linux-stable.git/mm, branch v6.7.6

blk-wbt: Fix detection of dirty-throttled tasks

2024-02-23T08:51:56+00:00

commit f814bdda774c183b0cc15ec8f3b6e7c6f4527ba5 upstream.

The detection of dirty-throttled tasks in blk-wbt has been subtly broken
since its beginning in 2016. Namely if we are doing cgroup writeback and
the throttled task is not in the root cgroup, balance_dirty_pages() will
set dirty_sleep for the non-root bdi_writeback structure. However
blk-wbt checks dirty_sleep only in the root cgroup bdi_writeback
structure. Thus detection of recently throttled tasks is not working in
this case (we noticed this when we switched to cgroup v2 and suddently
writeback was slow).

Since blk-wbt has no easy way to get to proper bdi_writeback and
furthermore its intention has always been to work on the whole device
rather than on individual cgroups, just move the dirty_sleep timestamp
from bdi_writeback to backing_dev_info. That fixes the checking for
recently throttled task and saves memory for everybody as a bonus.

CC: stable@vger.kernel.org
Fixes: b57d74aff9ab ("writeback: track if we're sleeping on progress in balance_dirty_pages()")
Signed-off-by: Jan Kara 
Link: https://lore.kernel.org/r/20240123175826.21452-1-jack@suse.cz
[axboe: fixup indentation errors]
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

mm/damon/sysfs-schemes: fix wrong DAMOS tried regions update timeout setup

2024-02-23T08:51:55+00:00

commit b9e4bc1046d20e0623a80660ef8627448056f817 upstream.

DAMON sysfs interface's update_schemes_tried_regions command has a timeout
of two apply intervals of the DAMOS scheme.  Having zero value DAMOS
scheme apply interval means it will use the aggregation interval as the
value.  However, the timeout setup logic is mistakenly using the sampling
interval insted of the aggregartion interval for the case.  This could
cause earlier-than-expected timeout of the command.  Fix it.

Link: https://lkml.kernel.org/r/20240202191956.88791-1-sj@kernel.org
Fixes: 7d6fa31a2fd7 ("mm/damon/sysfs-schemes: add timeout for update_schemes_tried_regions")
Signed-off-by: SeongJae Park 
Cc:  # 6.7.x
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again

2024-02-23T08:51:29+00:00

commit 9319b647902cbd5cc884ac08a8a6d54ce111fc78 upstream.

(struct dirty_throttle_control *)->thresh is an unsigned long, but is
passed as the u32 divisor argument to div_u64().  On architectures where
unsigned long is 64 bytes, the argument will be implicitly truncated.

Use div64_u64() instead of div_u64() so that the value used in the "is
this a safe division" check is the same as the divisor.

Also, remove redundant cast of the numerator to u64, as that should happen
implicitly.

This would be difficult to exploit in memcg domain, given the ratio-based
arithmetic domain_drity_limits() uses, but is much easier in global
writeback domain with a BDI_CAP_STRICTLIMIT-backing device, using e.g.
vm.dirty_bytes=(1<<32)*PAGE_SIZE so that dtc->thresh == (1<<32)

Link: https://lkml.kernel.org/r/20240118181954.1415197-1-zokeefe@google.com
Fixes: f6789593d5ce ("mm/page-writeback.c: fix divide by zero in bdi_dirty_limits()")
Signed-off-by: Zach O'Keefe 
Cc: Maxim Patlasov 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

fs/hugetlbfs/inode.c: mm/memory-failure.c: fix hugetlbfs hwpoison handling

2024-02-23T08:51:29+00:00

commit 19d3e221807772f8443e565234a6fdc5a2b09d26 upstream.

has_extra_refcount() makes the assumption that the page cache adds a ref
count of 1 and subtracts this in the extra_pins case.  Commit a08c7193e4f1
(mm/filemap: remove hugetlb special casing in filemap.c) modifies
__filemap_add_folio() by calling folio_ref_add(folio, nr); for all cases
(including hugtetlb) where nr is the number of pages in the folio.  We
should adjust the number of references coming from the page cache by
subtracing the number of pages rather than 1.

In hugetlbfs_read_iter(), folio_test_has_hwpoisoned() is testing the wrong
flag as, in the hugetlb case, memory-failure code calls
folio_test_set_hwpoison() to indicate poison.  folio_test_hwpoison() is
the correct function to test for that flag.

