path: root/mm/highmem.c
diff options
authorSoeren Sandmann <sandmann@daimi.au.dk>2009-10-28 18:55:36 +0100
committerIngo Molnar <mingo@elte.hu>2009-11-10 04:15:32 +0100
commit5ebd4c22897dce65845807a9bd3a31cc4e142b53 (patch)
treed56865116e9961450c48c46ae3d346956f66b180 /mm/highmem.c
parent83f5b01ffbbaea6f97c9a79d21e240dbfb69f2f1 (diff)
highmem: Fix race in debug_kmap_atomic() which could cause warn_count to underflow
debug_kmap_atomic() tries to prevent ever printing more than 10 warnings, but it does so by testing whether an unsigned integer is equal to 0. However, if the warning is caused by a nested IRQ, then this counter may underflow and the stream of warnings will never end. Fix that by using a signed integer instead. Signed-off-by: Soeren Sandmann Pedersen <sandmann@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: a.p.zijlstra@chello.nl Cc: <stable@kernel.org> # .31.x LKML-Reference: <ye8zl7b8ktj.fsf@camel23.daimi.au.dk> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'mm/highmem.c')
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/highmem.c b/mm/highmem.c
index 25878cc49da..33587de6b87 100644
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -426,9 +426,9 @@ void __init page_address_init(void)
void debug_kmap_atomic(enum km_type type)
- static unsigned warn_count = 10;
+ static int warn_count = 10;
- if (unlikely(warn_count == 0))
+ if (unlikely(warn_count < 0))
if (unlikely(in_interrupt())) {