<feed xmlns='http://www.w3.org/2005/Atom'>
<title>user/sven/linux.git, branch v5.13.1</title>
<subtitle>Linux Kernel
</subtitle>
<id>https://git.stealer.net/cgit.cgi/user/sven/linux.git/atom?h=v5.13.1</id>
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<updated>2021-07-07T12:24:58Z</updated>
<entry>
<title>Linux 5.13.1</title>
<updated>2021-07-07T12:24:58Z</updated>
<author>
<name>Sasha Levin</name>
<email>sashal@kernel.org</email>
</author>
<published>2021-07-07T12:24:58Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=aaa1f5834d71fe7b687a0c41834bd8d4cc733d90'/>
<id>urn:sha1:aaa1f5834d71fe7b687a0c41834bd8d4cc733d90</id>
<content type='text'>
Tested-by: Fox Chen &lt;foxhlchen@gmail.com&gt;
Tested-by: Guenter Roeck &lt;linux@roeck-us.net&gt;
Tested-by: Linux Kernel Functional Testing &lt;lkft@linaro.org&gt;
Tested-by: Shuah Khan &lt;skhan@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>mm/page_alloc: correct return value of populated elements if bulk array is populated</title>
<updated>2021-07-07T12:22:32Z</updated>
<author>
<name>Mel Gorman</name>
<email>mgorman@techsingularity.net</email>
</author>
<published>2021-06-29T02:33:29Z</published>
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<id>urn:sha1:7f6cbd0b3e1e8c96e1c8773bb3978825dec5d00a</id>
<content type='text'>
commit ff4b2b4014cbffb3d32b22629252f4dc8616b0fe upstream.

Dave Jones reported the following

	This made it into 5.13 final, and completely breaks NFSD for me
	(Serving tcp v3 mounts).  Existing mounts on clients hang, as do
	new mounts from new clients.  Rebooting the server back to rc7
	everything recovers.

The commit b3b64ebd3822 ("mm/page_alloc: do bulk array bounds check after
checking populated elements") returns the wrong value if the array is
already populated which is interpreted as an allocation failure.  Dave
reported this fixes his problem and it also passed a test running dbench
over NFS.

Link: https://lkml.kernel.org/r/20210628150219.GC3840@techsingularity.net
Fixes: b3b64ebd3822 ("mm/page_alloc: do bulk array bounds check after checking populated elements")
Signed-off-by: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Reported-by: Dave Jones &lt;davej@codemonkey.org.uk&gt;
Tested-by: Dave Jones &lt;davej@codemonkey.org.uk&gt;
Cc: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Cc: Jesper Dangaard Brouer &lt;brouer@redhat.com&gt;
Cc: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: &lt;stable@vger.kernel.org&gt; [5.13+]
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>Revert "KVM: x86/mmu: Drop kvm_mmu_extended_role.cr4_la57 hack"</title>
<updated>2021-07-07T12:22:32Z</updated>
<author>
<name>Sean Christopherson</name>
<email>seanjc@google.com</email>
</author>
<published>2021-06-22T17:56:50Z</published>
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<id>urn:sha1:5863699d23914b2526b519adc17cb02fb76c165f</id>
<content type='text'>
commit f71a53d1180d5ecc346f0c6a23191d837fe2871b upstream.

Restore CR4.LA57 to the mmu_role to fix an amusing edge case with nested
virtualization.  When KVM (L0) is using TDP, CR4.LA57 is not reflected in
mmu_role.base.level because that tracks the shadow root level, i.e. TDP
level.  Normally, this is not an issue because LA57 can't be toggled
while long mode is active, i.e. the guest has to first disable paging,
then toggle LA57, then re-enable paging, thus ensuring an MMU
reinitialization.

But if L1 is crafty, it can load a new CR4 on VM-Exit and toggle LA57
without having to bounce through an unpaged section.  L1 can also load a
new CR3 on exit, i.e. it doesn't even need to play crazy paging games, a
single entry PML5 is sufficient.  Such shenanigans are only problematic
if L0 and L1 use TDP, otherwise L1 and L2 share an MMU that gets
reinitialized on nested VM-Enter/VM-Exit due to mmu_role.base.guest_mode.

Note, in the L2 case with nested TDP, even though L1 can switch between
L2s with different LA57 settings, thus bypassing the paging requirement,
in that case KVM's nested_mmu will track LA57 in base.level.

This reverts commit 8053f924cad30bf9f9a24e02b6c8ddfabf5202ea.

