From f12d5bfceb7e1f9051563381ec047f7f13956c3c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Thu, 12 Dec 2013 09:38:42 -0800 Subject: [PATCH] futex: fix handling of read-only-mapped hugepages The hugepage code had the exact same bug that regular pages had in commit 7485d0d3758e ("futexes: Remove rw parameter from get_futex_key()"). The regular page case was fixed by commit 9ea71503a8ed ("futex: Fix regression with read only mappings"), but the transparent hugepage case (added in a5b338f2b0b1: "thp: update futex compound knowledge") case remained broken. Found by Dave Jones and his trinity tool. Reported-and-tested-by: Dave Jones Cc: stable@kernel.org # v2.6.38+ Acked-by: Thomas Gleixner Cc: Mel Gorman Cc: Darren Hart Cc: Andrea Arcangeli Cc: Oleg Nesterov Signed-off-by: Linus Torvalds --- kernel/futex.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/futex.c b/kernel/futex.c index 80ba086f021d..02febad00794 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -288,7 +288,7 @@ again: put_page(page); /* serialize against __split_huge_page_splitting() */ local_irq_disable(); - if (likely(__get_user_pages_fast(address, 1, 1, &page) == 1)) { + if (likely(__get_user_pages_fast(address, 1, !ro, &page) == 1)) { page_head = compound_head(page); /* * page_head is valid pointer but we must pin