linux-stable.git/mm, branch v6.6.7

mm/memory_hotplug: fix error handling in add_memory_resource()

2023-12-13T17:45:25+00:00

commit f42ce5f087eb69e47294ababd2e7e6f88a82d308 upstream.

In add_memory_resource(), creation of memory block devices occurs after
successful call to arch_add_memory().  However, creation of memory block
devices could fail.  In that case, arch_remove_memory() is called to
perform necessary cleanup.

Currently with or without altmap support, arch_remove_memory() is always
passed with altmap set to NULL during error handling.  This leads to
freeing of struct pages using free_pages(), eventhough the allocation
might have been performed with altmap support via
altmap_alloc_block_buf().

Fix the error handling by passing altmap in arch_remove_memory(). This
ensures the following:
* When altmap is disabled, deallocation of the struct pages array occurs
  via free_pages().
* When altmap is enabled, deallocation occurs via vmem_altmap_free().

Link: https://lkml.kernel.org/r/20231120145354.308999-3-sumanthk@linux.ibm.com
Fixes: a08a2ae34613 ("mm,memory_hotplug: allocate memmap from the added memory range")
Signed-off-by: Sumanth Korikkar 
Reviewed-by: Gerald Schaefer 
Acked-by: David Hildenbrand 
Cc: Alexander Gordeev 
Cc: Aneesh Kumar K.V 
Cc: Anshuman Khandual 
Cc: Heiko Carstens 
Cc: kernel test robot 
Cc: Michal Hocko 
Cc: Oscar Salvador 
Cc: Vasily Gorbik 
Cc: 	[5.15+]
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

mm: fix oops when filemap_map_pmd() without prealloc_pte

2023-12-13T17:45:25+00:00

commit 9aa1345d66b8132745ffb99b348b1492088da9e2 upstream.

syzbot reports oops in lockdep's __lock_acquire(), called from
__pte_offset_map_lock() called from filemap_map_pages(); or when I run the
repro, the oops comes in pmd_install(), called from filemap_map_pmd()
called from filemap_map_pages(), just before the __pte_offset_map_lock().

The problem is that filemap_map_pmd() has been assuming that when it finds
pmd_none(), a page table has already been prepared in prealloc_pte; and
indeed do_fault_around() has been careful to preallocate one there, when
it finds pmd_none(): but what if *pmd became none in between?

My 6.6 mods in mm/khugepaged.c, avoiding mmap_lock for write, have made it
easy for *pmd to be cleared while servicing a page fault; but even before
those, a huge *pmd might be zapped while a fault is serviced.

The difference in symptomatic stack traces comes from the "memory model"
in use: pmd_install() uses pmd_populate() uses page_to_pfn(): in some
models that is strict, and will oops on the NULL prealloc_pte; in other
models, it will construct a bogus value to be populated into *pmd, then
__pte_offset_map_lock() oops when trying to access split ptlock pointer
(or some other symptom in normal case of ptlock embedded not pointer).

Link: https://lore.kernel.org/linux-mm/20231115065506.19780-1-jose.pekkarinen@foxhound.fi/
Link: https://lkml.kernel.org/r/6ed0c50c-78ef-0719-b3c5-60c0c010431c@google.com
Fixes: f9ce0be71d1f ("mm: Cleanup faultaround and finish_fault() codepaths")
Signed-off-by: Hugh Dickins 
Reported-and-tested-by: syzbot+89edd67979b52675ddec@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-mm/0000000000005e44550608a0806c@google.com/
Reviewed-by: David Hildenbrand 
Cc: Jann Horn ,
Cc: José Pekkarinen 
Cc: Kirill A. Shutemov 
Cc: Matthew Wilcox (Oracle) 
Cc:     [5.12+]
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

mm/memory_hotplug: add missing mem_hotplug_lock

2023-12-13T17:45:24+00:00

commit 001002e73712cdf6b8d9a103648cda3040ad7647 upstream.

