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  1. 30 6月, 2021 1 次提交
    • M
      mm/page_alloc: fix memory map initialization for descending nodes · 122e093c
      由 Mike Rapoport 提交于 
      On systems with memory nodes sorted in descending order, for instance Dell
Precision WorkStation T5500, the struct pages for higher PFNs and
respectively lower nodes, could be overwritten by the initialization of
struct pages corresponding to the holes in the memory sections.

For example for the below memory layout

[    0.245624] Early memory node ranges
[    0.248496]   node   1: [mem 0x0000000000001000-0x0000000000090fff]
[    0.251376]   node   1: [mem 0x0000000000100000-0x00000000dbdf8fff]
[    0.254256]   node   1: [mem 0x0000000100000000-0x0000001423ffffff]
[    0.257144]   node   0: [mem 0x0000001424000000-0x0000002023ffffff]

the range 0x1424000000 - 0x1428000000 in the beginning of node 0 starts in
the middle of a section and will be considered as a hole during the
initialization of the last section in node 1.

The wrong initialization of the memory map causes panic on boot when
CONFIG_DEBUG_VM is enabled.

Reorder loop order of the memory map initialization so that the outer loop
will always iterate over populated memory regions in the ascending order
and the inner loop will select the zone corresponding to the PFN range.

This way initialization of the struct pages for the memory holes will be
always done for the ranges that are actually not populated.

[akpm@linux-foundation.org: coding style fixes]

Link: https://lkml.kernel.org/r/YNXlMqBbL+tBG7yq@kernel.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=213073
Link: https://lkml.kernel.org/r/20210624062305.10940-1-rppt@kernel.org
Fixes: 0740a50b ("mm/page_alloc.c: refactor initialization of struct page for holes in memory layout")
Signed-off-by: NMike Rapoport <rppt@linux.ibm.com>
Cc: Boris Petkov <bp@alien8.de>
Cc: Robert Shteynfeld <robert.shteynfeld@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      122e093c
  3. 28 6月, 2021 1 次提交
    • L
      Revert "signal: Allow tasks to cache one sigqueue struct" · b4b27b9e
      由 Linus Torvalds 提交于 
      This reverts commits 4bad58eb (and
399f8dd9, 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->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->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: 399f8dd9 ("signal: Prevent sigqueue caching after task got released")
Fixes: 4bad58eb ("signal: Allow tasks to cache one sigqueue struct")
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      b4b27b9e
  5. 25 6月, 2021 4 次提交
  7. 22 6月, 2021 1 次提交
  9. 17 6月, 2021 7 次提交
    • D
      net/mlx5e: Don't create devices during unload flow · a5ae8fc9
      由 Dmytro Linkin 提交于 
      Running devlink reload command for port in switchdev mode cause
resources to corrupt: driver can't release allocated EQ and reclaim
memory pages, because "rdma" auxiliary device had add CQs which blocks
EQ from deletion.
Erroneous sequence happens during reload-down phase, and is following:

1. detach device - suspends auxiliary devices which support it, destroys
   others. During this step "eth-rep" and "rdma-rep" are destroyed,
   "eth" - suspended.
2. disable SRIOV - moves device to legacy mode; as part of disablement -
   rescans drivers. This step adds "rdma" auxiliary device.
3. destroy EQ table - <failure>.

Driver shouldn't create any device during unload flows. To handle that
implement MLX5_PRIV_FLAGS_DETACH flag, set it on device detach and unset
on device attach. If flag is set do no-op on drivers rescan.

Fixes: a925b5e3 ("net/mlx5: Register mlx5 devices to auxiliary virtual bus")
Signed-off-by: NDmytro Linkin <dlinkin@nvidia.com>
Reviewed-by: NLeon Romanovsky <leonro@nvidia.com>
Reviewed-by: NRoi Dayan <roid@nvidia.com>
Signed-off-by: NSaeed Mahameed <saeedm@nvidia.com>
      a5ae8fc9
    • H
      mm/thp: unmap_mapping_page() to fix THP truncate_cleanup_page() · 22061a1f
      由 Hugh Dickins 提交于 
      There is a race between THP unmapping and truncation, when truncate sees
pmd_none() and skips the entry, after munmap's zap_huge_pmd() cleared
it, but before its page_remove_rmap() gets to decrement
compound_mapcount: generating false "BUG: Bad page cache" reports that
the page is still mapped when deleted.  This commit fixes that, but not
in the way I hoped.

