Eric Lee / linux-smarc-t335x-v3.2

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Commit a95a82e96c48270980dd248ccd5546f1b49e6f8a

Authored by Andrea Arcangeli
Committed by Linus Torvalds
1 parent 9180706344
Exists in master and in 4 other branches v3.2_AM335xPSP_04.06.00.11, v3.2_NEWT335xPSP_04.06.00.11, v3.2_SBC_SMARTMEN, v3.2_SMARCT335xPSP_04.06.00.11

thp: put_page: recheck PageHead after releasing the compound_lock 

After releasing the compound_lock split_huge_page can still run and release the
page before put_page_testzero runs.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Showing 1 changed file with 6 additions and 2 deletions Side-by-side Diff

... ... @@ -131,8 +131,12 @@
131 131 atomic_dec(&page->_count);
132 132 VM_BUG_ON(atomic_read(&page_head->_count) <= 0);
133 133 compound_unlock_irqrestore(page_head, flags);
134   - if (put_page_testzero(page_head))
135   - __put_compound_page(page_head);
  134 + if (put_page_testzero(page_head)) {
  135 + if (PageHead(page_head))
  136 + __put_compound_page(page_head);
  137 + else
  138 + __put_single_page(page_head);
  139 + }
136 140 } else {
137 141 /* page_head is a dangling pointer */
138 142 VM_BUG_ON(PageTail(page));