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  1. 03 Aug, 2019 6 commits
    • Mel Gorman's avatar
      mm: compaction: avoid 100% CPU usage during compaction when a task is killed · 670105a2
      Mel Gorman authored 
      "howaboutsynergy" reported via kernel buzilla number 204165 that
compact_zone_order was consuming 100% CPU during a stress test for
prolonged periods of time.  Specifically the following command, which
should exit in 10 seconds, was taking an excessive time to finish while
the CPU was pegged at 100%.

  stress -m 220 --vm-bytes 1000000000 --timeout 10

Tracing indicated a pattern as follows

          stress-3923  [007]   519.106208: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0
          stress-3923  [007]   519.106212: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0
          stress-3923  [007]   519.106216: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0
          stress-3923  [007]   519.106219: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0
          stress-3923  [007]   519.106223: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0
          stress-3923  [007]   519.106227: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0
          stress-3923  [007]   519.106231: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0
          stress-3923  [007]   519.106235: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0
          stress-3923  [007]   519.106238: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0
          stress-3923  [007]   519.106242: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0

Note that compaction is entered in rapid succession while scanning and
isolating nothing.  The problem is that when a task that is compacting
receives a fatal signal, it retries indefinitely instead of exiting
while making no progress as a fatal signal is pending.

It's not easy to trigger this condition although enabling zswap helps on
the basis that the timing is altered.  A very small window has to be hit
for the problem to occur (signal delivered while compacting and
isolating a PFN for migration that is not aligned to SWAP_CLUSTER_MAX).

This was reproduced locally -- 16G single socket system, 8G swap, 30%
zswap configured, vm-bytes 22000000000 using Colin Kings stress-ng
implementation from github running in a loop until the problem hits).
Tracing recorded the problem occurring almost 200K times in a short
window.  With this patch, the problem hit 4 times but the task existed
normally instead of consuming CPU.

This problem has existed for some time but it was made worse by commit
cf66f070 ("mm, compaction: do not consider a need to reschedule as
contention").  Before that commit, if the same condition was hit then
locks would be quickly contended and compaction would exit that way.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204165
Link: http://lkml.kernel.org/r/20190718085708.GE24383@techsingularity.net
Fixes: cf66f070 ("mm, compaction: do not consider a need to reschedule as contention")
Signed-off-by: default avatarMel Gorman <mgorman@techsingularity.net>
Reviewed-by: default avatarVlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>	[5.1+]
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      670105a2
    • Jan Kara's avatar
      mm: migrate: fix reference check race between __find_get_block() and migration · ebdf4de5
      Jan Kara authored 
      buffer_migrate_page_norefs() can race with bh users in the following
way:

CPU1                                    CPU2
buffer_migrate_page_norefs()
  buffer_migrate_lock_buffers()
  checks bh refs
  spin_unlock(&mapping->private_lock)
                                        __find_get_block()
                                          spin_lock(&mapping->private_lock)
                                          grab bh ref
                                          spin_unlock(&mapping->private_lock)
  move page                               do bh work

This can result in various issues like lost updates to buffers (i.e.
metadata corruption) or use after free issues for the old page.

This patch closes the race by holding mapping->private_lock while the
mapping is being moved to a new page.  Ordinarily, a reference can be
taken outside of the private_lock using the per-cpu BH LRU but the
references are checked and the LRU invalidated if necessary.  The
private_lock is held once the references are known so the buffer lookup
slow path will spin on the private_lock.  Between the page lock and
private_lock, it should be impossible for other references to be
acquired and updates to happen during the migration.

A user had reported data corruption issues on a distribution kernel with
a similar page migration implementation as mainline.  The data
corruption could not be reproduced with this patch applied.  A small
number of migration-intensive tests were run and no performance problems
were noted.

[mgorman@techsingularity.net: Changelog, removed tracing]
Link: http://lkml.kernel.org/r/20190718090238.GF24383@techsingularity.net
Fixes: 89cb0888 "mm: migrate: provide buffer_migrate_page_norefs()"
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarMel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>	[5.0+]
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ebdf4de5
    • Yang Shi's avatar
      mm: vmscan: check if mem cgroup is disabled or not before calling memcg slab shrinker · fa1e512f
      Yang Shi authored 
      Shakeel Butt reported premature oom on kernel with
"cgroup_disable=memory" since mem_cgroup_is_root() returns false even
though memcg is actually NULL.  The drop_caches is also broken.