The first attempt used try_to_unmap(page, TTU_SYNC|TTU_IGNORE_MLOCK)
instead of unmap_mapping_range() in truncate_cleanup_page(): it has
often been an annoyance that we usually call unmap_mapping_range() with
no pages locked, but there apply it to a single locked page.
try_to_unmap() looks more suitable for a single locked page.

However, try_to_unmap_one() contains a VM_BUG_ON_PAGE(!pvmw.pte,page):
it is used to insert THP migration entries, but not used to unmap THPs.
Copy zap_huge_pmd() and add THP handling now? Perhaps, but their TLB
needs are different, I'm too ignorant of the DAX cases, and couldn't
decide how far to go for anon+swap.  Set that aside.

The second attempt took a different tack: make no change in truncate.c,
but modify zap_huge_pmd() to insert an invalidated huge pmd instead of
clearing it initially, then pmd_clear() between page_remove_rmap() and
unlocking at the end.  Nice.  But powerpc blows that approach out of the
water, with its serialize_against_pte_lookup(), and interesting pgtable
usage.  It would need serious help to get working on powerpc (with a
minor optimization issue on s390 too).  Set that aside.

Just add an "if (page_mapped(page)) synchronize_rcu();" or other such
delay, after unmapping in truncate_cleanup_page()? Perhaps, but though
that's likely to reduce or eliminate the number of incidents, it would
give less assurance of whether we had identified the problem correctly.

This successful iteration introduces "unmap_mapping_page(page)" instead
of try_to_unmap(), and goes the usual unmap_mapping_range_tree() route,
with an addition to details.  Then zap_pmd_range() watches for this
case, and does spin_unlock(pmd_lock) if so - just like
page_vma_mapped_walk() now does in the PVMW_SYNC case.  Not pretty, but
safe.

Note that unmap_mapping_page() is doing a VM_BUG_ON(!PageLocked) to
assert its interface; but currently that's only used to make sure that
page->mapping is stable, and zap_pmd_range() doesn't care if the page is
locked or not.  Along these lines, in invalidate_inode_pages2_range()
move the initial unmap_mapping_range() out from under page lock, before
then calling unmap_mapping_page() under page lock if still mapped.

Link: https://lkml.kernel.org/r/a2a4a148-cdd8-942c-4ef8-51b77f643dbe@google.com
Fixes: fc127da0 ("truncate: handle file thp")
Signed-off-by: NHugh Dickins <hughd@google.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: NYang Shi <shy828301@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jue Wang <juew@google.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Wang Yugui <wangyugui@e16-tech.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      22061a1f
    • H
      mm/thp: try_to_unmap() use TTU_SYNC for safe splitting · 732ed558
      由 Hugh Dickins 提交于 
      Stressing huge tmpfs often crashed on unmap_page()'s VM_BUG_ON_PAGE
(!unmap_success): with dump_page() showing mapcount:1, but then its raw
struct page output showing _mapcount ffffffff i.e.  mapcount 0.

And even if that particular VM_BUG_ON_PAGE(!unmap_success) is removed,
it is immediately followed by a VM_BUG_ON_PAGE(compound_mapcount(head)),
and further down an IS_ENABLED(CONFIG_DEBUG_VM) total_mapcount BUG():
all indicative of some mapcount difficulty in development here perhaps.
But the !CONFIG_DEBUG_VM path handles the failures correctly and
silently.

I believe the problem is that once a racing unmap has cleared pte or
pmd, try_to_unmap_one() may skip taking the page table lock, and emerge
from try_to_unmap() before the racing task has reached decrementing
mapcount.

Instead of abandoning the unsafe VM_BUG_ON_PAGE(), and the ones that
follow, use PVMW_SYNC in try_to_unmap_one() in this case: adding
TTU_SYNC to the options, and passing that from unmap_page().

When CONFIG_DEBUG_VM, or for non-debug too? Consensus is to do the same
for both: the slight overhead added should rarely matter, except perhaps
if splitting sparsely-populated multiply-mapped shmem.  Once confident
that bugs are fixed, TTU_SYNC here can be removed, and the race
tolerated.

