linux/mm
Zach O'Keefe 9319b64790 mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again
(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: f6789593d5 ("mm/page-writeback.c: fix divide by zero in bdi_dirty_limits()")
Signed-off-by: Zach O'Keefe <zokeefe@google.com>
Cc: Maxim Patlasov <MPatlasov@parallels.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-01-25 23:52:20 -08:00
..
damon mm/damon/vaddr: change asm-generic/mman-common.h to linux/mman.h 2023-12-29 11:58:57 -08:00
kasan kasan: avoid resetting aux_lock 2024-01-12 15:20:45 -08:00
kfence KFENCE: cleanup kfence_guarded_alloc() after CONFIG_SLAB removal 2023-12-05 11:17:58 +01:00
kmsan mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
backing-dev.c writeback: remove redundant checks for root memcg 2023-08-21 13:37:48 -07:00
balloon_compaction.c
bootmem_info.c bootmem: use kmemleak_free_part_phys in put_page_bootmem 2023-10-25 16:47:13 -07:00
cma_debug.c
cma_sysfs.c
cma.c mm: cma: remove unnecessary initialization of ret 2023-12-12 10:57:08 -08:00
cma.h
compaction.c Generic: 2024-01-17 13:03:37 -08:00
debug_page_alloc.c mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
debug_page_ref.c
debug_vm_pgtable.c mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
debug.c mm: update validate_mm() to use vma iterator 2023-06-09 16:25:31 -07:00
dmapool_test.c
dmapool.c mm/mempool/dmapool: remove CONFIG_DEBUG_SLAB ifdefs 2023-12-05 11:17:58 +01:00
early_ioremap.c mm/early_ioremap.c: improve the execution efficiency of early_ioremap_setup() 2023-06-09 16:25:56 -07:00
fadvise.c mm: remove unnecessary pagevec includes 2023-06-23 16:59:31 -07:00
fail_page_alloc.c mm: page_alloc: split out FAIL_PAGE_ALLOC 2023-06-09 16:25:23 -07:00
failslab.c
filemap.c vfs-6.8.netfs 2024-01-19 09:10:23 -08:00
folio-compat.c mm: remove page_add_new_anon_rmap and lru_cache_add_inactive_or_unevictable 2023-12-29 11:58:27 -08:00
gup_test.c Merge mm-hotfixes-stable into mm-stable to pick up depended-upon changes. 2023-06-23 16:58:19 -07:00
gup_test.h
gup.c mm: convert page_try_share_anon_rmap() to folio_try_share_anon_rmap_[pte|pmd]() 2023-12-29 11:58:56 -08:00
highmem.c x86/kexec: use pr_err() instead of kexec_dprintk() when an error occurs 2023-12-29 12:22:28 -08:00
hmm.c mm: enable page walking API to lock vmas during the walk 2023-08-21 13:07:20 -07:00
huge_memory.c Many singleton patches against the MM code. The patch series which 2024-01-09 11:18:47 -08:00
hugetlb_cgroup.c mm, hugetlb: remove HUGETLB_CGROUP_MIN_ORDER 2023-10-18 14:34:17 -07:00
hugetlb_vmemmap.c mm: hugetlb_vmemmap: move mmap lock to vmemmap_remap_range() 2023-12-12 10:57:08 -08:00
hugetlb_vmemmap.h mm: hugetlb_vmemmap: fix reference to nonexistent file 2023-10-25 16:47:14 -07:00
hugetlb.c Many singleton patches against the MM code. The patch series which 2024-01-09 11:18:47 -08:00
hwpoison-inject.c
init-mm.c mm: Deprecate pasid field 2023-12-12 10:11:32 +01:00
internal.h mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
interval_tree.c
io-mapping.c
ioremap.c mm: ioremap: remove unneeded ioremap_allowed and iounmap_allowed 2023-08-18 10:12:36 -07:00
Kconfig IOMMU Updates for Linux v6.8 2024-01-18 15:16:57 -08:00
Kconfig.debug mm/slab: remove CONFIG_SLAB from all Kconfig and Makefile 2023-12-05 11:14:40 +01:00
khugepaged.c header cleanups for 6.8 2024-01-10 16:43:55 -08:00
kmemleak.c kmemleak: avoid RCU stalls when freeing metadata for per-CPU pointers 2023-12-12 10:57:07 -08:00
ksm.c mm: convert page_try_share_anon_rmap() to folio_try_share_anon_rmap_[pte|pmd]() 2023-12-29 11:58:56 -08:00
