Commit f12d5bfc authored Dec 12, 2013 by Linus Torvalds

futex: fix handling of read-only-mapped hugepages



The hugepage code had the exact same bug that regular pages had in
commit 7485d0d3 ("futexes: Remove rw parameter from
get_futex_key()").

The regular page case was fixed by commit 9ea71503 ("futex: Fix
regression with read only mappings"), but the transparent hugepage case
(added in a5b338f2: "thp: update futex compound knowledge") case
remained broken.

Found by Dave Jones and his trinity tool.

Reported-and-tested-by: Dave Jones <davej@fedoraproject.org>
Cc: stable@kernel.org # v2.6.38+
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Darren Hart <dvhart@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 9538e100

kernel/futex.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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

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