Link: https://lkml.kernel.org/r/c1e95853-8bcd-d8fd-55fa-e7f2488e78f@google.com
Fixes: fec89c10 ("thp: rewrite freeze_page()/unfreeze_page() with generic rmap walkers")
Signed-off-by: NHugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jue Wang <juew@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Wang Yugui <wangyugui@e16-tech.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      732ed558
    • H
      mm/thp: make is_huge_zero_pmd() safe and quicker · 3b77e8c8
      由 Hugh Dickins 提交于 
      Most callers of is_huge_zero_pmd() supply a pmd already verified
present; but a few (notably zap_huge_pmd()) do not - it might be a pmd
migration entry, in which the pfn is encoded differently from a present
pmd: which might pass the is_huge_zero_pmd() test (though not on x86,
since L1TF forced us to protect against that); or perhaps even crash in
pmd_page() applied to a swap-like entry.

Make it safe by adding pmd_present() check into is_huge_zero_pmd()
itself; and make it quicker by saving huge_zero_pfn, so that
is_huge_zero_pmd() will not need to do that pmd_page() lookup each time.

__split_huge_pmd_locked() checked pmd_trans_huge() before: that worked,
but is unnecessary now that is_huge_zero_pmd() checks present.

Link: https://lkml.kernel.org/r/21ea9ca-a1f5-8b90-5e88-95fb1c49bbfa@google.com
Fixes: e71769ae ("mm: enable thp migration for shmem thp")
Signed-off-by: NHugh Dickins <hughd@google.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: NYang Shi <shy828301@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jue Wang <juew@google.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Wang Yugui <wangyugui@e16-tech.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      3b77e8c8
    • M
      mm/hugetlb: expand restore_reserve_on_error functionality · 846be085
      由 Mike Kravetz 提交于 
      The routine restore_reserve_on_error is called to restore reservation
information when an error occurs after page allocation.  The routine
alloc_huge_page modifies the mapping reserve map and potentially the
reserve count during allocation.  If code calling alloc_huge_page
encounters an error after allocation and needs to free the page, the
reservation information needs to be adjusted.

Currently, restore_reserve_on_error only takes action on pages for which
the reserve count was adjusted(HPageRestoreReserve flag).  There is
nothing wrong with these adjustments.  However, alloc_huge_page ALWAYS
modifies the reserve map during allocation even if the reserve count is
not adjusted.  This can cause issues as observed during development of
this patch [1].

One specific series of operations causing an issue is:

 - Create a shared hugetlb mapping
   Reservations for all pages created by default

 - Fault in a page in the mapping
   Reservation exists so reservation count is decremented

 - Punch a hole in the file/mapping at index previously faulted
   Reservation and any associated pages will be removed

 - Allocate a page to fill the hole
   No reservation entry, so reserve count unmodified
   Reservation entry added to map by alloc_huge_page

 - Error after allocation and before instantiating the page
   Reservation entry remains in map

 - Allocate a page to fill the hole
   Reservation entry exists, so decrement reservation count

This will cause a reservation count underflow as the reservation count
was decremented twice for the same index.

A user would observe a very large number for HugePages_Rsvd in
/proc/meminfo.  This would also likely cause subsequent allocations of
hugetlb pages to fail as it would 'appear' that all pages are reserved.

This sequence of operations is unlikely to happen, however they were
easily reproduced and observed using hacked up code as described in [1].

Address the issue by having the routine restore_reserve_on_error take
action on pages where HPageRestoreReserve is not set.  In this case, we
need to remove any reserve map entry created by alloc_huge_page.  A new
helper routine vma_del_reservation assists with this operation.

There are three callers of alloc_huge_page which do not currently call
restore_reserve_on error before freeing a page on error paths.  Add
those missing calls.