Fixes: 8053f924cad3 ("KVM: x86/mmu: Drop kvm_mmu_extended_role.cr4_la57 hack")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson &lt;seanjc@google.com&gt;
Message-Id: &lt;20210622175739.3610207-6-seanjc@google.com&gt;
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>Linux 5.13</title>
<updated>2021-06-27T22:21:11Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-06-27T22:21:11Z</published>
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<id>urn:sha1:62fb9874f5da54fdb243003b386128037319b219</id>
<content type='text'>
</content>
</entry>
<entry>
<title>Revert "signal: Allow tasks to cache one sigqueue struct"</title>
<updated>2021-06-27T20:32:54Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-06-27T20:32:54Z</published>
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<id>urn:sha1:b4b27b9eed8ebdbf9f3046197d29d733c8c944f3</id>
<content type='text'>
This reverts commits 4bad58ebc8bc4f20d89cff95417c9b4674769709 (and
399f8dd9a866e107639eabd3c1979cd526ca3a98, which tried to fix it).

I do not believe these are correct, and I'm about to release 5.13, so am
reverting them out of an abundance of caution.

The locking is odd, and appears broken.

On the allocation side (in __sigqueue_alloc()), the locking is somewhat
straightforward: it depends on sighand-&gt;siglock.  Since one caller
doesn't hold that lock, it further then tests 'sigqueue_flags' to avoid
the case with no locks held.

On the freeing side (in sigqueue_cache_or_free()), there is no locking
at all, and the logic instead depends on 'current' being a single
thread, and not able to race with itself.

To make things more exciting, there's also the data race between freeing
a signal and allocating one, which is handled by using WRITE_ONCE() and
READ_ONCE(), and being mutually exclusive wrt the initial state (ie
freeing will only free if the old state was NULL, while allocating will
obviously only use the value if it was non-NULL, so only one or the
other will actually act on the value).

However, while the free-&gt;alloc paths do seem mutually exclusive thanks
to just the data value dependency, it's not clear what the memory
ordering constraints are on it.  Could writes from the previous
allocation possibly be delayed and seen by the new allocation later,
causing logical inconsistencies?

So it's all very exciting and unusual.

And in particular, it seems that the freeing side is incorrect in
depending on "current" being single-threaded.  Yes, 'current' is a
single thread, but in the presense of asynchronous events even a single
thread can have data races.

And such asynchronous events can and do happen, with interrupts causing
signals to be flushed and thus free'd (for example - sending a
SIGCONT/SIGSTOP can happen from interrupt context, and can flush
previously queued process control signals).

So regardless of all the other questions about the memory ordering and
locking for this new cached allocation, the sigqueue_cache_or_free()
assumptions seem to be fundamentally incorrect.

It may be that people will show me the errors of my ways, and tell me
why this is all safe after all.  We can reinstate it if so.  But my
current belief is that the WRITE_ONCE() that sets the cached entry needs
to be a smp_store_release(), and the READ_ONCE() that finds a cached
entry needs to be a smp_load_acquire() to handle memory ordering
correctly.

And the sequence in sigqueue_cache_or_free() would need to either use a
lock or at least be interrupt-safe some way (perhaps by using something
like the percpu 'cmpxchg': it doesn't need to be SMP-safe, but like the
percpu operations it needs to be interrupt-safe).

Fixes: 399f8dd9a866 ("signal: Prevent sigqueue caching after task got released")
Fixes: 4bad58ebc8bc ("signal: Allow tasks to cache one sigqueue struct")
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Oleg Nesterov &lt;oleg@redhat.com&gt;
Cc: Christian Brauner &lt;christian.brauner@ubuntu.com&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>Merge tag 's390-5.13-5' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux</title>
<updated>2021-06-26T16:50:10Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-06-26T16:50:10Z</published>
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<id>urn:sha1:625acffd7ae2c52898d249e6c5c39f348db0d8df</id>
<content type='text'>
Pull s390 fixes from Vasily Gorbik:

 - Fix a couple of late pt_regs flags handling findings of conversion to
   generic entry.

 - Fix potential register clobbering in stack switch helper.

 - Fix thread/group masks for offline cpus.

 - Fix cleanup of mdev resources when remove callback is invoked in
   vfio-ap code.

