linux-stable.git/mm/memory.c, branch v4.18.7

mm/tlb: Remove tlb_remove_table() non-concurrent condition

2018-09-09T08:32:38+00:00

commit a6f572084fbee8b30f91465f4a085d7a90901c57 upstream.

Will noted that only checking mm_users is incorrect; we should also
check mm_count in order to cover CPUs that have a lazy reference to
this mm (and could do speculative TLB operations).

If removing this turns out to be a performance issue, we can
re-instate a more complete check, but in tlb_table_flush() eliding the
call_rcu_sched().

Fixes: 267239116987 ("mm, powerpc: move the RCU page-table freeing into generic code")
Reported-by: Will Deacon 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Rik van Riel 
Acked-by: Will Deacon 
Cc: Nicholas Piggin 
Cc: David Miller 
Cc: Martin Schwidefsky 
Cc: Michael Ellerman 
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

mm/tlb, x86/mm: Support invalidating TLB caches for RCU_TABLE_FREE

2018-09-05T07:29:47+00:00

commit d86564a2f085b79ec046a5cba90188e612352806 upstream.

Jann reported that x86 was missing required TLB invalidates when he
hit the !*batch slow path in tlb_remove_table().

This is indeed the case; RCU_TABLE_FREE does not provide TLB (cache)
invalidates, the PowerPC-hash where this code originated and the
Sparc-hash where this was subsequently used did not need that. ARM
which later used this put an explicit TLB invalidate in their
__p*_free_tlb() functions, and PowerPC-radix followed that example.

But when we hooked up x86 we failed to consider this. Fix this by
(optionally) hooking tlb_remove_table() into the TLB invalidate code.

NOTE: s390 was also needing something like this and might now
      be able to use the generic code again.

[ Modified to be on top of Nick's cleanups, which simplified this patch
  now that tlb_flush_mmu_tlbonly() really only flushes the TLB - Linus ]

Fixes: 9e52fc2b50de ("x86/mm: Enable RCU based page table freeing (CONFIG_HAVE_RCU_TABLE_FREE=y)")
Reported-by: Jann Horn 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Rik van Riel 
Cc: Nicholas Piggin 
Cc: David Miller 
Cc: Will Deacon 
Cc: Martin Schwidefsky 
Cc: Michael Ellerman 
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

mm: move tlb_table_flush to tlb_flush_mmu_free

2018-09-05T07:29:47+00:00

commit db7ddef301128dad394f1c0f77027f86ee9a4edb upstream.

There is no need to call this from tlb_flush_mmu_tlbonly, it logically
belongs with tlb_flush_mmu_free.  This makes future fixes simpler.

[ This was originally done to allow code consolidation for the
  mmu_notifier fix, but it also ends up helping simplify the
  HAVE_RCU_TABLE_INVALIDATE fix.    - Linus ]

Signed-off-by: Nicholas Piggin 
Acked-by: Will Deacon 
Cc: Peter Zijlstra 
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

x86/speculation/l1tf: Disallow non privileged high MMIO PROT_NONE mappings

2018-08-15T15:37:25+00:00

commit 42e4089c7890725fcd329999252dc489b72f2921 upstream.

For L1TF PROT_NONE mappings are protected by inverting the PFN in the page
table entry. This sets the high bits in the CPU's address space, thus
making sure to point to not point an unmapped entry to valid cached memory.

Some server system BIOSes put the MMIO mappings high up in the physical
address space. If such an high mapping was mapped to unprivileged users
they could attack low memory by setting such a mapping to PROT_NONE. This
could happen through a special device driver which is not access
protected. Normal /dev/mem is of course access protected.

To avoid this forbid PROT_NONE mappings or mprotect for high MMIO mappings.

Valid page mappings are allowed because the system is then unsafe anyways.

It's not expected that users commonly use PROT_NONE on MMIO. But to
minimize any impact this is only enforced if the mapping actually refers to
a high MMIO address (defined as the MAX_PA-1 bit being set), and also skip
the check for root.

For mmaps this is straight forward and can be handled in vm_insert_pfn and
in remap_pfn_range().

For mprotect it's a bit trickier. At the point where the actual PTEs are
accessed a lot of state has been changed and it would be difficult to undo
on an error. Since this is a uncommon case use a separate early page talk
walk pass for MMIO PROT_NONE mappings that checks for this condition
early. For non MMIO and non PROT_NONE there are no changes.

Signed-off-by: Andi Kleen 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Josh Poimboeuf 
Acked-by: Dave Hansen 
Signed-off-by: Greg Kroah-Hartman

mm/memory.c: check return value of ioremap_prot

2018-08-11T03:19:58+00:00

ioremap_prot() can return NULL which could lead to an oops.

Link: http://lkml.kernel.org/r/1533195441-58594-1-git-send-email-chenjie6@huawei.com
Signed-off-by: chen jie 
Reviewed-by: Andrew Morton 
Cc: Li Zefan 
Cc: chenjie 
Cc: Yang Shi 
Cc: Alexey Dobriyan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: delete historical BUG from zap_pmd_range()

2018-08-01T19:23:45+00:00

Delete the old VM_BUG_ON_VMA() from zap_pmd_range(), which asserted
that mmap_sem must be held when splitting an "anonymous" vma there.
Whether that's still strictly true nowadays is not entirely clear,
but the danger of sometimes crashing on the BUG is now fairly clear.

Even with the new stricter rules for anonymous vma marking, the
condition it checks for can possible trigger. Commit 44960f2a7b63
("staging: ashmem: Fix SIGBUS crash when traversing mmaped ashmem
pages") is good, and originally I thought it was safe from that
VM_BUG_ON_VMA(), because the /dev/ashmem fd exposed to the user is
disconnected from the vm_file in the vma, and madvise(,,MADV_REMOVE)
insists on VM_SHARED.

But after I read John's earlier mail, drawing attention to the
vfs_fallocate() in there: I may be wrong, and I don't know if Android
has THP in the config anyway, but it looks to me like an
unmap_mapping_range() from ashmem's vfs_fallocate() could hit precisely
the VM_BUG_ON_VMA(), once it's vma_is_anonymous().

Signed-off-by: Hugh Dickins 
Cc: John Stultz 
Cc: Kirill Shutemov 
Cc: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'akpm' (patches from Andrew)

2018-06-08T01:39:37+00:00

Merge updates from Andrew Morton:

 - a few misc things

 - ocfs2 updates

 - v9fs updates

 - MM

 - procfs updates

 - lib/ updates

 - autofs updates

* emailed patches from Andrew Morton : (118 commits)
  autofs: small cleanup in autofs_getpath()
  autofs: clean up includes
  autofs: comment on selinux changes needed for module autoload
  autofs: update MAINTAINERS entry for autofs
  autofs: use autofs instead of autofs4 in documentation
  autofs: rename autofs documentation files
  autofs: create autofs Kconfig and Makefile
  autofs: delete fs/autofs4 source files
  autofs: update fs/autofs4/Makefile
  autofs: update fs/autofs4/Kconfig
  autofs: copy autofs4 to autofs
  autofs4: use autofs instead of autofs4 everywhere
  autofs4: merge auto_fs.h and auto_fs4.h
  fs/binfmt_misc.c: do not allow offset overflow
  checkpatch: improve patch recognition
  lib/ucs2_string.c: add MODULE_LICENSE()
  lib/mpi: headers cleanup
  lib/percpu_ida.c: use _irqsave() instead of local_irq_save() + spin_lock
  lib/idr.c: remove simple_ida_lock
  lib/bitmap.c: micro-optimization for __bitmap_complement()
  ...

mm: remove odd HAVE_PTE_SPECIAL

2018-06-08T00:34:35+00:00

Remove the additional define HAVE_PTE_SPECIAL and rely directly on
CONFIG_ARCH_HAS_PTE_SPECIAL.