[1] https://lore.kernel.org/linux-mm/20210528005029.88088-1-almasrymina@google.com/

Link: https://lkml.kernel.org/r/20210607204510.22617-1-mike.kravetz@oracle.com
Fixes: 96b96a96 ("mm/hugetlb: fix huge page reservation leak in private mapping error paths"
Signed-off-by: NMike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: NMina Almasry <almasrymina@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      846be085
    • P
      mm/swap: fix pte_same_as_swp() not removing uffd-wp bit when compare · 099dd687
      由 Peter Xu 提交于 
      I found it by pure code review, that pte_same_as_swp() of unuse_vma()
didn't take uffd-wp bit into account when comparing ptes.
pte_same_as_swp() returning false negative could cause failure to
swapoff swap ptes that was wr-protected by userfaultfd.

Link: https://lkml.kernel.org/r/20210603180546.9083-1-peterx@redhat.com
Fixes: f45ec5ff ("userfaultfd: wp: support swap and page migration")
Signed-off-by: NPeter Xu <peterx@redhat.com>
Acked-by: NHugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>	[5.7+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      099dd687
    • N
      mm,hwpoison: fix race with hugetlb page allocation · 25182f05
      由 Naoya Horiguchi 提交于 
      When hugetlb page fault (under overcommitting situation) and
memory_failure() race, VM_BUG_ON_PAGE() is triggered by the following
race:

    CPU0:                           CPU1:

                                    gather_surplus_pages()
                                      page = alloc_surplus_huge_page()
    memory_failure_hugetlb()
      get_hwpoison_page(page)
        __get_hwpoison_page(page)
          get_page_unless_zero(page)
                                      zero = put_page_testzero(page)
                                      VM_BUG_ON_PAGE(!zero, page)
                                      enqueue_huge_page(h, page)
      put_page(page)

__get_hwpoison_page() only checks the page refcount before taking an
additional one for memory error handling, which is not enough because
there's a time window where compound pages have non-zero refcount during
hugetlb page initialization.

So make __get_hwpoison_page() check page status a bit more for hugetlb
pages with get_hwpoison_huge_page().  Checking hugetlb-specific flags
under hugetlb_lock makes sure that the hugetlb page is not transitive.
It's notable that another new function, HWPoisonHandlable(), is helpful
to prevent a race against other transitive page states (like a generic
compound page just before PageHuge becomes true).

Link: https://lkml.kernel.org/r/20210603233632.2964832-2-nao.horiguchi@gmail.com
Fixes: ead07f6a ("mm/memory-failure: introduce get_hwpoison_page() for consistent refcount handling")
Signed-off-by: NNaoya Horiguchi <naoya.horiguchi@nec.com>
Reported-by: NMuchun Song <songmuchun@bytedance.com>
Acked-by: NMike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: <stable@vger.kernel.org>	[5.12+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      25182f05
  11. 16 6月, 2021 1 次提交
    • J
      ptp: improve max_adj check against unreasonable values · 475b92f9
      由 Jakub Kicinski 提交于 
      Scaled PPM conversion to PPB may (on 64bit systems) result
in a value larger than s32 can hold (freq/scaled_ppm is a long).
This means the kernel will not correctly reject unreasonably
high ->freq values (e.g. > 4294967295ppb, 281474976645 scaled PPM).

The conversion is equivalent to a division by ~66 (65.536),
so the value of ppb is always smaller than ppm, but not small
enough to assume narrowing the type from long -> s32 is okay.

Note that reasonable user space (e.g. ptp4l) will not use such
high values, anyway, 4289046510ppb ~= 4.3x, so the fix is
somewhat pedantic.

Fixes: d39a7435 ("ptp: validate the requested frequency adjustment.")
Fixes: d94ba80e ("ptp: Added a brand new class driver for ptp clocks.")
Signed-off-by: NJakub Kicinski <kuba@kernel.org>
Acked-by: NRichard Cochran <richardcochran@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      475b92f9
  13. 14 6月, 2021 1 次提交
  15. 13 6月, 2021 2 次提交
    • F
      mm: relocate 'write_protect_seq' in struct mm_struct · 2e302543
      由 Feng Tang 提交于 
      0day robot reported a 9.2% regression for will-it-scale mmap1 test
case[1], caused by commit 57efa1fe ("mm/gup: prevent gup_fast from
racing with COW during fork").

Further debug shows the regression is due to that commit changes the
offset of hot fields 'mmap_lock' inside structure 'mm_struct', thus some
cache alignment changes.

