linux.git/mm, branch v6.7-rc2

mm: more ptep_get() conversion

2023-11-15T23:30:09+00:00

Commit c33c794828f2 ("mm: ptep_get() conversion") converted all (non-arch)
call sites to use ptep_get() instead of doing a direct dereference of the
pte.  Full rationale can be found in that commit's log.

Since then, three new call sites have snuck in, which directly dereference
the pte, so let's fix those up.

Unfortunately there is no reliable automated mechanism to catch these; I'm
relying on a combination of Coccinelle (which throws up a lot of false
positives) and some compiler magic to force a compiler error on
dereference (While this approach finds dereferences, it also yields a
non-booting kernel so can't be committed).

Link: https://lkml.kernel.org/r/20231114154945.490401-1-ryan.roberts@arm.com
Signed-off-by: Ryan Roberts 
Cc: Matthew Wilcox (Oracle) 
Signed-off-by: Andrew Morton

parisc: fix mmap_base calculation when stack grows upwards

2023-11-15T23:30:09+00:00

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

mm/damon/core.c: avoid unintentional filtering out of schemes

2023-11-15T23:30:09+00:00

The function '__damos_filter_out()' causes DAMON to always filter out
schemes whose filter type is anon or memcg if its matching value is set
to false.

This commit addresses the issue by ensuring that '__damos_filter_out()'
no longer applies to filters whose type is 'anon' or 'memcg'.

Link: https://lkml.kernel.org/r/1699594629-3816-1-git-send-email-hyeongtak.ji@gmail.com
Fixes: ab9bda001b681 ("mm/damon/core: introduce address range type damos filter")
Signed-off-by: Hyeongtak Ji 
Reviewed-by: SeongJae Park 
Cc: 
Signed-off-by: Andrew Morton

mm: kmem: drop __GFP_NOFAIL when allocating objcg vectors

2023-11-15T23:30:09+00:00

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

mm/damon/sysfs-schemes: handle tried region directory allocation failure

2023-11-15T23:30:09+00:00

DAMON sysfs interface's before_damos_apply callback
(damon_sysfs_before_damos_apply()), which creates the DAMOS tried regions
for each DAMOS action applied region, is not handling the allocation
failure for the sysfs directory data.  As a result, NULL pointer
derefeence is possible.  Fix it by handling the case.

Link: https://lkml.kernel.org/r/20231106233408.51159-4-sj@kernel.org
Fixes: f1d13cacabe1 ("mm/damon/sysfs: implement DAMOS tried regions update command")
Signed-off-by: SeongJae Park 
Cc: 	[6.2+]
Signed-off-by: Andrew Morton

mm/damon/sysfs-schemes: handle tried regions sysfs directory allocation failure

2023-11-15T23:30:09+00:00

DAMOS tried regions sysfs directory allocation function
(damon_sysfs_scheme_regions_alloc()) is not handling the memory allocation
failure.  In the case, the code will dereference NULL pointer.  Handle the
failure to avoid such invalid access.

Link: https://lkml.kernel.org/r/20231106233408.51159-3-sj@kernel.org
Fixes: 9277d0367ba1 ("mm/damon/sysfs-schemes: implement scheme region directory")
Signed-off-by: SeongJae Park 
Cc: 	[6.2+]
Signed-off-by: Andrew Morton

mm/damon/sysfs: check error from damon_sysfs_update_target()

2023-11-15T23:30:09+00:00

Patch series "mm/damon/sysfs: fix unhandled return values".

Some of DAMON sysfs interface code is not handling return values from some
functions.  As a result, confusing user input handling or NULL-dereference
is possible.  Check those properly.


This patch (of 3):

damon_sysfs_update_target() returns error code for failures, but its
caller, damon_sysfs_set_targets() is ignoring that.  The update function
seems making no critical change in case of such failures, but the behavior
will look like DAMON sysfs is silently ignoring or only partially
accepting the user input.  Fix it.

Link: https://lkml.kernel.org/r/20231106233408.51159-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20231106233408.51159-2-sj@kernel.org
Fixes: 19467a950b49 ("mm/damon/sysfs: remove requested targets when online-commit inputs")
Signed-off-by: SeongJae Park 
Cc: 	[5.19+]
Signed-off-by: Andrew Morton

mm: fix for negative counter: nr_file_hugepages

2023-11-15T23:30:09+00:00

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

mm/damon/sysfs: eliminate potential uninitialized variable warning

2023-11-15T23:30:08+00:00

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

Merge tag 'memblock-v6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock

2023-11-08T17:40:13+00:00

Pull memblock update from Mike Rapoport:
 "Report failures when memblock_can_resize is not set.

  Numerous memblock reservations at early boot may exhaust static
  memblock.reserved array and it is unnoticed because most of the
  callers don't check memblock_reserve() return value.

  In this case the system will crash later, but the reason is hard to
  identify.

  Replace return of an error with panic() when memblock.reserved is
  exhausted before it can be resized"

* tag 'memblock-v6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
  memblock: report failures when memblock_can_resize is not set