It is because commit aeed1d32 ("mm/vmscan.c: generalize
shrink_slab() calls in shrink_node()") removed the !memcg check before
!mem_cgroup_is_root().  And, surprisingly root memcg is allocated even
though memory cgroup is disabled by kernel boot parameter.

Add mem_cgroup_disabled() check to make reclaimer work as expected.

Link: http://lkml.kernel.org/r/1563385526-20805-1-git-send-email-yang.shi@linux.alibaba.com
Fixes: aeed1d32 ("mm/vmscan.c: generalize shrink_slab() calls in shrink_node()")
Signed-off-by: default avatarYang Shi <yang.shi@linux.alibaba.com>
Reported-by: default avatarShakeel Butt <shakeelb@google.com>
Reviewed-by: default avatarShakeel Butt <shakeelb@google.com>
Reviewed-by: default avatarKirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Jan Hadrava <had@kam.mff.cuni.cz>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org>	[4.19+]
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      fa1e512f
    • YueHaibing's avatar
      ocfs2: remove set but not used variable 'last_hash' · 7bc36e3c
      YueHaibing authored 
      Fixes gcc '-Wunused-but-set-variable' warning:

  fs/ocfs2/xattr.c: In function ocfs2_xattr_bucket_find:
  fs/ocfs2/xattr.c:3828:6: warning: variable last_hash set but not used [-Wunused-but-set-variable]

It's never used and can be removed.

Link: http://lkml.kernel.org/r/20190716132110.34836-1-yuehaibing@huawei.comSigned-off-by: default avatarYueHaibing <yuehaibing@huawei.com>
Acked-by: default avatarJoseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7bc36e3c
    • Yang Shi's avatar
      Revert "kmemleak: allow to coexist with fault injection" · df9576de
      Yang Shi authored 
      When running ltp's oom test with kmemleak enabled, the below warning was
triggerred since kernel detects __GFP_NOFAIL & ~__GFP_DIRECT_RECLAIM is
passed in:

  WARNING: CPU: 105 PID: 2138 at mm/page_alloc.c:4608 __alloc_pages_nodemask+0x1c31/0x1d50
  Modules linked in: loop dax_pmem dax_pmem_core ip_tables x_tables xfs virtio_net net_failover virtio_blk failover ata_generic virtio_pci virtio_ring virtio libata
  CPU: 105 PID: 2138 Comm: oom01 Not tainted 5.2.0-next-20190710+ #7
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
  RIP: 0010:__alloc_pages_nodemask+0x1c31/0x1d50
  ...
   kmemleak_alloc+0x4e/0xb0
   kmem_cache_alloc+0x2a7/0x3e0
   mempool_alloc_slab+0x2d/0x40
   mempool_alloc+0x118/0x2b0
   bio_alloc_bioset+0x19d/0x350
   get_swap_bio+0x80/0x230
   __swap_writepage+0x5ff/0xb20

The mempool_alloc_slab() clears __GFP_DIRECT_RECLAIM, however kmemleak
has __GFP_NOFAIL set all the time due to d9570ee3 ("kmemleak:
allow to coexist with fault injection").  But, it doesn't make any sense
to have __GFP_NOFAIL and ~__GFP_DIRECT_RECLAIM specified at the same
time.

According to the discussion on the mailing list, the commit should be
reverted for short term solution.  Catalin Marinas would follow up with
a better solution for longer term.

The failure rate of kmemleak metadata allocation may increase in some
circumstances, but this should be expected side effect.

Link: http://lkml.kernel.org/r/1563299431-111710-1-git-send-email-yang.shi@linux.alibaba.com
Fixes: d9570ee3 ("kmemleak: allow to coexist with fault injection")
Signed-off-by: default avatarYang Shi <yang.shi@linux.alibaba.com>
Suggested-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      df9576de
    • Mauro Carvalho Chehab's avatar
      kernel/signal.c: fix a kernel-doc markup · 68d8681e
      Mauro Carvalho Chehab authored 
      The kernel-doc parser doesn't handle expressions with %foo*.  Instead,
when an asterisk should be part of a constant, it uses an alternative
notation: `foo*`.