From the perf data, the contention for 'mmap_lock' is very severe and
takes around 95% cpu cycles, and it is a rw_semaphore

        struct rw_semaphore {
                atomic_long_t count;	/* 8 bytes */
                atomic_long_t owner;	/* 8 bytes */
                struct optimistic_spin_queue osq; /* spinner MCS lock */
                ...

Before commit 57efa1fe adds the 'write_protect_seq', it happens to
have a very optimal cache alignment layout, as Linus explained:

 "and before the addition of the 'write_protect_seq' field, the
  mmap_sem was at offset 120 in 'struct mm_struct'.

  Which meant that count and owner were in two different cachelines,
  and then when you have contention and spend time in
  rwsem_down_write_slowpath(), this is probably *exactly* the kind
  of layout you want.

  Because first the rwsem_write_trylock() will do a cmpxchg on the
  first cacheline (for the optimistic fast-path), and then in the
  case of contention, rwsem_down_write_slowpath() will just access
  the second cacheline.

  Which is probably just optimal for a load that spends a lot of
  time contended - new waiters touch that first cacheline, and then
  they queue themselves up on the second cacheline."

After the commit, the rw_semaphore is at offset 128, which means the
'count' and 'owner' fields are now in the same cacheline, and causes
more cache bouncing.

Currently there are 3 "#ifdef CONFIG_XXX" before 'mmap_lock' which will
affect its offset:

  CONFIG_MMU
  CONFIG_MEMBARRIER
  CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES

The layout above is on 64 bits system with 0day's default kernel config
(similar to RHEL-8.3's config), in which all these 3 options are 'y'.
And the layout can vary with different kernel configs.

Relayouting a structure is usually a double-edged sword, as sometimes it
can helps one case, but hurt other cases.  For this case, one solution
is, as the newly added 'write_protect_seq' is a 4 bytes long seqcount_t
(when CONFIG_DEBUG_LOCK_ALLOC=n), placing it into an existing 4 bytes
hole in 'mm_struct' will not change other fields' alignment, while
restoring the regression.

Link: https://lore.kernel.org/lkml/20210525031636.GB7744@xsang-OptiPlex-9020/ [1]
Reported-by: Nkernel test robot <oliver.sang@intel.com>
Signed-off-by: NFeng Tang <feng.tang@intel.com>
Reviewed-by: NJohn Hubbard <jhubbard@nvidia.com>
Reviewed-by: NJason Gunthorpe <jgg@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      2e302543
    • C
      net: make get_net_ns return error if NET_NS is disabled · ea6932d7
      由 Changbin Du 提交于 
      There is a panic in socket ioctl cmd SIOCGSKNS when NET_NS is not enabled.
The reason is that nsfs tries to access ns->ops but the proc_ns_operations
is not implemented in this case.

[7.670023] Unable to handle kernel NULL pointer dereference at virtual address 00000010
[7.670268] pgd = 32b54000
[7.670544] [00000010] *pgd=00000000
[7.671861] Internal error: Oops: 5 [#1] SMP ARM
[7.672315] Modules linked in:
[7.672918] CPU: 0 PID: 1 Comm: systemd Not tainted 5.13.0-rc3-00375-g6799d4f2 #16
[7.673309] Hardware name: Generic DT based system
[7.673642] PC is at nsfs_evict+0x24/0x30
[7.674486] LR is at clear_inode+0x20/0x9c

The same to tun SIOCGSKNS command.

To fix this problem, we make get_net_ns() return -EINVAL when NET_NS is
disabled. Meanwhile move it to right place net/core/net_namespace.c.
Signed-off-by: NChangbin Du <changbin.du@gmail.com>
Fixes: c62cce2c ("net: add an ioctl to get a socket network namespace")
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Suggested-by: NJakub Kicinski <kuba@kernel.org>
Acked-by: NChristian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      ea6932d7
  17. 10 6月, 2021 2 次提交
    • D
      net/mlx5e: Fix page reclaim for dead peer hairpin · a3e5fd93
      由 Dima Chumak 提交于 
      When adding a hairpin flow, a firmware-side send queue is created for
the peer net device, which claims some host memory pages for its
internal ring buffer. If the peer net device is removed/unbound before
the hairpin flow is deleted, then the send queue is not destroyed which
leads to a stack trace on pci device remove:

[ 748.005230] mlx5_core 0000:08:00.2: wait_func:1094:(pid 12985): MANAGE_PAGES(0x108) timeout. Will cause a leak of a command resource
[ 748.005231] mlx5_core 0000:08:00.2: reclaim_pages:514:(pid 12985): failed reclaiming pages: err -110
[ 748.001835] mlx5_core 0000:08:00.2: mlx5_reclaim_root_pages:653:(pid 12985): failed reclaiming pages (-110) for func id 0x0
[ 748.002171] ------------[ cut here ]------------
[ 748.001177] FW pages counter is 4 after reclaiming all pages
[ 748.001186] WARNING: CPU: 1 PID: 12985 at drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c:685 mlx5_reclaim_startup_pages+0x34b/0x460 [mlx5_core]                      [  +0.002771] Modules linked in: cls_flower mlx5_ib mlx5_core ptp pps_core act_mirred sch_ingress openvswitch nsh xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink xt_addrtype iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 br_netfilter rpcrdma rdma_ucm ib_iser libiscsi scsi_transport_iscsi rdma_cm ib_umad ib_ipoib iw_cm ib_cm ib_uverbs ib_core overlay fuse [last unloaded: pps_core]
[ 748.007225] CPU: 1 PID: 12985 Comm: tee Not tainted 5.12.0+ #1
[ 748.001376] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
[ 748.002315] RIP: 0010:mlx5_reclaim_startup_pages+0x34b/0x460 [mlx5_core]
[ 748.001679] Code: 28 00 00 00 0f 85 22 01 00 00 48 81 c4 b0 00 00 00 31 c0 5b 5d 41 5c 41 5d 41 5e 41 5f c3 48 c7 c7 40 cc 19 a1 e8 9f 71 0e e2 <0f> 0b e9 30 ff ff ff 48 c7 c7 a0 cc 19 a1 e8 8c 71 0e e2 0f 0b e9
[ 748.003781] RSP: 0018:ffff88815220faf8 EFLAGS: 00010286
[ 748.001149] RAX: 0000000000000000 RBX: ffff8881b4900280 RCX: 0000000000000000
[ 748.001445] RDX: 0000000000000027 RSI: 0000000000000004 RDI: ffffed102a441f51
[ 748.001614] RBP: 00000000000032b9 R08: 0000000000000001 R09: ffffed1054a15ee8
[ 748.001446] R10: ffff8882a50af73b R11: ffffed1054a15ee7 R12: fffffbfff07c1e30
[ 748.001447] R13: dffffc0000000000 R14: ffff8881b492cba8 R15: 0000000000000000
[ 748.001429] FS:  00007f58bd08b580(0000) GS:ffff8882a5080000(0000) knlGS:0000000000000000
[ 748.001695] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 748.001309] CR2: 000055a026351740 CR3: 00000001d3b48006 CR4: 0000000000370ea0
[ 748.001506] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 748.001483] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 748.001654] Call Trace:
[ 748.000576]  ? mlx5_satisfy_startup_pages+0x290/0x290 [mlx5_core]
[ 748.001416]  ? mlx5_cmd_teardown_hca+0xa2/0xd0 [mlx5_core]
[ 748.001354]  ? mlx5_cmd_init_hca+0x280/0x280 [mlx5_core]
[ 748.001203]  mlx5_function_teardown+0x30/0x60 [mlx5_core]
[ 748.001275]  mlx5_uninit_one+0xa7/0xc0 [mlx5_core]
[ 748.001200]  remove_one+0x5f/0xc0 [mlx5_core]
[ 748.001075]  pci_device_remove+0x9f/0x1d0
[ 748.000833]  device_release_driver_internal+0x1e0/0x490
[ 748.001207]  unbind_store+0x19f/0x200
[ 748.000942]  ? sysfs_file_ops+0x170/0x170
[ 748.001000]  kernfs_fop_write_iter+0x2bc/0x450
[ 748.000970]  new_sync_write+0x373/0x610
[ 748.001124]  ? new_sync_read+0x600/0x600
[ 748.001057]  ? lock_acquire+0x4d6/0x700
[ 748.000908]  ? lockdep_hardirqs_on_prepare+0x400/0x400
[ 748.001126]  ? fd_install+0x1c9/0x4d0
[ 748.000951]  vfs_write+0x4d0/0x800
[ 748.000804]  ksys_write+0xf9/0x1d0
[ 748.000868]  ? __x64_sys_read+0xb0/0xb0
[ 748.000811]  ? filp_open+0x50/0x50
[ 748.000919]  ? syscall_enter_from_user_mode+0x1d/0x50
[ 748.001223]  do_syscall_64+0x3f/0x80
[ 748.000892]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 748.001026] RIP: 0033:0x7f58bcfb22f7
[ 748.000944] Code: 0d 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24
[ 748.003925] RSP: 002b:00007fffd7f2aaa8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 748.001732] RAX: ffffffffffffffda RBX: 000000000000000d RCX: 00007f58bcfb22f7
[ 748.001426] RDX: 000000000000000d RSI: 00007fffd7f2abc0 RDI: 0000000000000003
[ 748.001746] RBP: 00007fffd7f2abc0 R08: 0000000000000000 R09: 0000000000000001
[ 748.001631] R10: 00000000000001b6 R11: 0000000000000246 R12: 000000000000000d
[ 748.001537] R13: 00005597ac2c24a0 R14: 000000000000000d R15: 00007f58bd084700
[ 748.001564] irq event stamp: 0
[ 748.000787] hardirqs last  enabled at (0): [<0000000000000000>] 0x0
[ 748.001399] hardirqs last disabled at (0): [<ffffffff813132cf>] copy_process+0x146f/0x5eb0
[ 748.001854] softirqs last  enabled at (0): [<ffffffff8131330e>] copy_process+0x14ae/0x5eb0
[ 748.013431] softirqs last disabled at (0): [<0000000000000000>] 0x0
[ 748.001492] ---[ end trace a6fabd773d1c51ae ]---

