be cause of some other episodic stray crashes as it leads to
      memory corruption...).  If it is triggered, the consequences are very
      bad -- almost definite bad memory corruption.  The fix is non trivial
      and has chances of introducing new bugs.  I am also not sure how
      actively people use KASAN on older releases.
      
      [dvyukov@google.com: - sorted includes[
        Link: http://lkml.kernel.org/r/20170309094028.51088-1-dvyukov@google.com
      Link: http://lkml.kernel.org/r/20170308151532.5070-1-dvyukov@google.comSigned-off-by: 's avatarDmitry Vyukov <dvyukov@google.com>
      Acked-by: 's avatarAndrey Ryabinin <aryabinin@virtuozzo.com>
      Cc: Greg Thelen <gthelen@google.com>
      Signed-off-by: 's avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
      ce5bec54
    • Dmitry Vyukov's avatar
      kasan: resched in quarantine_remove_cache() · 68fd814a
      Dmitry Vyukov authored
      We see reported stalls/lockups in quarantine_remove_cache() on machines
      with large amounts of RAM.  quarantine_remove_cache() needs to scan
      whole quarantine in order to take out all objects belonging to the
      cache.  Quarantine is currently 1/32-th of RAM, e.g.  on a machine with
      256GB of memory that will be 8GB.  Moreover quarantine scanning is a
      walk over uncached linked list, which is slow.
      
      Add cond_resched() after scanning of each non-empty batch of objects.
      Batches are specifically kept of reasonable size for quarantine_put().
      On a machine with 256GB of RAM we should have ~512 non-empty batches,
      each with 16MB of objects.
      
      Link: http://lkml.kernel.org/r/20170308154239.25440-1-dvyukov@google.comSigned-off-by: 's avatarDmitry Vyukov <dvyukov@google.com>
      Acked-by: 's avatarAndrey Ryabinin <aryabinin@virtuozzo.com>
      Cc: Greg Thelen <gthelen@google.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: 's avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
      68fd814a
  15. 09 Mar, 2017 1 commit
  16. 02 Mar, 2017 2 commits
    • Ingo Molnar's avatar
      sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> · 68db0cf1
      Ingo Molnar authored
      We are going to split <linux/sched/task_stack.h> out of <linux/sched.h>, which
      will have to be picked up from other headers and a couple of .c files.
      
      Create a trivial placeholder <linux/sched/task_stack.h> file that just
      maps to <linux/sched.h> to make this patch obviously correct and
      bisectable.
      
      Include the new header in the files that are going to need it.
      Acked-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: linux-kernel@vger.kernel.org
      Signed-off-by: 's avatarIngo Molnar <mingo@kernel.org>
      68db0cf1
    • Ingo Molnar's avatar
      kasan, sched/headers: Uninline kasan_enable/disable_current() · af8601ad
      Ingo Molnar authored
      <linux/kasan.h> is a low level header that is included early
      in affected kernel headers. But it includes <linux/sched.h>
      which complicates the cleanup of sched.h dependencies.
      
      But kasan.h has almost no need for sched.h: its only use of
      scheduler functionality is in two inline functions which are
      not used very frequently - so uninline kasan_enable_current()
      and kasan_disable_current().
      
      Also add a <linux/sched.h> dependency to a .c file that depended
      on kasan.h including it.
      
      This paves the way to remove the <linux/sched.h> include from kasan.h.
      Acked-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: linux-kernel@vger.kernel.org
      Signed-off-by: 's avatarIngo Molnar <mingo@kernel.org>
      af8601ad
  17. 25 Feb, 2017 1 commit
    • Greg Thelen's avatar
      kasan: drain quarantine of memcg slab objects · f9fa1d91
      Greg Thelen authored
      Per memcg slab accounting and kasan have a problem with kmem_cache
      destruction.
       - kmem_cache_create() allocates a kmem_cache, which is used for
         allocations from processes running in root (top) memcg.
       - Processes running in non root memcg and allocating with either
         __GFP_ACCOUNT or from a SLAB_ACCOUNT cache use a per memcg
         kmem_cache.
       - Kasan catches use-after-free by having kfree() and kmem_cache_free()
         defer freeing of objects. Objects are placed in a quarantine.
       - kmem_cache_destroy() destroys root and non root kmem_caches. It takes
         care to drain the quarantine of objects from the root memcg's
         kmem_cache, but ignores objects associated with non root memcg. This
         causes leaks because quarantined per memcg objects refer to per memcg
         kmem cache being destroyed.
      
      To see the problem:
      
       1) create a slab cache with kmem_cache_create(,,,SLAB_ACCOUNT,)
       2) from non root memcg, allocate and free a few objects from cache
       3) dispose of the cache with kmem_cache_destroy() kmem_cache_destroy()
          will trigger a "Slab cache still has objects" warning indicating
          that the per memcg kmem_cache structure was leaked.
      
      Fix the leak by draining kasan quarantined objects allocated from non
      root memcg.
      
      Racing memcg deletion is tricky, but handled.  kmem_cache_destroy() =>
      shutdown_memcg_caches() => __shutdown_memcg_cache() => shutdown_cache()
      flushes per memcg quarantined objects, even if that memcg has been
      rmdir'd and gone through memcg_deactivate_kmem_caches().
      
      This leak only affects destroyed SLAB_ACCOUNT kmem caches when kasan is
      enabled.  So I don't think it's worth patching stable kernels.
      
      Link: http://lkml.kernel.org/r/1482257462-36948-1-git-send-email-gthelen@google.comSigned-off-by: 's avatarGreg Thelen <gthelen@google.com>
      Reviewed-by: 's avatarVladimir Davydov <vdavydov.dev@gmail.com>
      Acked-by: 's avatarAndrey Ryabinin <aryabinin@virtuozzo.com>
      Cc: Alexander Potapenko <glider@google.com>
      Cc: Dmitry Vyukov <dvyukov@google.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: 's avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
      f9fa1d91
  18. 03 Feb, 2017 1 commit