* tag 's390-5.13-5' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/stack: fix possible register corruption with stack switch helper
  s390/topology: clear thread/group maps for offline cpus
  s390/vfio-ap: clean up mdev resources when remove callback invoked
  s390: clear pt_regs::flags on irq entry
  s390: fix system call restart with multiple signals
</content>
</entry>
<entry>
<title>Merge tag 'pinctrl-v5.13-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl</title>
<updated>2021-06-26T02:06:24Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-06-26T02:06:24Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=b7050b242430f3170e0b57f5f55136e44cb8dc66'/>
<id>urn:sha1:b7050b242430f3170e0b57f5f55136e44cb8dc66</id>
<content type='text'>
Pull pin control fixes from Linus Walleij:
 "Two last-minute fixes:

   - Put an fwnode in the errorpath in the SGPIO driver

   - Fix the number of GPIO lines per bank in the STM32 driver"

* tag 'pinctrl-v5.13-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl:
  pinctrl: stm32: fix the reported number of GPIO lines per bank
  pinctrl: microchip-sgpio: Put fwnode in error case during -&gt;probe()
</content>
</entry>
<entry>
<title>Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi</title>
<updated>2021-06-25T22:59:14Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-06-25T22:59:14Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=e2f527b58e8115dae15ae344215accdd7a42e5ba'/>
<id>urn:sha1:e2f527b58e8115dae15ae344215accdd7a42e5ba</id>
<content type='text'>
Pull SCSI fixes from James Bottomley:
 "Two small fixes, both in upper layer drivers (scsi disk and cdrom).

  The sd one is fixing a commit changing revalidation that came from the
  block tree a while ago (5.10) and the sr one adds handling of a
  condition we didn't previously handle for manually removed media"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: sd: Call sd_revalidate_disk() for ioctl(BLKRRPART)
  scsi: sr: Return appropriate error code when disk is ejected
</content>
</entry>
<entry>
<title>Merge branch 'akpm' (patches from Andrew)</title>
<updated>2021-06-25T18:05:03Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-06-25T18:05:03Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=7ce32ac6fb2fc73584b567c73ae0c47528954ec6'/>
<id>urn:sha1:7ce32ac6fb2fc73584b567c73ae0c47528954ec6</id>
<content type='text'>
Merge misc fixes from Andrew Morton:
 "24 patches, based on 4a09d388f2ab382f217a764e6a152b3f614246f6.

  Subsystems affected by this patch series: mm (thp, vmalloc, hugetlb,
  memory-failure, and pagealloc), nilfs2, kthread, MAINTAINERS, and
  mailmap"

* emailed patches from Andrew Morton &lt;akpm@linux-foundation.org&gt;: (24 commits)
  mailmap: add Marek's other e-mail address and identity without diacritics
  MAINTAINERS: fix Marek's identity again
  mm/page_alloc: do bulk array bounds check after checking populated elements
  mm/page_alloc: __alloc_pages_bulk(): do bounds check before accessing array
  mm/hwpoison: do not lock page again when me_huge_page() successfully recovers
  mm,hwpoison: return -EHWPOISON to denote that the page has already been poisoned
  mm/memory-failure: use a mutex to avoid memory_failure() races
  mm, futex: fix shared futex pgoff on shmem huge page
  kthread: prevent deadlock when kthread_mod_delayed_work() races with kthread_cancel_delayed_work_sync()
  kthread_worker: split code for canceling the delayed work timer
  mm/vmalloc: unbreak kasan vmalloc support
  KVM: s390: prepare for hugepage vmalloc
  mm/vmalloc: add vmalloc_no_huge
  nilfs2: fix memory leak in nilfs_sysfs_delete_device_group
  mm/thp: another PVMW_SYNC fix in page_vma_mapped_walk()
  mm/thp: fix page_vma_mapped_walk() if THP mapped by ptes
  mm: page_vma_mapped_walk(): get vma_address_end() earlier
  mm: page_vma_mapped_walk(): use goto instead of while (1)
  mm: page_vma_mapped_walk(): add a level of indentation
  mm: page_vma_mapped_walk(): crossing page table boundary
  ...
</content>
</entry>
<entry>
<title>userfaultfd: uapi: fix UFFDIO_CONTINUE ioctl request definition</title>
<updated>2021-06-25T17:53:26Z</updated>
<author>
<name>Gleb Fotengauer-Malinovskiy</name>
<email>glebfm@altlinux.org</email>
</author>
<published>2021-06-25T17:36:55Z</published>
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<id>urn:sha1:808e9df477757955a9644ca323010339be0c40ee</id>
<content type='text'>
This ioctl request reads from uffdio_continue structure written by
userspace which justifies _IOC_WRITE flag.  It also writes back to that
structure which justifies _IOC_READ flag.

See NOTEs in include/uapi/asm-generic/ioctl.h for more information.

Fixes: f619147104c8 ("userfaultfd: add UFFDIO_CONTINUE ioctl")
Signed-off-by: Gleb Fotengauer-Malinovskiy &lt;glebfm@altlinux.org&gt;
Acked-by: Peter Xu &lt;peterx@redhat.com&gt;
Reviewed-by: Axel Rasmussen &lt;axelrasmussen@google.com&gt;
Reviewed-by: Dmitry V. Levin &lt;ldv@altlinux.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
</feed>