After these fixes, the hugetlb hwpoison read selftest passes all cases.

Link: https://lkml.kernel.org/r/20240112180840.367006-1-sidhartha.kumar@oracle.com
Fixes: a08c7193e4f1 ("mm/filemap: remove hugetlb special casing in filemap.c")
Signed-off-by: Sidhartha Kumar 
Closes: https://lore.kernel.org/linux-mm/20230713001833.3778937-1-jiaqiyan@google.com/T/#m8e1469119e5b831bbd05d495f96b842e4a1c5519
Reported-by: Muhammad Usama Anjum 
Tested-by: Muhammad Usama Anjum 
Acked-by: Miaohe Lin 
Acked-by: Muchun Song 
Cc: James Houghton 
Cc: Jiaqi Yan 
Cc: Matthew Wilcox (Oracle) 
Cc: Naoya Horiguchi 
Cc: 	[6.7+]
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

userfaultfd: fix mmap_changing checking in mfill_atomic_hugetlb

2024-02-23T08:51:28+00:00

commit 67695f18d55924b2013534ef3bdc363bc9e14605 upstream.

In mfill_atomic_hugetlb(), mmap_changing isn't being checked
again if we drop mmap_lock and reacquire it. When the lock is not held,
mmap_changing could have been incremented. This is also inconsistent
with the behavior in mfill_atomic().

Link: https://lkml.kernel.org/r/20240117223729.1444522-1-lokeshgidra@google.com
Fixes: df2cc96e77011 ("userfaultfd: prevent non-cooperative events vs mcopy_atomic races")
Signed-off-by: Lokesh Gidra 
Cc: Andrea Arcangeli 
Cc: Mike Rapoport 
Cc: Axel Rasmussen 
Cc: Brian Geffon 
Cc: David Hildenbrand 
Cc: Jann Horn 
Cc: Kalesh Singh 
Cc: Matthew Wilcox (Oracle) 
Cc: Nicolas Geoffray 
Cc: Peter Xu 
Cc: Suren Baghdasaryan 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

mm: thp_get_unmapped_area must honour topdown preference

2024-02-23T08:51:28+00:00

commit 96204e15310c218fd9355bdcacd02fed1d18070e upstream.

The addition of commit efa7df3e3bb5 ("mm: align larger anonymous mappings
on THP boundaries") caused the "virtual_address_range" mm selftest to
start failing on arm64.  Let's fix that regression.

There were 2 visible problems when running the test; 1) it takes much
longer to execute, and 2) the test fails.  Both are related:

The (first part of the) test allocates as many 1GB anonymous blocks as it
can in the low 256TB of address space, passing NULL as the addr hint to
mmap.  Before the faulty patch, all allocations were abutted and contained
in a single, merged VMA.  However, after this patch, each allocation is in
its own VMA, and there is a 2M gap between each VMA.  This causes the 2
problems in the test: 1) mmap becomes MUCH slower because there are so
many VMAs to check to find a new 1G gap.  2) mmap fails once it hits the
VMA limit (/proc/sys/vm/max_map_count).  Hitting this limit then causes a
subsequent calloc() to fail, which causes the test to fail.

The problem is that arm64 (unlike x86) selects
ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT.  But __thp_get_unmapped_area()
allocates len+2M then always aligns to the bottom of the discovered gap.
That causes the 2M hole.

Fix this by detecting cases where we can still achive the alignment goal
when moved to the top of the allocated area, if configured to prefer
top-down allocation.

While we are at it, fix thp_get_unmapped_area's use of pgoff, which should
always be zero for anonymous mappings.  Prior to the faulty change, while
it was possible for user space to pass in pgoff!=0, the old
mm->get_unmapped_area() handler would not use it.  thp_get_unmapped_area()
does use it, so let's explicitly zero it before calling the handler.  This
should also be the correct behavior for arches that define their own
get_unmapped_area() handler.

Link: https://lkml.kernel.org/r/20240123171420.3970220-1-ryan.roberts@arm.com
Fixes: efa7df3e3bb5 ("mm: align larger anonymous mappings on THP boundaries")
Closes: https://lore.kernel.org/linux-mm/1e8f5ac7-54ce-433a-ae53-81522b2320e1@arm.com/
Signed-off-by: Ryan Roberts 
Reviewed-by: Yang Shi 
Cc: Matthew Wilcox (Oracle) 
Cc: Rik van Riel 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

mm/memory: Use exception ip to search exception tables

2024-02-23T08:51:28+00:00

[ Upstream commit 8fa5070833886268e4fb646daaca99f725b378e9 ]

On architectures with delay slot, instruction_pointer() may differ
from where exception was triggered.