There is no functional change introduced by this patch

Link: http://lkml.kernel.org/r/1523533733-25437-1-git-send-email-ldufour@linux.vnet.ibm.com
Signed-off-by: Laurent Dufour 
Acked-by: David Rientjes 
Reviewed-by: Andrew Morton 
Cc: Jerome Glisse 
Cc: Michal Hocko 
Cc: Christophe LEROY 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: introduce ARCH_HAS_PTE_SPECIAL

2018-06-08T00:34:35+00:00

Currently the PTE special supports is turned on in per architecture
header files.  Most of the time, it is defined in
arch/*/include/asm/pgtable.h depending or not on some other per
architecture static definition.

This patch introduce a new configuration variable to manage this
directly in the Kconfig files.  It would later replace
__HAVE_ARCH_PTE_SPECIAL.

Here notes for some architecture where the definition of
__HAVE_ARCH_PTE_SPECIAL is not obvious:

arm
 __HAVE_ARCH_PTE_SPECIAL which is currently defined in
arch/arm/include/asm/pgtable-3level.h which is included by
arch/arm/include/asm/pgtable.h when CONFIG_ARM_LPAE is set.
So select ARCH_HAS_PTE_SPECIAL if ARM_LPAE.

powerpc
__HAVE_ARCH_PTE_SPECIAL is defined in 2 files:
 - arch/powerpc/include/asm/book3s/64/pgtable.h
 - arch/powerpc/include/asm/pte-common.h
The first one is included if (PPC_BOOK3S & PPC64) while the second is
included in all the other cases.
So select ARCH_HAS_PTE_SPECIAL all the time.

sparc:
__HAVE_ARCH_PTE_SPECIAL is defined if defined(__sparc__) &&
defined(__arch64__) which are defined through the compiler in
sparc/Makefile if !SPARC32 which I assume to be if SPARC64.
So select ARCH_HAS_PTE_SPECIAL if SPARC64

There is no functional change introduced by this patch.

Link: http://lkml.kernel.org/r/1523433816-14460-2-git-send-email-ldufour@linux.vnet.ibm.com
Signed-off-by: Laurent Dufour 
Suggested-by: Jerome Glisse 
Reviewed-by: Jerome Glisse 
Acked-by: David Rientjes 
Cc: Michal Hocko 
Cc: "Aneesh Kumar K . V" 
Cc: Michael Ellerman 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Jonathan Corbet 
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Yoshinori Sato 
Cc: Rich Felker 
Cc: David S. Miller 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Vineet Gupta 
Cc: Palmer Dabbelt 
Cc: Albert Ou 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: David Rientjes 
Cc: Robin Murphy 
Cc: Christophe LEROY 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fs/dax.c: use new return type vm_fault_t

2018-06-08T00:34:33+00:00

Use new return type vm_fault_t for fault handler.  For now, this is just
documenting that the function returns a VM_FAULT value rather than an
errno.  Once all instances are converted, vm_fault_t will become a
distinct type.

commit 1c8f422059ae ("mm: change return type to vm_fault_t")

There was an existing bug inside dax_load_hole() if vm_insert_mixed had
failed to allocate a page table, we'd return VM_FAULT_NOPAGE instead of
VM_FAULT_OOM.  With new vmf_insert_mixed() this issue is addressed.

vm_insert_mixed_mkwrite has inefficiency when it returns an error value,
driver has to convert it to vm_fault_t type.  With new
vmf_insert_mixed_mkwrite() this limitation will be addressed.

Link: http://lkml.kernel.org/r/20180510181121.GA15239@jordon-HP-15-Notebook-PC
Signed-off-by: Souptick Joarder 
Reviewed-by: Jan Kara 
Reviewed-by: Matthew Wilcox 
Reviewed-by: Ross Zwisler 
Cc: Alexander Viro 
Cc: Dan Williams 
Cc: Michal Hocko 
Cc: "Kirill A. Shutemov" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds