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  1. 30 Jul, 2021 4 commits
    • Johannes Weiner's avatar
      mm: memcontrol: fix blocking rstat function called from atomic cgroup1 thresholding code · 30def935
      Johannes Weiner authored 
      Dan Carpenter reports:

    The patch 2d146aa3: "mm: memcontrol: switch to rstat" from Apr
    29, 2021, leads to the following static checker warning:

	    kernel/cgroup/rstat.c:200 cgroup_rstat_flush()
	    warn: sleeping in atomic context

    mm/memcontrol.c
      3572  static unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
      3573  {
      3574          unsigned long val;
      3575
      3576          if (mem_cgroup_is_root(memcg)) {
      3577                  cgroup_rstat_flush(memcg->css.cgroup);
			    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

    This is from static analysis and potentially a false positive.  The
    problem is that mem_cgroup_usage() is called from __mem_cgroup_threshold()
    which holds an rcu_read_lock().  And the cgroup_rstat_flush() function
    can sleep.

      3578                  val = memcg_page_state(memcg, NR_FILE_PAGES) +
      3579                          memcg_page_state(memcg, NR_ANON_MAPPED);
      3580                  if (swap)
      3581                          val += memcg_page_state(memcg, MEMCG_SWAP);
      3582          } else {
      3583                  if (!swap)
      3584                          val = page_counter_read(&memcg->memory);
      3585                  else
      3586                          val = page_counter_read(&memcg->memsw);
      3587          }
      3588          return val;
      3589  }

__mem_cgroup_threshold() indeed holds the rcu lock.  In addition, the
thresholding code is invoked during stat changes, and those contexts
have irqs disabled as well.  If the lock breaking occurs inside the
flush function, it will result in a sleep from an atomic context.

Use the irqsafe flushing variant in mem_cgroup_usage() to fix this.

Link: https://lkml.kernel.org/r/20210726150019.251820-1-hannes@cmpxchg.org
Fixes: 2d146aa3 ("mm: memcontrol: switch to rstat")
Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Reported-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Acked-by: default avatarChris Down <chris@chrisdown.name>
Reviewed-by: default avatarRik van Riel <riel@surriel.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Reviewed-by: default avatarShakeel Butt <shakeelb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      30def935
    • Junxiao Bi's avatar
      ocfs2: issue zeroout to EOF blocks · 9449ad33
      Junxiao Bi authored 
      For punch holes in EOF blocks, fallocate used buffer write to zero the
EOF blocks in last cluster.  But since ->writepage will ignore EOF
pages, those zeros will not be flushed.

This "looks" ok as commit 6bba4471 ("ocfs2: fix data corruption by
fallocate") will zero the EOF blocks when extend the file size, but it
isn't.  The problem happened on those EOF pages, before writeback, those
pages had DIRTY flag set and all buffer_head in them also had DIRTY flag
set, when writeback run by write_cache_pages(), DIRTY flag on the page
was cleared, but DIRTY flag on the buffer_head not.

When next write happened to those EOF pages, since buffer_head already
had DIRTY flag set, it would not mark page DIRTY again.  That made
writeback ignore them forever.  That will cause data corruption.  Even
directio write can't work because it will fail when trying to drop pages
caches before direct io, as it found the buffer_head for those pages
still had DIRTY flag set, then it will fall back to buffer io mode.

To make a summary of the issue, as writeback ingores EOF pages, once any
EOF page is generated, any write to it will only go to the page cache,
it will never be flushed to disk even file size extends and that page is
not EOF page any more.  The fix is to avoid zero EOF blocks with buffer
write.

The following code snippet from qemu-img could trigger the corruption.

  656   open("6b3711ae-3306-4bdd-823c-cf1c0060a095.conv.2", O_RDWR|O_DIRECT|O_CLOEXEC) = 11
  ...
  660   fallocate(11, FALLOC_FL_KEEP_SIZE|FALLOC_FL_PUNCH_HOLE, 2275868672, 327680 <unfinished ...>
  660   fallocate(11, 0, 2275868672, 327680) = 0
  658   pwrite64(11, "

Link: https://lkml.kernel.org/r/20210722054923.24389-2-junxiao.bi@oracle.comSigned-off-by: default avatarJunxiao Bi <junxiao.bi@oracle.com>
Reviewed-by: default avatarJoseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9449ad33
    • Junxiao Bi's avatar
      ocfs2: fix zero out valid data · f267aeb6
      Junxiao Bi authored 
      If append-dio feature is enabled, direct-io write and fallocate could
run in parallel to extend file size, fallocate used "orig_isize" to
record i_size before taking "ip_alloc_sem", when
ocfs2_zeroout_partial_cluster() zeroout EOF blocks, i_size maybe already
extended by ocfs2_dio_end_io_write(), that will cause valid data zeroed
out.