Use exception_ip we just introduced to search exception tables to
get rid of the problem.

Fixes: 4bce37a68ff8 ("mips/mm: Convert to using lock_mm_and_find_vma()")
Reported-by: Xi Ruoyao 
Link: https://lore.kernel.org/r/75e9fd7b08562ad9b456a5bdaacb7cc220311cc9.camel@xry111.site/
Suggested-by: Linus Torvalds 
Signed-off-by: Jiaxun Yang 
Signed-off-by: Thomas Bogendoerfer 
Signed-off-by: Sasha Levin

mm: huge_memory: don't force huge page alignment on 32 bit

2024-02-23T08:51:21+00:00

commit 4ef9ad19e17676b9ef071309bc62020e2373705d upstream.

commit efa7df3e3bb5 ("mm: align larger anonymous mappings on THP
boundaries") caused two issues [1] [2] reported on 32 bit system or compat
userspace.

It doesn't make too much sense to force huge page alignment on 32 bit
system due to the constrained virtual address space.

[1] https://lore.kernel.org/linux-mm/d0a136a0-4a31-46bc-adf4-2db109a61672@kernel.org/
[2] https://lore.kernel.org/linux-mm/CAJuCfpHXLdQy1a2B6xN2d7quTYwg2OoZseYPZTRpU0eHHKD-sQ@mail.gmail.com/

Link: https://lkml.kernel.org/r/20240118180505.2914778-1-shy828301@gmail.com
Fixes: efa7df3e3bb5 ("mm: align larger anonymous mappings on THP boundaries")
Signed-off-by: Yang Shi 
Reported-by: Jiri Slaby 
Reported-by: Suren Baghdasaryan 
Tested-by: Jiri Slaby 
Tested-by: Suren Baghdasaryan 
Reviewed-by: Matthew Wilcox (Oracle) 
Cc: Rik van Riel 
Cc: Christopher Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

mm: Introduce flush_cache_vmap_early()

2024-02-16T18:14:25+00:00

[ Upstream commit 7a92fc8b4d20680e4c20289a670d8fca2d1f2c1b ]

The pcpu setup when using the page allocator sets up a new vmalloc
mapping very early in the boot process, so early that it cannot use the
flush_cache_vmap() function which may depend on structures not yet
initialized (for example in riscv, we currently send an IPI to flush
other cpus TLB).

But on some architectures, we must call flush_cache_vmap(): for example,
in riscv, some uarchs can cache invalid TLB entries so we need to flush
the new established mapping to avoid taking an exception.

So fix this by introducing a new function flush_cache_vmap_early() which
is called right after setting the new page table entry and before
accessing this new mapping. This new function implements a local flush
tlb on riscv and is no-op for other architectures (same as today).

Signed-off-by: Alexandre Ghiti 
Acked-by: Geert Uytterhoeven 
Signed-off-by: Dennis Zhou 
Stable-dep-of: d9807d60c145 ("riscv: mm: execute local TLB flush after populating vmemmap")
Signed-off-by: Sasha Levin

memblock: fix crash when reserved memory is not added to memory

2024-02-01T00:21:18+00:00

[ Upstream commit 6a9531c3a88096a26cf3ac582f7ec44f94a7dcb2 ]

After commit 61167ad5fecd ("mm: pass nid to reserve_bootmem_region()")
nid of a reserved region is used by init_reserved_page() (with
CONFIG_DEFERRED_STRUCT_PAGE_INIT=y) to access node strucure.
In many cases the nid of the reserved memory is not set and this causes
a crash.

When the nid of a reserved region is not set, fall back to
early_pfn_to_nid(), so that nid of the first_online_node will be passed
to init_reserved_page().

Fixes: 61167ad5fecd ("mm: pass nid to reserve_bootmem_region()")
Signed-off-by: Yajun Deng 
Link: https://lore.kernel.org/r/20240118061853.2652295-1-yajun.deng@linux.dev
[rppt: massaged the commit message]
Signed-off-by: Mike Rapoport (IBM) 
Signed-off-by: Sasha Levin