Fix by destroying the send queue of a hairpin peer net device that is
being removed/unbound, which returns the allocated ring buffer pages to
the host.

Fixes: 4d8fcf21 ("net/mlx5e: Avoid unbounded peer devices when unpairing TC hairpin rules")
Signed-off-by: NDima Chumak <dchumak@nvidia.com>
Reviewed-by: NRoi Dayan <roid@nvidia.com>
Signed-off-by: NSaeed Mahameed <saeedm@nvidia.com>
      a3e5fd93
    • R
      misc: rtsx: separate aspm mode into MODE_REG and MODE_CFG · 3df4fce7
      由 Ricky Wu 提交于 
      aspm (Active State Power Management)
rtsx_comm_set_aspm: this function is for driver to make sure
not enter power saving when processing of init and card_detcct
ASPM_MODE_CFG: 8411 5209 5227 5229 5249 5250
Change back to use original way to control aspm
ASPM_MODE_REG: 5227A 524A 5250A 5260 5261 5228
Keep the new way to control aspm

Fixes: 121e9c6b ("misc: rtsx: modify and fix init_hw function")
Reported-by: NChris Chiu <chris.chiu@canonical.com>
Tested-by: NGordon Lack <gordon.lack@dsl.pipex.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NRicky Wu <ricky_wu@realtek.com>
Link: https://lore.kernel.org/r/20210607101634.4948-1-ricky_wu@realtek.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      3df4fce7
  19. 09 6月, 2021 2 次提交
    • P
      kvm: fix previous commit for 32-bit builds · 4422829e
      由 Paolo Bonzini 提交于 
      array_index_nospec does not work for uint64_t on 32-bit builds.
However, the size of a memory slot must be less than 20 bits wide
on those system, since the memory slot must fit in the user
address space.  So just store it in an unsigned long.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      4422829e
    • P
      kvm: avoid speculation-based attacks from out-of-range memslot accesses · da27a83f
      由 Paolo Bonzini 提交于 
      KVM's mechanism for accessing guest memory translates a guest physical
address (gpa) to a host virtual address using the right-shifted gpa
(also known as gfn) and a struct kvm_memory_slot.  The translation is
performed in __gfn_to_hva_memslot using the following formula:

      hva = slot->userspace_addr + (gfn - slot->base_gfn) * PAGE_SIZE

It is expected that gfn falls within the boundaries of the guest's
physical memory.  However, a guest can access invalid physical addresses
in such a way that the gfn is invalid.

