Commit 95156f00 authored Jan 12, 2009 by Peter Zijlstra Committed by Ingo Molnar Jan 12, 2009

lockdep, mm: fix might_fault() annotation



Some code (nfs/sunrpc) uses socket ops on kernel memory while holding
the mmap_sem, this is safe because kernel memory doesn't get paged out,
therefore we'll never actually fault, and the might_fault() annotations
will generate false positives.

Reported-by: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 9d079337

mm/memory.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -3165,6 +3165,15 @@ void print_vma_addr(char *prefix, unsigned long ip)
		#ifdef CONFIG_PROVE_LOCKING
		void might_fault(void)
		{
		/*
		* Some code (nfs/sunrpc) uses socket ops on kernel memory while
		* holding the mmap_sem, this is safe because kernel memory doesn't
		* get paged out, therefore we'll never actually fault, and the
		* below annotations will generate false positives.
		*/
		if (segment_eq(get_fs(), KERNEL_DS))
		return;

		might_sleep();
		/*
		* it would be nicer only to annotate paths which are not under

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