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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2009-01-12 13:02:11 +0100
committerIngo Molnar <mingo@elte.hu>2009-01-12 13:09:18 +0100
commit95156f0051cba60ec674bbaa5cf7dc74a74c5612 (patch)
treeb2927d543b7b8e89e8dcb7ebf7f37d07afdc62f0 /mm
parent9d0793370987b98708d2f75ee3bba7c1008d8512 (diff)
downloadlinux-95156f0051cba60ec674bbaa5cf7dc74a74c5612.tar.gz
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>
Diffstat (limited to 'mm')
-rw-r--r--mm/memory.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/mm/memory.c b/mm/memory.c
index e009ce87085..c2d4c477e5b 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -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