Link: https://lkml.kernel.org/r/20210722054923.24389-1-junxiao.bi@oracle.com
Fixes: 6bba4471 ("ocfs2: fix data corruption by fallocate")
Signed-off-by: default avatarJunxiao Bi <junxiao.bi@oracle.com>
Reviewed-by: default avatarJoseph Qi <joseph.qi@linux.alibaba.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Jun Piao <piaojun@huawei.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f267aeb6
    • Matteo Croce's avatar
      lib/test_string.c: move string selftest in the Runtime Testing menu · b2ff70a0
      Matteo Croce authored 
      STRING_SELFTEST is presented in the "Library routines" menu.  Move it in
Kernel hacking > Kernel Testing and Coverage > Runtime Testing together
with other similar tests found in lib/

	--- Runtime Testing
	<*>   Test functions located in the hexdump module at runtime
	<*>   Test string functions (NEW)
	<*>   Test functions located in the string_helpers module at runtime
	<*>   Test strscpy*() family of functions at runtime
	<*>   Test kstrto*() family of functions at runtime
	<*>   Test printf() family of functions at runtime
	<*>   Test scanf() family of functions at runtime

Link: https://lkml.kernel.org/r/20210719185158.190371-1-mcroce@linux.microsoft.comSigned-off-by: default avatarMatteo Croce <mcroce@microsoft.com>
Cc: Peter Rosin <peda@axentia.se>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
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>
      b2ff70a0
  3. 29 Jul, 2021 2 commits
    • Linus Torvalds's avatar
      Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm · 7e96bf47
      Linus Torvalds authored 
      Pull kvm fixes from Paolo Bonzini:
 "ARM:

   - Fix MTE shared page detection

   - Enable selftest's use of PMU registers when asked to

  s390:

   - restore 5.13 debugfs names

  x86:

   - fix sizes for vcpu-id indexed arrays

   - fixes for AMD virtualized LAPIC (AVIC)

   - other small bugfixes

  Generic:

   - access tracking performance test

   - dirty_log_perf_test command line parsing fix

   - Fix selftest use of obsolete pthread_yield() in favour of
     sched_yield()

   - use cpu_relax when halt polling

   - fixed missing KVM_CLEAR_DIRTY_LOG compat ioctl"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: add missing compat KVM_CLEAR_DIRTY_LOG
  KVM: use cpu_relax when halt polling
  KVM: SVM: use vmcb01 in svm_refresh_apicv_exec_ctrl
  KVM: SVM: tweak warning about enabled AVIC on nested entry
  KVM: SVM: svm_set_vintr don't warn if AVIC is active but is about to be deactivated
  KVM: s390: restore old debugfs names
  KVM: SVM: delay svm_vcpu_init_msrpm after svm->vmcb is initialized
  KVM: selftests: Introduce access_tracking_perf_test
  KVM: selftests: Fix missing break in dirty_log_perf_test arg parsing
  x86/kvm: fix vcpu-id indexed array sizes
  KVM: x86: Check the right feature bit for MSR_KVM_ASYNC_PF_ACK access
  docs: virt: kvm: api.rst: replace some characters
  KVM: Documentation: Fix KVM_CAP_ENFORCE_PV_FEATURE_CPUID name
  KVM: nSVM: Swap the parameter order for svm_copy_vmrun_state()/svm_copy_vmloadsave_state()
  KVM: nSVM: Rename nested_svm_vmloadsave() to svm_copy_vmloadsave_state()
  KVM: arm64: selftests: get-reg-list: actually enable pmu regs in pmu sublist
  KVM: selftests: change pthread_yield to sched_yield
  KVM: arm64: Fix detection of shared VMAs on guest fault
      7e96bf47
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu · 2b99c470
      Linus Torvalds authored 
      Pull m68knommu fix from Greg Ungerer:
 "A single compile time fix"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu:
  m68k/coldfire: change pll var. to clk_pll
      2b99c470
  5. 28 Jul, 2021 6 commits
  7. 27 Jul, 2021 13 commits
    • Linus Torvalds's avatar
      Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma · 7d549995
      Linus Torvalds authored 
      Pull rdma fixes from Jason Gunthorpe:
 "Nothing very exciting here, mainly just a bunch of irdma fixes. irdma
  is a new driver this cycle so it to be expected.