list_lru.c mm/list_lru.c: remove unused list_lru_from_kmem() 2023-12-20 14:48:11 -08:00
maccess.c
madvise.c mm: return a folio from read_swap_cache_async() 2023-12-29 11:58:32 -08:00
Makefile mm/slab: remove CONFIG_SLAB from all Kconfig and Makefile 2023-12-05 11:14:40 +01:00
mapping_dirty_helpers.c mm: fix clean_record_shared_mapping_range kernel-doc 2023-08-24 16:20:30 -07:00
memblock.c memblock: code readability improvement 2024-01-18 16:46:18 -08:00
memcontrol.c mm: memcontrol: don't throttle dying tasks on memory.high 2024-01-25 23:52:20 -08:00
memfd.c memfd: drop warning for missing exec-related flags 2023-10-04 10:32:22 -07:00
memory_hotplug.c mm/memory_hotplug: fix memmap_on_memory sysfs value retrieval 2024-01-12 15:20:48 -08:00
memory-failure.c fs/hugetlbfs/inode.c: mm/memory-failure.c: fix hugetlbfs hwpoison handling 2024-01-25 23:52:20 -08:00
memory-tiers.c base/node / acpi: Change 'node_hmem_attrs' to 'access_coordinates' 2023-12-22 14:23:13 -08:00
memory.c Many singleton patches against the MM code. The patch series which 2024-01-09 11:18:47 -08:00
mempolicy.c Many singleton patches against the MM code. The patch series which are 2023-11-02 19:38:47 -10:00
mempool.c Many singleton patches against the MM code. The patch series which 2024-01-09 11:18:47 -08:00
memremap.c mm: remove stale example from comment 2023-12-29 11:58:26 -08:00
memtest.c mm: memtest: convert to memtest_report_meminfo() 2023-08-21 13:37:47 -07:00
migrate_device.c mm: convert page_try_share_anon_rmap() to folio_try_share_anon_rmap_[pte|pmd]() 2023-12-29 11:58:56 -08:00
migrate.c Generic: 2024-01-17 13:03:37 -08:00
mincore.c mm: enable page walking API to lock vmas during the walk 2023-08-21 13:07:20 -07:00
mlock.c mm: mlock: avoid folio_within_range() on KSM pages 2023-10-25 16:47:14 -07:00
mm_init.c efi: disable mirror feature during crashkernel 2024-01-12 15:20:47 -08:00
mm_slot.h
mmap_lock.c
mmap.c Many singleton patches against the MM code. The patch series which 2024-01-09 11:18:47 -08:00
mmu_gather.c mm/memory: page_remove_rmap() -> folio_remove_rmap_pte() 2023-12-29 11:58:54 -08:00
mmu_notifier.c mmu_notifiers: rename invalidate_range notifier 2023-08-18 10:12:41 -07:00
mmzone.c zswap: shrink zswap pool based on memory pressure 2023-12-12 10:57:02 -08:00
mprotect.c mm: mprotect: use a folio in change_pte_range() 2023-10-25 16:47:12 -07:00
mremap.c mm: abstract VMA merge and extend into vma_merge_extend() helper 2023-10-18 14:34:18 -07:00
msync.c
nommu.c Many singleton patches against the MM code. The patch series which are 2023-11-02 19:38:47 -10:00
oom_kill.c mm, oom:dump_tasks add rss detailed information printing 2023-12-10 16:51:53 -08:00
page_alloc.c Networking changes for 6.8. 2024-01-11 10:07:29 -08:00
page_counter.c
page_ext.c mm/page_ext: move functions around for minor cleanups to page_ext 2023-08-18 10:12:31 -07:00
page_idle.c
page_io.c zswap: memcontrol: implement zswap writeback disabling 2023-12-29 20:22:11 -08:00
page_isolation.c mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
page_owner.c mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
page_poison.c mm/page_poison: replace kmap_atomic() with kmap_local_page() 2023-12-10 16:51:50 -08:00
page_reporting.c mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
page_reporting.h
page_table_check.c mm: convert page_table_check_pte_set() to page_table_check_ptes_set() 2023-08-24 16:20:18 -07:00
page_vma_mapped.c mm: thp: introduce multi-size THP sysfs interface 2023-12-20 14:48:12 -08:00