__gfn_to_hva_memslot is called from kvm_vcpu_gfn_to_hva_prot, which first
retrieves a memslot through __gfn_to_memslot.  While __gfn_to_memslot
does check that the gfn falls within the boundaries of the guest's
physical memory or not, a CPU can speculate the result of the check and
continue execution speculatively using an illegal gfn. The speculation
can result in calculating an out-of-bounds hva.  If the resulting host
virtual address is used to load another guest physical address, this
is effectively a Spectre gadget consisting of two consecutive reads,
the second of which is data dependent on the first.

Right now it's not clear if there are any cases in which this is
exploitable.  One interesting case was reported by the original author
of this patch, and involves visiting guest page tables on x86.  Right
now these are not vulnerable because the hva read goes through get_user(),
which contains an LFENCE speculation barrier.  However, there are
patches in progress for x86 uaccess.h to mask kernel addresses instead of
using LFENCE; once these land, a guest could use speculation to read
from the VMM's ring 3 address space.  Other architectures such as ARM
already use the address masking method, and would be susceptible to
this same kind of data-dependent access gadgets.  Therefore, this patch
proactively protects from these attacks by masking out-of-bounds gfns
in __gfn_to_hva_memslot, which blocks speculation of invalid hvas.

Sean Christopherson noted that this patch does not cover
kvm_read_guest_offset_cached.  This however is limited to a few bytes
past the end of the cache, and therefore it is unlikely to be useful in
the context of building a chain of data dependent accesses.
Reported-by: NArtemiy Margaritov <artemiy.margaritov@gmail.com>
Co-developed-by: NArtemiy Margaritov <artemiy.margaritov@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      da27a83f
  21. 05 6月, 2021 1 次提交
  23. 04 6月, 2021 3 次提交
  25. 03 6月, 2021 1 次提交
    • D
      sched/fair: Fix util_est UTIL_AVG_UNCHANGED handling · 68d7a190
      由 Dietmar Eggemann 提交于 
      The util_est internal UTIL_AVG_UNCHANGED flag which is used to prevent
unnecessary util_est updates uses the LSB of util_est.enqueued. It is
exposed via _task_util_est() (and task_util_est()).

Commit 92a801e5 ("sched/fair: Mask UTIL_AVG_UNCHANGED usages")
mentions that the LSB is lost for util_est resolution but
find_energy_efficient_cpu() checks if task_util_est() returns 0 to
return prev_cpu early.

_task_util_est() returns the max value of util_est.ewma and
util_est.enqueued or'ed w/ UTIL_AVG_UNCHANGED.
So task_util_est() returning the max of task_util() and
_task_util_est() will never return 0 under the default
SCHED_FEAT(UTIL_EST, true).

To fix this use the MSB of util_est.enqueued instead and keep the flag
util_est internal, i.e. don't export it via _task_util_est().

The maximal possible util_avg value for a task is 1024 so the MSB of
'unsigned int util_est.enqueued' isn't used to store a util value.

As a caveat the code behind the util_est_se trace point has to filter
UTIL_AVG_UNCHANGED to see the real util_est.enqueued value which should
be easy to do.

This also fixes an issue report by Xuewen Yan that util_est_update()
only used UTIL_AVG_UNCHANGED for the subtrahend of the equation:

  last_enqueued_diff = ue.enqueued - (task_util() | UTIL_AVG_UNCHANGED)

Fixes: b89997aa sched/pelt: Fix task util_est update filtering
Signed-off-by: NDietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NXuewen Yan <xuewen.yan@unisoc.com>
Reviewed-by: NVincent Donnefort <vincent.donnefort@arm.com>
Reviewed-by: NVincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20210602145808.1562603-1-dietmar.eggemann@arm.com
      68d7a190
  27. 02 6月, 2021 2 次提交
  29. 01 6月, 2021 1 次提交
  31. 31 5月, 2021 1 次提交
  33. 27 5月, 2021 3 次提交
  35. 26 5月, 2021 2 次提交
  37. 25 5月, 2021 3 次提交
  39. 24 5月, 2021 1 次提交