   - Many more irdma fixups from bots/etc

   - bnxt_re regression in their counters from a FW upgrade

   - User triggerable memory leak in rxe"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
  RDMA/irdma: Change returned type of irdma_setup_virt_qp to void
  RDMA/irdma: Change the returned type of irdma_set_hw_rsrc to void
  RDMA/irdma: change the returned type of irdma_sc_repost_aeq_entries to void
  RDMA/irdma: Check vsi pointer before using it
  RDMA/rxe: Fix memory leak in error path code
  RDMA/irdma: Change the returned type to void
  RDMA/irdma: Make spdxcheck.py happy
  RDMA/irdma: Fix unused variable total_size warning
  RDMA/bnxt_re: Fix stats counters
      7d549995
    • Linus Torvalds's avatar
      Merge branch 'for-5.14-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup · 51bbe7eb
      Linus Torvalds authored 
      Pull cgroup fix from Tejun Heo:
 "Fix leak of filesystem context root which is triggered by LTP.

  Not too likely to be a problem in non-testing environments"

* 'for-5.14-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup1: fix leaked context root causing sporadic NULL deref in LTP
      51bbe7eb
    • Paolo Bonzini's avatar
      KVM: add missing compat KVM_CLEAR_DIRTY_LOG · 8750f9bb
      Paolo Bonzini authored 
      The arguments to the KVM_CLEAR_DIRTY_LOG ioctl include a pointer,
therefore it needs a compat ioctl implementation.  Otherwise,
32-bit userspace fails to invoke it on 64-bit kernels; for x86
it might work fine by chance if the padding is zero, but not
on big-endian architectures.

Reported-by: Thomas Sattler
Cc: stable@vger.kernel.org
Fixes: 2a31b9db ("kvm: introduce manual dirty log reprotect")
Reviewed-by: default avatarPeter Xu <peterx@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      8750f9bb
    • Li RongQing's avatar
      KVM: use cpu_relax when halt polling · 74775654
      Li RongQing authored 
      SMT siblings share caches and other hardware, and busy halt polling
will degrade its sibling performance if its sibling is working

Sean Christopherson suggested as below:

"Rather than disallowing halt-polling entirely, on x86 it should be
sufficient to simply have the hardware thread yield to its sibling(s)
via PAUSE.  It probably won't get back all performance, but I would
expect it to be close.
This compiles on all KVM architectures, and AFAICT the intended usage
of cpu_relax() is identical for all architectures."
Suggested-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarLi RongQing <lirongqing@baidu.com>
Message-Id: <20210727111247.55510-1-lirongqing@baidu.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      74775654
    • Maxim Levitsky's avatar
      KVM: SVM: use vmcb01 in svm_refresh_apicv_exec_ctrl · 5868b822
      Maxim Levitsky authored 
      Currently when SVM is enabled in guest CPUID, AVIC is inhibited as soon
as the guest CPUID is set.

AVIC happens to be fully disabled on all vCPUs by the time any guest
entry starts (if after migration the entry can be nested).

The reason is that currently we disable avic right away on vCPU from which
the kvm_request_apicv_update was called and for this case, it happens to be
called on all vCPUs (by svm_vcpu_after_set_cpuid).

After we stop doing this, AVIC will end up being disabled only when
KVM_REQ_APICV_UPDATE is processed which is after we done switching to the
nested guest.

Fix this by just using vmcb01 in svm_refresh_apicv_exec_ctrl for avic
(which is a right thing to do anyway).
Signed-off-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210713142023.106183-4-mlevitsk@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      5868b822
    • Maxim Levitsky's avatar
      KVM: SVM: tweak warning about enabled AVIC on nested entry · feea0136
      Maxim Levitsky authored 
      It is possible that AVIC was requested to be disabled but
not yet disabled, e.g if the nested entry is done right
after svm_vcpu_after_set_cpuid.
Signed-off-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210713142023.106183-3-mlevitsk@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      feea0136
    • Maxim Levitsky's avatar
      KVM: SVM: svm_set_vintr don't warn if AVIC is active but is about to be deactivated · f1577ab2
      Maxim Levitsky authored 
      It is possible for AVIC inhibit and AVIC active state to be mismatched.
Currently we disable AVIC right away on vCPU which started the AVIC inhibit
request thus this warning doesn't trigger but at least in theory,
if svm_set_vintr is called at the same time on multiple vCPUs,
the warning can happen.
Signed-off-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210713142023.106183-2-mlevitsk@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      f1577ab2
    • Christian Borntraeger's avatar
      KVM: s390: restore old debugfs names · bb000f64
      Christian Borntraeger authored 
      commit bc9e9e67 ("KVM: debugfs: Reuse binary stats descriptors")
did replace the old definitions with the binary ones. While doing that
it missed that some files are names different than the counters. This
is especially important for kvm_stat which does have special handling
for counters named instruction_*.