page-writeback.c mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again 2024-01-25 23:52:20 -08:00
pagewalk.c mm: pagewalk: assert write mmap lock only for walking the user page tables 2023-12-10 16:51:53 -08:00
percpu-internal.h percpu-internal/pcpu_chunk: re-layout pcpu_chunk structure to reduce false sharing 2023-06-19 16:19:29 -07:00
percpu-km.c
percpu-stats.c
percpu-vm.c
percpu.c mm: Introduce flush_cache_vmap_early() 2023-12-14 00:23:17 -08:00
pgalloc-track.h
pgtable-generic.c mm/pgtable: notes on pte_offset_map[_lock]() 2023-08-18 10:12:25 -07:00
process_vm_access.c mm: fix process_vm_rw page counts 2023-12-10 16:51:39 -08:00
ptdump.c mm: ptdump should use ptep_get_lockless() 2023-06-19 16:19:24 -07:00
readahead.c readahead: avoid multiple marked readahead pages 2024-01-25 23:52:20 -08:00
rmap.c mm/rmap: rename COMPOUND_MAPPED to ENTIRELY_MAPPED 2023-12-29 11:58:56 -08:00
rodata_test.c
secretmem.c mm/secretmem: use a folio in secretmem_fault() 2023-08-21 13:38:02 -07:00
shmem_quota.c shmem: Add default quota limit mount options 2023-08-09 09:15:40 +02:00
shmem.c header cleanups for 6.8 2024-01-10 16:43:55 -08:00
show_mem.c mm, treewide: introduce NR_PAGE_ORDERS 2024-01-08 15:27:15 -08:00
shrinker_debug.c mm: shrinker: convert shrinker_rwsem to mutex 2023-10-04 10:32:26 -07:00
shrinker.c mm: shrinker: use kvzalloc_node() from expand_one_shrinker_info() 2024-01-05 09:58:32 -08:00
shuffle.c
shuffle.h mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
slab_common.c slub: use a folio in __kmalloc_large_node 2024-01-05 10:17:46 -08:00
slab.h mm/slab: move kmalloc() functions from slab_common.c to slub.c 2023-12-06 11:57:21 +01:00
slub.c Many singleton patches against the MM code. The patch series which 2024-01-09 11:18:47 -08:00
sparse-vmemmap.c mm/vmemmap: allow architectures to override how vmemmap optimization works 2023-08-18 10:12:53 -07:00
sparse.c mm/sparsemem: fix race in accessing memory_section->usage 2023-12-29 11:58:43 -08:00
swap_cgroup.c
swap_slots.c
swap_state.c mm: convert swap_cluster_readahead and swap_vma_readahead to return a folio 2023-12-29 11:58:32 -08:00
swap.c mm: remove references to pagevec 2023-06-23 16:59:30 -07:00
swap.h mm: convert swap_cluster_readahead and swap_vma_readahead to return a folio 2023-12-29 11:58:32 -08:00
swapfile.c header cleanups for 6.8 2024-01-10 16:43:55 -08:00
truncate.c fs: convert error_remove_page to error_remove_folio 2023-12-10 16:51:42 -08:00
usercopy.c
userfaultfd.c userfaultfd: avoid huge_zero_page in UFFDIO_MOVE 2024-01-12 15:20:49 -08:00
util.c mm/util: use kmap_local_page() in memcmp_pages() 2023-12-10 16:51:49 -08:00
vmalloc.c mm/vmalloc: fix the unchecked dereference warning in vread_iter() 2023-11-01 12:38:35 -07:00
vmpressure.c eventfd: simplify eventfd_signal() 2023-11-28 14:08:38 +01:00
vmscan.c Many singleton patches against the MM code. The patch series which 2024-01-09 11:18:47 -08:00
vmstat.c mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
workingset.c mm: ratelimit stat flush from workingset shrinker 2024-01-05 10:17:45 -08:00
z3fold.c mm/z3fold: remove obsolete comment for struct z3fold_pool 2023-08-21 13:37:51 -07:00
zbud.c mm: zswap: remove shrink from zpool interface 2023-06-19 16:19:27 -07:00
zpool.c mm: zswap: remove shrink from zpool interface 2023-06-19 16:19:27 -07:00
zsmalloc.c mm: zsmalloc: return -ENOSPC rather than -EINVAL in zs_malloc while size is too large 2024-01-05 10:17:47 -08:00
zswap.c zswap: memcontrol: implement zswap writeback disabling 2023-12-29 20:22:11 -08:00