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authorSoeren Sandmann <sandmann@daimi.au.dk>2009-10-28 13:55:36 -0400
committerIngo Molnar <mingo@elte.hu>2009-11-09 22:15:32 -0500
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')
-rw-r--r--mm/highmem.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/highmem.c b/mm/highmem.c
index 25878cc49daa..33587de6b871 100644
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -426,9 +426,9 @@ void __init page_address_init(void)
426 426
427void debug_kmap_atomic(enum km_type type) 427void debug_kmap_atomic(enum km_type type)
428{ 428{
429 static unsigned warn_count = 10; 429 static int warn_count = 10;
430 430
431 if (unlikely(warn_count == 0)) 431 if (unlikely(warn_count < 0))
432 return; 432 return;
433 433
434 if (unlikely(in_interrupt())) { 434 if (unlikely(in_interrupt())) {