Fixes: commit bc9e9e67 ("KVM: debugfs: Reuse binary stats descriptors")
CC: Jing Zhang <jingzhangos@google.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Message-Id: <20210726150108.5603-1-borntraeger@de.ibm.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      bb000f64
    • Paolo Bonzini's avatar
      KVM: SVM: delay svm_vcpu_init_msrpm after svm->vmcb is initialized · 3fa5e8fd
      Paolo Bonzini authored 
      Right now, svm_hv_vmcb_dirty_nested_enlightenments has an incorrect
dereference of vmcb->control.reserved_sw before the vmcb is checked
for being non-NULL.  The compiler is usually sinking the dereference
after the check; instead of doing this ourselves in the source,
ensure that svm_hv_vmcb_dirty_nested_enlightenments is only called
with a non-NULL VMCB.
Reported-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Cc: Vineeth Pillai <viremana@linux.microsoft.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
[Untested for now due to issues with my AMD machine. - Paolo]
      3fa5e8fd
    • David Matlack's avatar
      KVM: selftests: Introduce access_tracking_perf_test · c33e05d9
      David Matlack authored 
      This test measures the performance effects of KVM's access tracking.
Access tracking is driven by the MMU notifiers test_young, clear_young,
and clear_flush_young. These notifiers do not have a direct userspace
API, however the clear_young notifier can be triggered by marking a
pages as idle in /sys/kernel/mm/page_idle/bitmap. This test leverages
that mechanism to enable access tracking on guest memory.

To measure performance this test runs a VM with a configurable number of
vCPUs that each touch every page in disjoint regions of memory.
Performance is measured in the time it takes all vCPUs to finish
touching their predefined region.

Example invocation:

  $ ./access_tracking_perf_test -v 8
  Testing guest mode: PA-bits:ANY, VA-bits:48,  4K pages
  guest physical test memory offset: 0xffdfffff000

  Populating memory             : 1.337752570s
  Writing to populated memory   : 0.010177640s
  Reading from populated memory : 0.009548239s
  Mark memory idle              : 23.973131748s
  Writing to idle memory        : 0.063584496s
  Mark memory idle              : 24.924652964s
  Reading from idle memory      : 0.062042814s

Breaking down the results:

 * "Populating memory": The time it takes for all vCPUs to perform the
   first write to every page in their region.

 * "Writing to populated memory" / "Reading from populated memory": The
   time it takes for all vCPUs to write and read to every page in their
   region after it has been populated. This serves as a control for the
   later results.

 * "Mark memory idle": The time it takes for every vCPU to mark every
   page in their region as idle through page_idle.

 * "Writing to idle memory" / "Reading from idle memory": The time it
   takes for all vCPUs to write and read to every page in their region
   after it has been marked idle.

This test should be portable across architectures but it is only enabled
for x86_64 since that's all I have tested.
Reviewed-by: default avatarBen Gardon <bgardon@google.com>
Signed-off-by: default avatarDavid Matlack <dmatlack@google.com>
Message-Id: <20210713220957.3493520-7-dmatlack@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      c33e05d9
    • David Matlack's avatar
      KVM: selftests: Fix missing break in dirty_log_perf_test arg parsing · 15b7b737
      David Matlack authored 
      There is a missing break statement which causes a fallthrough to the
next statement where optarg will be null and a segmentation fault will
be generated.

Fixes: 9e965bb7 ("KVM: selftests: Add backing src parameter to dirty_log_perf_test")
Reviewed-by: default avatarBen Gardon <bgardon@google.com>
Signed-off-by: default avatarDavid Matlack <dmatlack@google.com>
Message-Id: <20210713220957.3493520-6-dmatlack@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      15b7b737
    • Juergen Gross's avatar
      x86/kvm: fix vcpu-id indexed array sizes · 76b4f357
      Juergen Gross authored 
      KVM_MAX_VCPU_ID is the maximum vcpu-id of a guest, and not the number
of vcpu-ids. Fix array indexed by vcpu-id to have KVM_MAX_VCPU_ID+1
elements.

Note that this is currently no real problem, as KVM_MAX_VCPU_ID is
an odd number, resulting in always enough padding being available at
the end of those arrays.

Nevertheless this should be fixed in order to avoid rare problems in
case someone is using an even number for KVM_MAX_VCPU_ID.
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Message-Id: <20210701154105.23215-2-jgross@suse.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      76b4f357
    • Linus Torvalds's avatar
      Merge branch 'for-5.14-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq · 82d712f6
      Linus Torvalds authored 
      Pull workqueue fix from Tejun Heo:
 "Fix a use-after-free in allocation failure handling path"

* 'for-5.14-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: fix UAF in pwq_unbound_release_workfn()
      82d712f6
  9. 26 Jul, 2021 5 commits
  11. 25 Jul, 2021 10 commits
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