mirror_ubuntu-kernels/mm
Florian Schmidt 6b0ba2abbe memcg v1: provide read access to memory.pressure_level
cgroups v1 has a unique way of setting up memory pressure notifications:
the user opens "memory.pressure_level" of the cgroup they want to monitor
for pressure, then open "cgroup.event_control" and write the fd (among
other things) to that file.  memory.pressure_level has no other use,
specifically it does not support any read or write operations. 
Consequently, no handlers are provided, and cgroup_file_mode() sets the
permissions to 000.  However, to actually use the mechanism, the
subscribing user must have read access to the file and open the fd for
reading, see memcg_write_event_control().

This is all fine as long as the subscribing process runs as root and is
otherwise unconfined by further restrictions.  However, if you add strict
access controls such as selinux, the permission bits will be enforced, and
opening memory.pressure_level for reading will fail, preventing the
process from subscribing, even as root.

To work around this issue, introduce a dummy read handler.  When
memory.pressure_level is created, cgroup_file_mode() will notice the
existence of a handler, and therefore add read permissions to the file.

Link: https://lkml.kernel.org/r/20230404105900.2005-1-flosch@nutanix.com
Signed-off-by: Florian Schmidt <flosch@nutanix.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-04-18 16:29:52 -07:00
..
damon mm/damon/sysfs: make more kobj_type structures constant 2023-04-05 19:42:59 -07:00
kasan kasan: suppress recursive reports for HW_TAGS 2023-04-05 19:42:43 -07:00
kfence mm: kfence: improve the performance of __kfence_alloc() and __kfence_free() 2023-04-18 16:29:49 -07:00
kmsan kmsan: fix a stale comment in kmsan_save_stack_with_flags() 2023-04-18 16:29:47 -07:00
backing-dev.c writeback, cgroup: fix null-ptr-deref write in bdi_split_work_to_wbs 2023-04-16 10:41:26 -07:00
balloon_compaction.c mm: Convert all PageMovable users to movable_operations 2022-08-02 12:34:03 -04:00
bootmem_info.c bootmem: remove the vmemmap pages from kmemleak in put_page_bootmem 2022-08-28 14:02:45 -07:00
cma_debug.c mm/cma_debug: show complete cma name in debugfs directories 2022-09-11 20:25:50 -07:00
cma_sysfs.c mm: cma: make kobj_type structure constant 2023-03-28 16:20:06 -07:00
cma.c mm: move most of core MM initialization to mm/mm_init.c 2023-04-05 19:42:52 -07:00
cma.h mm/cma: provide option to opt out from exposing pages on activation failure 2022-03-22 15:57:09 -07:00
compaction.c mm: compaction: fix the possible deadlock when isolating hugetlb pages 2023-04-05 19:42:50 -07:00
debug_page_ref.c
debug_vm_pgtable.c mm, treewide: redefine MAX_ORDER sanely 2023-04-05 19:42:46 -07:00
debug.c mm/debug: use %pGt to display page_type in dump_page() 2023-03-28 16:20:09 -07:00
dmapool_test.c dmapool: add alloc/free performance test 2023-04-05 19:42:38 -07:00
dmapool.c dmapool: create/destroy cleanup 2023-04-05 19:42:41 -07:00
early_ioremap.c mm/early_ioremap: declare early_memremap_pgprot_adjust() 2022-03-22 15:57:11 -07:00
fadvise.c mm: support POSIX_FADV_NOREUSE 2023-01-18 17:12:57 -08:00
failslab.c mm: fix unexpected changes to {failslab|fail_page_alloc}.attr 2022-11-22 18:50:44 -08:00
filemap.c mm: return an ERR_PTR from __filemap_get_folio 2023-04-05 19:42:42 -07:00
folio-compat.c mm: return an ERR_PTR from __filemap_get_folio 2023-04-05 19:42:42 -07:00
frontswap.c frontswap: don't call ->init if no ops are registered 2022-09-26 12:14:34 -07:00
gup_test.c mm/gup_test: free memory allocated via kvcalloc() using kvfree() 2022-12-15 16:37:48 -08:00
gup_test.h mm/gup_test: start/stop/read functionality for PIN LONGTERM test 2022-11-08 17:37:15 -08:00
gup.c mm/gup.c: fix typo in comments 2023-03-28 16:20:14 -07:00
highmem.c highmem: fix kmap_to_page() for kmap_local_page() addresses 2022-10-12 18:51:51 -07:00
hmm.c mm/hugetlb: make walk_hugetlb_range() safe to pmd unshare 2023-01-18 17:12:39 -08:00
huge_memory.c sync mm-stable with mm-hotfixes-stable to pick up depended-upon upstream changes 2023-04-16 12:31:58 -07:00
hugetlb_cgroup.c mm/hugetlb: increase use of folios in alloc_huge_page() 2023-02-13 15:54:27 -08:00
hugetlb_vmemmap.c mm: prefer xxx_page() alloc/free functions for order-0 pages 2023-03-28 16:20:16 -07:00
hugetlb_vmemmap.h mm: hugetlb_vmemmap: improve hugetlb_vmemmap code readability 2022-08-08 18:06:43 -07:00
hugetlb.c hugetlb: remove PageHeadHuge() 2023-04-18 16:29:46 -07:00
hwpoison-inject.c mm/hwpoison: add __init/__exit annotations to module init/exit funcs 2022-10-03 14:03:05 -07:00
init-mm.c mm: add per-VMA lock and helper functions to control it 2023-04-05 20:02:57 -07:00
internal.h mm: move free_area_empty() to mm/internal.h 2023-04-18 16:29:47 -07:00
interval_tree.c
io-mapping.c
ioremap.c mm: ioremap: Add ioremap/iounmap_allowed() 2022-06-27 12:22:31 +01:00
Kconfig mm: introduce CONFIG_PER_VMA_LOCK 2023-04-05 20:02:56 -07:00
Kconfig.debug kmemleak-test: fix kmemleak_test.c build logic 2023-04-18 16:29:47 -07:00
khugepaged.c mm/khugepaged: maintain page cache uptodate flag 2023-04-18 16:29:52 -07:00
kmemleak.c lib/stackdepot, mm: rename stack_depot_want_early_init 2023-02-16 20:43:49 -08:00
ksm.c mm: add tracepoints to ksm 2023-03-28 16:20:08 -07:00
list_lru.c mm: kmem: make mem_cgroup_from_obj() vmalloc()-safe 2022-06-16 19:48:31 -07:00
maccess.c maccess: Fix writing offset in case of fault in strncpy_from_kernel_nofault() 2022-11-11 11:44:46 -08:00
madvise.c - Daniel Verkamp has contributed a memfd series ("mm/memfd: add 2023-02-23 17:09:35 -08:00
Makefile dmapool: add alloc/free performance test 2023-04-05 19:42:38 -07:00
mapping_dirty_helpers.c mm/mmu_notifier: remove unused mmu_notifier_range_update_to_read_only export 2023-02-02 22:32:54 -08:00
memblock.c mm: avoid passing 0 to __ffs() 2023-04-18 16:29:42 -07:00
memcontrol.c memcg v1: provide read access to memory.pressure_level 2023-04-18 16:29:52 -07:00
memfd.c mm/memfd: add write seals when apply SEAL_EXEC to executable memfd 2023-01-18 17:12:37 -08:00
memory_hotplug.c mm: avoid passing 0 to __ffs() 2023-04-18 16:29:42 -07:00
memory-failure.c mm: memory-failure: directly use IS_ENABLED(CONFIG_HWPOISON_INJECT) 2023-03-28 16:20:17 -07:00
memory-tiers.c memory tier: release the new_memtier in find_create_memory_tier() 2023-02-09 16:51:40 -08:00
memory.c sync mm-stable with mm-hotfixes-stable to pick up depended-upon upstream changes 2023-04-16 12:31:58 -07:00
mempolicy.c mm/mempolicy: fix use-after-free of VMA iterator 2023-04-16 10:41:25 -07:00
mempool.c mempool: do not use ksize() for poisoning 2022-11-30 15:58:41 -08:00
memremap.c mm/memremap.c: fix outdated comment in devm_memremap_pages 2023-02-09 16:51:46 -08:00
memtest.c mm/memtest: add results of early memtest to /proc/meminfo 2023-04-05 19:42:55 -07:00
migrate_device.c mm: change to return bool for isolate_lru_page() 2023-02-20 12:46:17 -08:00
migrate.c mm/migrate: drop pte_mkhuge() in remove_migration_pte() 2023-03-28 16:20:11 -07:00
mincore.c mm: return an ERR_PTR from __filemap_get_folio 2023-04-05 19:42:42 -07:00
mlock.c mm: introduce vm_flags_reset_once to replace WRITE_ONCE vm_flags updates 2023-02-09 16:51:41 -08:00
mm_init.c mm: make arch_has_descending_max_zone_pfns() static 2023-04-18 16:29:42 -07:00
mm_slot.h mm: introduce common struct mm_slot 2022-10-03 14:02:43 -07:00
mmap_lock.c mm: mmap_lock: fix disabling preemption directly 2021-07-23 17:43:28 -07:00
mmap.c sync mm-stable with mm-hotfixes-stable to pick up depended-upon upstream changes 2023-04-18 14:53:49 -07:00
mmu_gather.c mm: prefer xxx_page() alloc/free functions for order-0 pages 2023-03-28 16:20:16 -07:00
mmu_notifier.c mm/mmu_notifier: remove unused mmu_notifier_range_update_to_read_only export 2023-02-02 22:32:54 -08:00
mmzone.c mm: multi-gen LRU: groundwork 2022-09-26 19:46:09 -07:00
mprotect.c sync mm-stable with mm-hotfixes-stable to pick up depended-upon upstream changes 2023-04-16 12:31:58 -07:00
mremap.c mm/mremap: write-lock VMA while remapping it to a new address range 2023-04-05 20:02:58 -07:00
msync.c mm/msync: use vma_find() instead of vma linked list 2022-09-26 19:46:25 -07:00
nommu.c mm: vmalloc: convert vread() to vread_iter() 2023-04-05 19:42:57 -07:00
oom_kill.c mm/mmu_notifier: remove unused mmu_notifier_range_update_to_read_only export 2023-02-02 22:32:54 -08:00
page_alloc.c sync mm-stable with mm-hotfixes-stable to pick up depended-upon upstream changes 2023-04-18 14:53:49 -07:00
page_counter.c mm: page_counter: remove unneeded atomic ops for low/min 2022-09-11 20:26:01 -07:00
page_ext.c mm/page_ext: init page_ext early if there are no deferred struct pages 2023-02-02 22:33:22 -08:00
page_idle.c mm: page_idle: convert page idle to use a folio 2023-01-18 17:12:52 -08:00
page_io.c - Daniel Verkamp has contributed a memfd series ("mm/memfd: add 2023-02-23 17:09:35 -08:00
page_isolation.c mm, treewide: redefine MAX_ORDER sanely 2023-04-05 19:42:46 -07:00
page_owner.c mm, treewide: redefine MAX_ORDER sanely 2023-04-05 19:42:46 -07:00
page_poison.c
page_reporting.c mm, treewide: redefine MAX_ORDER sanely 2023-04-05 19:42:46 -07:00
page_reporting.h mm/page_reporting: export reporting order as module parameter 2021-06-29 10:53:47 -07:00
page_table_check.c mm/page_ext: do not allocate space for page_ext->flags if not needed 2023-02-02 22:33:11 -08:00
page_vma_mapped.c mm/hugetlb: introduce hugetlb_walk() 2023-01-18 17:12:39 -08:00
page-writeback.c mm,jfs: move write_one_page/folio_write_one to jfs 2023-03-28 16:20:14 -07:00
pagewalk.c mm/hugetlb: introduce hugetlb_walk() 2023-01-18 17:12:39 -08:00
percpu-internal.h mm: percpu: fix incorrect size in pcpu_obj_full_size() 2023-02-16 20:43:55 -08:00
percpu-km.c percpu: flush tlb in pcpu_reclaim_populated() 2021-07-04 18:30:17 +00:00
percpu-stats.c mm: use vmalloc_array and vcalloc for array allocations 2022-03-08 09:30:46 -05:00
percpu-vm.c percpu: flush tlb in pcpu_reclaim_populated() 2021-07-04 18:30:17 +00:00
percpu.c mm: memcontrol: rename memcg_kmem_enabled() 2023-02-16 20:43:56 -08:00
pgalloc-track.h
pgtable-generic.c mm: add PTE pointer parameter to flush_tlb_fix_spurious_fault() 2023-03-28 16:20:12 -07:00
process_vm_access.c use less confusing names for iov_iter direction initializers 2022-11-25 13:01:55 -05:00
ptdump.c mm: pagewalk: Fix race between unmap and page walker 2022-09-03 10:13:13 -07:00
readahead.c readahead: convert readahead_expand() to use a folio 2023-02-02 22:33:21 -08:00
rmap.c mm/khugepaged: write-lock VMA while collapsing a huge page 2023-04-05 20:02:58 -07:00
rodata_test.c mm/rodata_test: use PAGE_ALIGNED() helper 2022-10-03 14:03:05 -07:00
secretmem.c - Daniel Verkamp has contributed a memfd series ("mm/memfd: add 2023-02-23 17:09:35 -08:00
shmem.c mm: userfaultfd: combine 'mode' and 'wp_copy' arguments 2023-04-05 19:42:48 -07:00
shrinker_debug.c mm: shrinkers: convert shrinker_rwsem to mutex 2023-03-28 16:20:17 -07:00
shuffle.c mm/shuffle: convert module_param_call to module_param_cb 2022-10-03 14:03:07 -07:00
shuffle.h mm, treewide: redefine MAX_ORDER sanely 2023-04-05 19:42:46 -07:00
slab_common.c mm/kasan: simplify and refine kasan_cache code 2023-01-18 17:12:55 -08:00
slab.c mm, treewide: redefine MAX_ORDER sanely 2023-04-05 19:42:46 -07:00
slab.h mm: move kmem_cache_init() declaration to mm/slab.h 2023-04-05 19:42:54 -07:00
slob.c Merge branch 'slab/for-6.1/kmalloc_size_roundup' into slab/for-next 2022-09-29 11:30:55 +02:00
slub.c mm, treewide: redefine MAX_ORDER sanely 2023-04-05 19:42:46 -07:00
sparse-vmemmap.c mm/sparse-vmemmap: generalise vmemmap_populate_hugepages() 2022-12-11 18:12:12 -08:00
sparse.c mm/sparse: fix "unused function 'pgdat_to_phys'" warning 2023-02-02 22:33:29 -08:00
swap_cgroup.c mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled 2022-10-03 14:03:36 -07:00
swap_slots.c mm/swap: convert put_swap_page() to put_swap_folio() 2022-10-03 14:02:46 -07:00
swap_state.c mm: return an ERR_PTR from __filemap_get_folio 2023-04-05 19:42:42 -07:00
swap.c mm: swap: fix performance regression on sparsetruncate-tiny 2023-04-16 10:41:24 -07:00
swap.h mm: remove the __swap_writepage return value 2023-02-02 22:33:33 -08:00
swapfile.c sync mm-stable with mm-hotfixes-stable to pick up depended-upon upstream changes 2023-04-16 12:31:58 -07:00
truncate.c mm: return an ERR_PTR from __filemap_get_folio 2023-04-05 19:42:42 -07:00
usercopy.c mm: use kstrtobool() instead of strtobool() 2022-11-30 15:58:45 -08:00
userfaultfd.c mm: userfaultfd: add UFFDIO_CONTINUE_MODE_WP to install WP PTEs 2023-04-05 19:42:48 -07:00
util.c mm: fix typo in __vm_enough_memory warning 2023-02-13 15:54:33 -08:00
vmalloc.c mm: vmalloc: rename addr_to_vb_xarray() function 2023-04-18 16:29:48 -07:00
vmpressure.c mm/vmpressure: fix data-race with memcg->socket_pressure 2021-11-06 13:30:40 -07:00
vmscan.c vmscan: memcg: sleep when flushing stats during reclaim 2023-04-18 16:29:50 -07:00
vmstat.c mm: introduce per-VMA lock statistics 2023-04-05 20:03:01 -07:00
workingset.c workingset: memcg: sleep when flushing stats in workingset_refault() 2023-04-18 16:29:50 -07:00
z3fold.c mm: remove PageMovable export 2023-01-18 17:12:57 -08:00
zbud.c zpool: clean out dead code 2022-12-11 18:12:10 -08:00
zpool.c zpool: clean out dead code 2022-12-11 18:12:10 -08:00
zsmalloc.c zsmalloc: reset compaction source zspage pointer after putback_zspage() 2023-04-18 16:29:42 -07:00
zswap.c mm/zswap: delay the initialization of zswap 2023-04-18 16:29:48 -07:00