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| author | Laura Abbott <labbott@fedoraproject.org> | 2016-08-10 13:00:33 -0700 |
|---|---|---|
| committer | Laura Abbott <labbott@fedoraproject.org> | 2016-08-10 13:00:33 -0700 |
| commit | 2acb794259760b4aca1b0aa26afaa61170167546 (patch) | |
| tree | 7eea9cba6b5ac9e10a9e7a79bca00b97df231a59 | |
| parent | 23689dd81c4eb7dbf43c9a070ae4c04182ce368d (diff) | |
| download | kernel-2acb794259760b4aca1b0aa26afaa61170167546.tar.gz kernel-2acb794259760b4aca1b0aa26afaa61170167546.tar.xz kernel-2acb794259760b4aca1b0aa26afaa61170167546.zip | |
Fix false positive VM_BUG() in page_add_file_rmap (rhbz 1365686)
| -rw-r--r-- | 0001-mm-rmap-fix-false-positive-VM_BUG-in-page_add_file_r.patch | 44 | ||||
| -rw-r--r-- | kernel.spec | 6 |
2 files changed, 50 insertions, 0 deletions
diff --git a/0001-mm-rmap-fix-false-positive-VM_BUG-in-page_add_file_r.patch b/0001-mm-rmap-fix-false-positive-VM_BUG-in-page_add_file_r.patch new file mode 100644 index 000000000..276e2be32 --- /dev/null +++ b/0001-mm-rmap-fix-false-positive-VM_BUG-in-page_add_file_r.patch @@ -0,0 +1,44 @@ +From 6abb0cfdc1f6a42367a20ac2baf4099fc8af08b5 Mon Sep 17 00:00:00 2001 +From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> +Date: Wed, 10 Aug 2016 09:54:30 -0700 +Subject: [PATCH] mm, rmap: fix false positive VM_BUG() in page_add_file_rmap() + +PageTransCompound() doesn't distinguish THP from from any other type of +compound pages. This can lead to false-positive VM_BUG_ON() in +page_add_file_rmap() if called on compound page from a driver[1]. + +I think we can exclude such cases by checking if the page belong to a +mapping. + +The VM_BUG_ON_PAGE() is downgraded to VM_WARN_ON_ONCE(). This path +should not cause any harm to non-THP page, but good to know if we step +on anything else. + +[1] +http://lkml.kernel.org/r/c711e067-0bff-a6cb-3c37-04dfe77d2db1@redhat.com + +Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> +Reported-by: Laura Abbott <labbott@redhat.com> +--- + mm/rmap.c | 5 +++-- + 1 file changed, 3 insertions(+), 2 deletions(-) + +diff --git a/mm/rmap.c b/mm/rmap.c +index 709bc83..d4f5606 100644 +--- a/mm/rmap.c ++++ b/mm/rmap.c +@@ -1284,8 +1284,9 @@ void page_add_file_rmap(struct page *page, bool compound) + VM_BUG_ON_PAGE(!PageSwapBacked(page), page); + __inc_node_page_state(page, NR_SHMEM_PMDMAPPED); + } else { +- if (PageTransCompound(page)) { +- VM_BUG_ON_PAGE(!PageLocked(page), page); ++ if (PageTransCompound(page) && page_mapping(page)) { ++ VM_WARN_ON_ONCE(!PageLocked(page)); ++ + SetPageDoubleMap(compound_head(page)); + if (PageMlocked(page)) + clear_page_mlock(compound_head(page)); +-- +2.7.4 + diff --git a/kernel.spec b/kernel.spec index c7aa19fbd..e0f5d20fd 100644 --- a/kernel.spec +++ b/kernel.spec @@ -601,6 +601,9 @@ Patch665: netfilter-x_tables-deal-with-bogus-nextoffset-values.patch # https://lists.fedoraproject.org/archives/list/kernel@lists.fedoraproject.org/message/A4YCP7OGMX6JLFT5V44H57GOMAQLC3M4/ Patch839: drm-i915-Acquire-audio-powerwell-for-HD-Audio-regist.patch +#rhbz 1365686 +Patch840: 0001-mm-rmap-fix-false-positive-VM_BUG-in-page_add_file_r.patch + # END OF PATCH DEFINITIONS %endif @@ -2135,6 +2138,9 @@ fi # # %changelog +* Wed Aug 10 2016 Laura Abbott <labbott@fedoraproject.org> +- Fix false positive VM_BUG() in page_add_file_rmap (rhbz 1365686) + * Wed Aug 10 2016 Justin M. Forbes <jforbes@fedoraproject.org> - 4.8.0-0.rc1.git2.1 - Linux v4.8-rc1-53-ga0cba21 |