Link: http://lkml.kernel.org/r/7f18c2e0b5e39e6b7eb55ddeb043b8b260b49f2d.1563361575.git.mchehab+samsung@kernel.orgSigned-off-by: default avatarMauro Carvalho Chehab <mchehab+samsung@kernel.org>
Cc: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      68d8681e
  3. 02 Aug, 2019 8 commits
    • Linus Torvalds's avatar
      Merge tag 'gfs2-v5.3-rc2.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2 · 97b00aff
      Linus Torvalds authored 
      Pull gfs2 fix from Andreas Gruenbacher:
 "Fix gfs2 cluster coherency bug"

* tag 'gfs2-v5.3-rc2.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
  gfs2: Inode dirtying fix
      97b00aff
    • Linus Torvalds's avatar
      Merge tag 'pm-5.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm · 755f1fed
      Linus Torvalds authored 
      Pull power management fix from Rafael Wysocki:
 "Fix recent regression affecting ACPI device power management"

* tag 'pm-5.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: PM: Fix regression in acpi_device_set_power()
      755f1fed
    • Linus Torvalds's avatar
      Merge tag 'sound-5.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound · 75cdf416
      Linus Torvalds authored 
      Pull sound fixes from Takashi Iwai:

 - A further fix for syzcaller issues with USB-audio, addressing NULL
   dereference that was introduced by the recent fix

 - Avoid a long delay at boot with HD-audio when i915 module was built
   but not installed, found on some Debian systems

 - A fix of small race window at PCM draining

* tag 'sound-5.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: usb-audio: Fix gpf in snd_usb_pipe_sanity_check
  ALSA: pcm: fix lost wakeup event scenarios in snd_pcm_drain
  ALSA: hda: Fix 1-minute detection delay when i915 module is not available
      75cdf416
    • Linus Torvalds's avatar
      Merge tag 'drm-fixes-2019-08-02' of git://anongit.freedesktop.org/drm/drm · f26dbb23
      Linus Torvalds authored 
      Pull drm fixes from Dave Airlie:
 "Thanks to Daniel for handling the email the last couple of weeks, flus
  and break-ins combined to derail me. Surprised nothing materialised
  today to take me out again.

  Just more amdgpu navi fixes, msm fixes and a single nouveau regression
  fix:

  amdgpu:
   - navi10 temperature and pstate fixes
   - vcn dynamic power management fix
   - CS ioctl error handling fix
   - debugfs info leak fix
   - amdkfd VegaM fix

  msm:
   - dma sync call fix
   - mdp5 dsi command mode fix
   - fall-through fixes
   - disabled GPU fix

  nouveau:
   - regression fix for displayport MST support"

* tag 'drm-fixes-2019-08-02' of git://anongit.freedesktop.org/drm/drm:
  drm/nouveau: Only release VCPI slots on mode changes
  drm: msm: Fix add_gpu_components
  drm/msm: Annotate intentional switch statement fall throughs
  drm/msm: add support for per-CRTC max_vblank_count on mdp5
  drm/msm: Use the correct dma_sync calls in msm_gem
  drm/amd/powerplay: correct UVD/VCE/VCN power status retrieval
  drm/amd/powerplay: correct Navi10 VCN powergate control (v2)
  drm/amd/powerplay: support VCN powergate status retrieval for SW SMU
  drm/amd/powerplay: support VCN powergate status retrieval on Raven
  drm/amd/powerplay: add new sensor type for VCN powergate status
  drm/amdgpu: fix a potential information leaking bug
  drm/amdgpu: fix error handling in amdgpu_cs_process_fence_dep
  drm/amd/powerplay: enable SW SMU reset functionality
  drm/amd/powerplay: fix null pointer dereference around dpm state relates
  drm/amdgpu/powerplay: use proper revision id for navi
  drm/amd/powerplay: fix temperature granularity error in smu11
  drm/amd/powerplay: add callback function of get_thermal_temperature_range
  drm/amdkfd: Fix byte align on VegaM
      f26dbb23
    • Linus Torvalds's avatar
      Merge tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux · 42d21900
      Linus Torvalds authored 
      Pull clk fixes from Stephen Boyd:
 "A few fixes for code that came in during the merge window or that
  started getting exercised differently this time around:

   - Select regmap MMIO kconfig in spreadtrum driver to avoid compile
     errors

   - Complete kerneldoc on devm_clk_bulk_get_optional()

   - Register an essential clk earlier on mediatek mt8183 SoCs so the
     clocksource driver can use it

   - Fix divisor math in the at91 driver

   - Plug a race in Renesas reset control logic"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  clk: renesas: cpg-mssr: Fix reset control race condition
  clk: sprd: Select REGMAP_MMIO to avoid compile errors
  clk: mediatek: mt8183: Register 13MHz clock earlier for clocksource
  clk: Add missing documentation of devm_clk_bulk_get_optional() argument
  clk: at91: generated: Truncate divisor to GENERATED_MAX_DIV + 1
      42d21900
    • Linus Torvalds's avatar
      Merge tag 'arm-swiotlb-5.3' of git://git.infradead.org/users/hch/dma-mapping · 234172f6
      Linus Torvalds authored 
      Pull arm swiotlb support from Christoph Hellwig:
 "This fixes a cascade of regressions that originally started with the
  addition of the ia64 port, but only got fatal once we removed most
  uses of block layer bounce buffering in Linux 4.18.

  The reason is that while the original i386/PAE code that was the first
  architecture that supported > 4GB of memory without an iommu decided
  to leave bounce buffering to the subsystems, which in those days just
  mean block and networking as no one else consumed arbitrary userspace
  memory.

  Later with ia64, x86_64 and other ports we assumed that either an
  iommu or something that fakes it up ("software IOTLB" in beautiful
  Intel speak) is present and that subsystems can rely on that for
  dealing with addressing limitations in devices. Except that the ARM
  LPAE scheme that added larger physical address to 32-bit ARM did not
  follow that scheme and thus only worked by chance and only for block
  and networking I/O directly to highmem.

  Long story, short fix - add swiotlb support to arm when build for LPAE
  platforms, which actuallys turns out to be pretty trivial with the
  modern dma-direct / swiotlb code to fix the Linux 4.18-ish regression"

* tag 'arm-swiotlb-5.3' of git://git.infradead.org/users/hch/dma-mapping:
  arm: use swiotlb for bounce buffering on LPAE configs
  dma-mapping: check pfn validity in dma_common_{mmap,get_sgtable}
      234172f6
    • Linus Torvalds's avatar
      Merge tag 'dma-mapping-5.3-3' of git://git.infradead.org/users/hch/dma-mapping · 35fca9f8
      Linus Torvalds authored 
      Pull dma-mapping regression fixes from Christoph Hellwig:
 "Two related regression fixes for changes from this merge window to fix
  alignment issues introduced in the CMA allocation rework (Nicolin
  Chen)"

* tag 'dma-mapping-5.3-3' of git://git.infradead.org/users/hch/dma-mapping:
  dma-contiguous: page-align the size in dma_free_contiguous()
  dma-contiguous: do not overwrite align in dma_alloc_contiguous()
      35fca9f8
    • Dave Airlie's avatar
      Merge tag 'msm-fixes-2019_08_01' of https://gitlab.freedesktop.org/drm/msm into drm-fixes · f8981e03
      Dave Airlie authored 
      - Fix the dma_sync calls applied last week (Rob)
- Fix mdp5 dsi command mode (Brian)
- Squash fall through warnings (Jordan)
- Don't add disabled gpu nodes to the of device list (Jeffrey)

Cc: Jeffrey Hugo <jeffrey.l.hugo@gmail.com>
Cc: Jordan Crouse <jcrouse@codeaurora.org>
Cc: Brian Masney <masneyb@onstation.org>
Cc: Rob Clark <robdclark@chromium.org>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>

# gpg: Signature made Fri 02 Aug 2019 05:54:27 AM AEST
# gpg:                using RSA key 96F70DFDA84A070A
# gpg: Can't check signature: public key not found
From: Sean Paul <sean@poorly.run>
Link: https://patchwork.freedesktop.org/patch/msgid/20190801200439.GV104440@art_vandelay
      f8981e03
  5. 01 Aug, 2019 8 commits
  7. 31 Jul, 2019 18 commits
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