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authorLiam Howlett <liam.howlett@oracle.com>2022-10-11 16:08:37 +0000
committerAndrew Morton <akpm@linux-foundation.org>2022-10-12 15:56:46 -0700
commit28c5609fb236807910ca347ad3e26c4567998526 (patch)
tree8265bb663ef3fdc17e55234275bda4cc30b3b170 /mm/mmap.c
parent7be1c1a3c7b13fb259bb5159662a7b83622013b8 (diff)
mm/mmap: preallocate maple nodes for brk vma expansion
If the brk VMA is the last vma in a maple node and meets the rare criteria that it can be expanded, then preallocation is necessary to avoid a potential fs_reclaim circular lock issue on low resources. At the same time use the actual vma start address (unaligned) when calling vma_adjust_trans_huge(). Link: https://lkml.kernel.org/r/20221011160624.1253454-1-Liam.Howlett@oracle.com Fixes: 2e7ce7d354f2 (mm/mmap: change do_brk_flags() to expand existing VMA and add do_brk_munmap()) Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reported-by: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/mmap.c')
-rw-r--r--mm/mmap.c18
1 files changed, 6 insertions, 12 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index fc8581cefef7..5855f26639f9 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2942,17 +2942,18 @@ static int do_brk_flags(struct ma_state *mas, struct vm_area_struct *vma,
if (vma &&
(!vma->anon_vma || list_is_singular(&vma->anon_vma_chain)) &&
((vma->vm_flags & ~VM_SOFTDIRTY) == flags)) {
- mas->index = vma->vm_start;
- mas->last = addr + len - 1;
- vma_adjust_trans_huge(vma, addr, addr + len, 0);
+ mas_set_range(mas, vma->vm_start, addr + len - 1);
+ if (mas_preallocate(mas, vma, GFP_KERNEL))
+ return -ENOMEM;
+
+ vma_adjust_trans_huge(vma, vma->vm_start, addr + len, 0);
if (vma->anon_vma) {
anon_vma_lock_write(vma->anon_vma);
anon_vma_interval_tree_pre_update_vma(vma);
}
vma->vm_end = addr + len;
vma->vm_flags |= VM_SOFTDIRTY;
- if (mas_store_gfp(mas, vma, GFP_KERNEL))
- goto mas_expand_failed;
+ mas_store_prealloc(mas, vma);
if (vma->anon_vma) {
anon_vma_interval_tree_post_update_vma(vma);
@@ -2993,13 +2994,6 @@ mas_store_fail:
vma_alloc_fail:
vm_unacct_memory(len >> PAGE_SHIFT);
return -ENOMEM;
-
-mas_expand_failed:
- if (vma->anon_vma) {
- anon_vma_interval_tree_post_update_vma(vma);
- anon_vma_unlock_write(vma->anon_vma);
- }
- return -ENOMEM;
}
int vm_brk_flags(unsigned long addr, unsigned long request, unsigned long flags)