From Documentation/core-api/memory-hotplug.rst:
When adding/removing/onlining/offlining memory or adding/removing
heterogeneous/device memory, we should always hold the mem_hotplug_lock
in write mode to serialise memory hotplug (e.g. access to global/zone
variables).

mhp_(de)init_memmap_on_memory() functions can change zone stats and
struct page content, but they are currently called w/o the
mem_hotplug_lock.

When memory block is being offlined and when kmemleak goes through each
populated zone, the following theoretical race conditions could occur:
CPU 0:					     | CPU 1:
memory_offline()			     |
-> offline_pages()			     |
	-> mem_hotplug_begin()		     |
	   ...				     |
	-> mem_hotplug_done()		     |
					     | kmemleak_scan()
					     | -> get_online_mems()
					     |    ...
-> mhp_deinit_memmap_on_memory()	     |
  [not protected by mem_hotplug_begin/done()]|
  Marks memory section as offline,	     |   Retrieves zone_start_pfn
  poisons vmemmap struct pages and updates   |   and struct page members.
  the zone related data			     |
   					     |    ...
   					     | -> put_online_mems()

Fix this by ensuring mem_hotplug_lock is taken before performing
mhp_init_memmap_on_memory().  Also ensure that
mhp_deinit_memmap_on_memory() holds the lock.

online/offline_pages() are currently only called from
memory_block_online/offline(), so it is safe to move the locking there.

Link: https://lkml.kernel.org/r/20231120145354.308999-2-sumanthk@linux.ibm.com
Fixes: a08a2ae34613 ("mm,memory_hotplug: allocate memmap from the added memory range")
Signed-off-by: Sumanth Korikkar 
Reviewed-by: Gerald Schaefer 
Acked-by: David Hildenbrand 
Cc: Alexander Gordeev 
Cc: Aneesh Kumar K.V 
Cc: Anshuman Khandual 
Cc: Heiko Carstens 
Cc: Michal Hocko 
Cc: Oscar Salvador 
Cc: Vasily Gorbik 
Cc: kernel test robot 
Cc: 	[5.15+]
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

hugetlb: fix null-ptr-deref in hugetlb_vma_lock_write

2023-12-13T17:45:24+00:00

commit 187da0f8250aa94bd96266096aef6f694e0b4cd2 upstream.

The routine __vma_private_lock tests for the existence of a reserve map
associated with a private hugetlb mapping.  A pointer to the reserve map
is in vma->vm_private_data.  __vma_private_lock was checking the pointer
for NULL.  However, it is possible that the low bits of the pointer could
be used as flags.  In such instances, vm_private_data is not NULL and not
a valid pointer.  This results in the null-ptr-deref reported by syzbot:

general protection fault, probably for non-canonical address 0xdffffc000000001d:
 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef]
CPU: 0 PID: 5048 Comm: syz-executor139 Not tainted 6.6.0-rc7-syzkaller-00142-g88
8cf78c29e2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 1
0/09/2023
RIP: 0010:__lock_acquire+0x109/0x5de0 kernel/locking/lockdep.c:5004
...
Call Trace:
 
 lock_acquire kernel/locking/lockdep.c:5753 [inline]
 lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5718
 down_write+0x93/0x200 kernel/locking/rwsem.c:1573
 hugetlb_vma_lock_write mm/hugetlb.c:300 [inline]
 hugetlb_vma_lock_write+0xae/0x100 mm/hugetlb.c:291
 __hugetlb_zap_begin+0x1e9/0x2b0 mm/hugetlb.c:5447
 hugetlb_zap_begin include/linux/hugetlb.h:258 [inline]
 unmap_vmas+0x2f4/0x470 mm/memory.c:1733
 exit_mmap+0x1ad/0xa60 mm/mmap.c:3230
 __mmput+0x12a/0x4d0 kernel/fork.c:1349
 mmput+0x62/0x70 kernel/fork.c:1371
 exit_mm kernel/exit.c:567 [inline]
 do_exit+0x9ad/0x2a20 kernel/exit.c:861
 __do_sys_exit kernel/exit.c:991 [inline]
 __se_sys_exit kernel/exit.c:989 [inline]
 __x64_sys_exit+0x42/0x50 kernel/exit.c:989
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Mask off low bit flags before checking for NULL pointer.  In addition, the
reserve map only 'belongs' to the OWNER (parent in parent/child
relationships) so also check for the OWNER flag.

