diff options
| author | Liam Howlett <liam.howlett@oracle.com> | 2022-10-11 16:08:37 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2022-10-12 15:56:46 -0700 |
| commit | 28c5609fb236807910ca347ad3e26c4567998526 (patch) | |
| tree | 8265bb663ef3fdc17e55234275bda4cc30b3b170 /mm | |
| parent | 7be1c1a3c7b13fb259bb5159662a7b83622013b8 (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')
| -rw-r--r-- | mm/mmap.c | 18 |
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) |