Commit 81bae4ed authored Oct 10, 2022 by Patrick Daly Committed by Gerrit - the friendly Code Review server Mar 27, 2023

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



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>
Git-commit: 1d05213028b6dbdb8801e20f29b6a6f91c216033
Git-repo: https://android.googlesource.com/kernel/common/


Signed-off-by: Srinivasarao Pathipati <quic_c_spathi@quicinc.com>

parent f350c4c6

mm/filemap.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -2662,11 +2662,14 @@ vm_fault_t filemap_fault(struct vm_fault *vmf)

		if (vmf->flags & FAULT_FLAG_SPECULATIVE) {
		page = find_get_page(mapping, offset);
		if (unlikely(!page) \|\| unlikely(PageReadahead(page)))
		if (unlikely(!page))
		return VM_FAULT_RETRY;

		if (unlikely(PageReadahead(page)))
		goto page_put;

		if (!trylock_page(page))
		return VM_FAULT_RETRY;
		goto page_put;

		if (unlikely(compound_head(page)->mapping != mapping))
		goto page_unlock;
		@@ -2698,6 +2701,8 @@ vm_fault_t filemap_fault(struct vm_fault *vmf)
		return VM_FAULT_LOCKED;
		page_unlock:
		unlock_page(page);
		page_put:
		put_page(page);
		return VM_FAULT_RETRY;
		}