Link: https://lkml.kernel.org/r/20231114012033.259600-1-mike.kravetz@oracle.com
Reported-by: syzbot+6ada951e7c0f7bc8a71e@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-mm/00000000000078d1e00608d7878b@google.com/
Fixes: bf4916922c60 ("hugetlbfs: extend hugetlb_vma_lock to private VMAs")
Signed-off-by: Mike Kravetz 
Reviewed-by: Rik van Riel 
Cc: Edward Adam Davis 
Cc: Muchun Song 
Cc: Nathan Chancellor 
Cc: Nick Desaulniers 
Cc: Tom Rix 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

mm/damon/sysfs: eliminate potential uninitialized variable warning

2023-12-13T17:45:11+00:00

[ Upstream commit 85c2ceaafbd306814a3a4740bf4d95ac26a8b36a ]

The "err" variable is not initialized if damon_target_has_pid(ctx) is
false and sys_target->regions->nr is zero.

Link: https://lkml.kernel.org/r/739e6aaf-a634-4e33-98a8-16546379ec9f@moroto.mountain
Fixes: 0bcd216c4741 ("mm/damon/sysfs: update monitoring target regions for online input commit")
Signed-off-by: Dan Carpenter 
Reviewed-by: SeongJae Park 
Signed-off-by: Andrew Morton 
Signed-off-by: Sasha Levin

filemap: add a per-mapping stable writes flag

2023-12-03T06:33:03+00:00

[ Upstream commit 762321dab9a72760bf9aec48362f932717c9424d ]

folio_wait_stable waits for writeback to finish before modifying the
contents of a folio again, e.g. to support check summing of the data
in the block integrity code.

Currently this behavior is controlled by the SB_I_STABLE_WRITES flag
on the super_block, which means it is uniform for the entire file system.
This is wrong for the block device pseudofs which is shared by all
block devices, or file systems that can use multiple devices like XFS
witht the RT subvolume or btrfs (although btrfs currently reimplements
folio_wait_stable anyway).

Add a per-address_space AS_STABLE_WRITES flag to control the behavior
in a more fine grained way.  The existing SB_I_STABLE_WRITES is kept
to initialize AS_STABLE_WRITES to the existing default which covers
most cases.

Signed-off-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20231025141020.192413-2-hch@lst.de
Tested-by: Ilya Dryomov 
Reviewed-by: Matthew Wilcox (Oracle) 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Christian Brauner 
Stable-dep-of: 1898efcdbed3 ("block: update the stable_writes flag in bdev_add")
Signed-off-by: Sasha Levin

mm: kmem: drop __GFP_NOFAIL when allocating objcg vectors

2023-11-28T17:20:13+00:00

commit 24948e3b7b12e0031a6edb4f49bbb9fb2ad1e4e9 upstream.

Objcg vectors attached to slab pages to store slab object ownership
information are allocated using gfp flags for the original slab
allocation.  Depending on slab page order and the size of slab objects,
objcg vector can take several pages.

If the original allocation was done with the __GFP_NOFAIL flag, it
triggered a warning in the page allocation code.  Indeed, order > 1 pages
should not been allocated with the __GFP_NOFAIL flag.

Fix this by simply dropping the __GFP_NOFAIL flag when allocating the
objcg vector.  It effectively allows to skip the accounting of a single
slab object under a heavy memory pressure.

An alternative would be to implement the mechanism to fallback to order-0
allocations for accounting metadata, which is also not perfect because it
will increase performance penalty and memory footprint of the kernel
memory accounting under memory pressure.

