linux-bl808/mm
Lang Yu c10a0f877f mm/kmemleak: avoid scanning potential huge holes
When using devm_request_free_mem_region() and devm_memremap_pages() to
add ZONE_DEVICE memory, if requested free mem region's end pfn were
huge(e.g., 0x400000000), the node_end_pfn() will be also huge (see
move_pfn_range_to_zone()).  Thus it creates a huge hole between
node_start_pfn() and node_end_pfn().

We found on some AMD APUs, amdkfd requested such a free mem region and
created a huge hole.  In such a case, following code snippet was just
doing busy test_bit() looping on the huge hole.

  for (pfn = start_pfn; pfn < end_pfn; pfn++) {
	struct page *page = pfn_to_online_page(pfn);
		if (!page)
			continue;
	...
  }

So we got a soft lockup:

  watchdog: BUG: soft lockup - CPU#6 stuck for 26s! [bash:1221]
  CPU: 6 PID: 1221 Comm: bash Not tainted 5.15.0-custom #1
  RIP: 0010:pfn_to_online_page+0x5/0xd0
  Call Trace:
    ? kmemleak_scan+0x16a/0x440
    kmemleak_write+0x306/0x3a0
    ? common_file_perm+0x72/0x170
    full_proxy_write+0x5c/0x90
    vfs_write+0xb9/0x260
    ksys_write+0x67/0xe0
    __x64_sys_write+0x1a/0x20
    do_syscall_64+0x3b/0xc0
    entry_SYSCALL_64_after_hwframe+0x44/0xae

I did some tests with the patch.

(1) amdgpu module unloaded

before the patch:

  real    0m0.976s
  user    0m0.000s
  sys     0m0.968s

after the patch:

  real    0m0.981s
  user    0m0.000s
  sys     0m0.973s

(2) amdgpu module loaded

before the patch:

  real    0m35.365s
  user    0m0.000s
  sys     0m35.354s

after the patch:

  real    0m1.049s
  user    0m0.000s
  sys     0m1.042s

Link: https://lkml.kernel.org/r/20211108140029.721144-1-lang.yu@amd.com
Signed-off-by: Lang Yu <lang.yu@amd.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-02-04 09:25:05 -08:00
..
damon
kasan lib/stackdepot: always do filter_irq_stacks() in stack_depot_save() 2022-01-22 08:33:38 +02:00
kfence
backing-dev.c
balloon_compaction.c
bootmem_info.c
cma.c
cma.h
cma_debug.c
cma_sysfs.c
compaction.c
debug.c
debug_page_ref.c
debug_vm_pgtable.c mm/debug_vm_pgtable: remove pte entry from the page table 2022-02-04 09:25:04 -08:00
dmapool.c
early_ioremap.c
fadvise.c
failslab.c
filemap.c Merge branch 'akpm' (patches from Andrew) 2022-01-22 11:28:23 +02:00
folio-compat.c
frontswap.c frontswap: remove support for multiple ops 2022-01-22 08:33:38 +02:00
gup.c Revert "mm/gup: small refactoring: simplify try_grab_page()" 2022-02-03 06:51:42 -08:00
gup_test.c
gup_test.h
highmem.c
hmm.c
huge_memory.c
hugetlb.c
hugetlb_cgroup.c
hugetlb_vmemmap.c
hugetlb_vmemmap.h
hwpoison-inject.c
init-mm.c
internal.h
interval_tree.c
io-mapping.c
ioremap.c
Kconfig mm: hide the FRONTSWAP Kconfig symbol 2022-01-22 08:33:38 +02:00
Kconfig.debug
khugepaged.c mm/page_table_check: check entries at pmd levels 2022-02-04 09:25:04 -08:00
kmemleak.c mm/kmemleak: avoid scanning potential huge holes 2022-02-04 09:25:05 -08:00
ksm.c
list_lru.c
maccess.c
madvise.c
Makefile mm: remove cleancache 2022-01-22 08:33:38 +02:00
mapping_dirty_helpers.c
memblock.c
memcontrol.c
memfd.c
memory-failure.c memory-failure: fetch compound_head after pgmap_pfn_valid() 2022-01-30 09:56:58 +02:00
memory.c Merge branch 'akpm' (patches from Andrew) 2022-01-20 10:41:01 +02:00
memory_hotplug.c
mempolicy.c
mempool.c
memremap.c
memtest.c
migrate.c mm/migrate.c: rework migration_entry_wait() to not take a pageref 2022-01-22 08:33:34 +02:00
mincore.c
mlock.c
mm_init.c
mmap.c
mmap_lock.c
mmu_gather.c
mmu_notifier.c
mmzone.c
mprotect.c
mremap.c
msync.c
nommu.c
oom_kill.c
page-writeback.c
page_alloc.c Merge branch 'akpm' (patches from Andrew) 2022-01-20 10:41:01 +02:00
page_counter.c
page_ext.c
page_idle.c
page_io.c delayacct: support swapin delay accounting for swapping without blkio 2022-01-20 08:52:55 +02:00
page_isolation.c Revert "mm/page_isolation: unset migratetype directly for non Buddy page" 2022-02-04 09:25:04 -08:00
page_owner.c lib/stackdepot: allow optional init and stack_table allocation by kvmalloc() 2022-01-22 08:33:37 +02:00
page_poison.c
page_reporting.c
page_reporting.h
page_table_check.c mm/page_table_check: check entries at pmd levels 2022-02-04 09:25:04 -08:00
page_vma_mapped.c
pagewalk.c
percpu-internal.h
percpu-km.c
percpu-stats.c
percpu-vm.c
percpu.c bitmap patches for 5.17-rc1 2022-01-23 06:20:44 +02:00
pgalloc-track.h
pgtable-generic.c
process_vm_access.c
ptdump.c
readahead.c
rmap.c
rodata_test.c
secretmem.c
shmem.c mm: simplify try_to_unuse 2022-01-22 08:33:38 +02:00
shuffle.c
shuffle.h
slab.c
slab.h
slab_common.c
slob.c
slub.c
sparse-vmemmap.c
sparse.c
swap.c
swap_cgroup.c
swap_slots.c
swap_state.c
swapfile.c mm: mark swap_lock and swap_active_head static 2022-01-22 08:33:38 +02:00
truncate.c mm: remove cleancache 2022-01-22 08:33:38 +02:00
usercopy.c
userfaultfd.c
util.c
vmacache.c
vmalloc.c
vmpressure.c
vmscan.c
vmstat.c
workingset.c
z3fold.c
zbud.c
zpool.c
zsmalloc.c zsmalloc: replace get_cpu_var with local_lock 2022-01-22 08:33:37 +02:00
zswap.c frontswap: remove support for multiple ops 2022-01-22 08:33:38 +02:00