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ANDROID: mm/filemap: Fix missing put_page() for speculative page fault

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find_get_page() returns a page with increased refcount, assuming a page
exists at the given index. Ensure this refcount is dropped on error.

Bug: 271079833
Fixes: 59d4d125 ("BACKPORT: FROMLIST: mm: implement speculative handling in filemap_fault()")
Change-Id: Idc7b9e3f11f32a02bed4c6f4e11cec9200a5c790
Signed-off-by: Patrick Daly <quic_pdaly@quicinc.com>
(cherry picked from commit 6232eecfa7ca0d8d0ca088da6d0edb2c3a879ff9)
Signed-off-by: Zhenhua Huang <quic_zhenhuah@quicinc.com>
This commit is contained in:
Patrick Daly
2022-10-10 19:25:27 -07:00
committed by Suren Baghdasaryan
parent fda8a58faa
commit 1d05213028
1 changed files with 7 additions and 2 deletions
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9
mm/filemap.c
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@@ -2736,11 +2736,14 @@ vm_fault_t filemap_fault(struct vm_fault *vmf)
if (vmf->flags & FAULT_FLAG_SPECULATIVE) { if (vmf->flags & FAULT_FLAG_SPECULATIVE) {
page = find_get_page(mapping, offset); page = find_get_page(mapping, offset);
if (unlikely(!page) || unlikely(PageReadahead(page))) if (unlikely(!page))
return VM_FAULT_RETRY; return VM_FAULT_RETRY;
if (unlikely(PageReadahead(page)))
goto page_put;
if (!trylock_page(page)) if (!trylock_page(page))
return VM_FAULT_RETRY; goto page_put;
if (unlikely(compound_head(page)->mapping != mapping)) if (unlikely(compound_head(page)->mapping != mapping))
goto page_unlock; goto page_unlock;
@@ -2772,6 +2775,8 @@ vm_fault_t filemap_fault(struct vm_fault *vmf)
return VM_FAULT_LOCKED; return VM_FAULT_LOCKED;
page_unlock: page_unlock:
unlock_page(page); unlock_page(page);
page_put:
put_page(page);
return VM_FAULT_RETRY; return VM_FAULT_RETRY;
} }