Link: https://lkml.kernel.org/r/ZUp8ZFGxwmCx4ZFr@P9FQF9L96D.corp.robot.car
Signed-off-by: Roman Gushchin 
Reported-by: Christoph Lameter 
Closes: https://lkml.kernel.org/r/6b42243e-f197-600a-5d22-56bd728a5ad8@gentwo.org
Acked-by: Shakeel Butt 
Cc: Matthew Wilcox 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

mm: fix for negative counter: nr_file_hugepages

2023-11-28T17:20:13+00:00

commit a48d5bdc877b85201e42cef9c2fdf5378164c23a upstream.

While qualifiying the 6.4 release, the following warning was detected in
messages:

vmstat_refresh: nr_file_hugepages -15664

The warning is caused by the incorrect updating of the NR_FILE_THPS
counter in the function split_huge_page_to_list.  The if case is checking
for folio_test_swapbacked, but the else case is missing the check for
folio_test_pmd_mappable.  The other functions that manipulate the counter
like __filemap_add_folio and filemap_unaccount_folio have the
corresponding check.

I have a test case, which reproduces the problem. It can be found here:
  https://github.com/sroeschus/testcase/blob/main/vmstat_refresh/madv.c

The test case reproduces on an XFS filesystem. Running the same test
case on a BTRFS filesystem does not reproduce the problem.

AFAIK version 6.1 until 6.6 are affected by this problem.

[akpm@linux-foundation.org: whitespace fix]
[shr@devkernel.io: test for folio_test_pmd_mappable()]
  Link: https://lkml.kernel.org/r/20231108171517.2436103-1-shr@devkernel.io
Link: https://lkml.kernel.org/r/20231106181918.1091043-1-shr@devkernel.io
Signed-off-by: Stefan Roesch 
Co-debugged-by: Johannes Weiner 
Acked-by: Johannes Weiner 
Reviewed-by: Matthew Wilcox (Oracle) 
Reviewed-by: David Hildenbrand 
Reviewed-by: Yang Shi 
Cc: Rik van Riel 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

parisc: fix mmap_base calculation when stack grows upwards

2023-11-28T17:20:08+00:00

commit 5f74f820f6fc844b95f9e5e406e0a07d97510420 upstream.

Matoro reported various userspace crashes on the parisc platform with kernel
6.6 and bisected it to commit 3033cd430768 ("parisc: Use generic mmap top-down
layout and brk randomization").

That commit switched parisc to use the common infrastructure to calculate
mmap_base, but missed that the mmap_base() function takes care for
architectures where the stack grows downwards only.

Fix the mmap_base() calculation to include the stack-grows-upwards case
and thus fix the userspace crashes on parisc.

Link: https://lkml.kernel.org/r/ZVH2qeS1bG7/1J/l@p100
Fixes: 3033cd430768 ("parisc: Use generic mmap top-down layout and brk randomization")
Signed-off-by: Helge Deller 
Reported-by: matoro 
Tested-by: matoro 
Cc: 	[6.6+]
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

mm/memory_hotplug: use pfn math in place of direct struct page manipulation

2023-11-28T17:20:06+00:00

commit 1640a0ef80f6d572725f5b0330038c18e98ea168 upstream.

When dealing with hugetlb pages, manipulating struct page pointers
directly can get to wrong struct page, since struct page is not guaranteed
to be contiguous on SPARSEMEM without VMEMMAP.  Use pfn calculation to
handle it properly.

Without the fix, a wrong number of page might be skipped. Since skip cannot be
negative, scan_movable_page() will end early and might miss a movable page with
-ENOENT. This might fail offline_pages(). No bug is reported. The fix comes
from code inspection.

Link: https://lkml.kernel.org/r/20230913201248.452081-4-zi.yan@sent.com
Fixes: eeb0efd071d8 ("mm,memory_hotplug: fix scan_movable_pages() for gigantic hugepages")
Signed-off-by: Zi Yan 
Reviewed-by: Muchun Song 
Acked-by: David Hildenbrand 
Cc: Matthew Wilcox (Oracle) 
Cc: Mike Kravetz 
Cc: Mike Rapoport (IBM) 
Cc: Thomas Bogendoerfer 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman