diff options
| author | Soeren Sandmann <sandmann@daimi.au.dk> | 2009-10-28 18:55:36 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-11-10 04:15:32 +0100 |
| commit | 5ebd4c22897dce65845807a9bd3a31cc4e142b53 (patch) | |
| tree | d56865116e9961450c48c46ae3d346956f66b180 /mm/highmem.c | |
| parent | 83f5b01ffbbaea6f97c9a79d21e240dbfb69f2f1 (diff) | |
| download | lwn-5ebd4c22897dce65845807a9bd3a31cc4e142b53.tar.gz lwn-5ebd4c22897dce65845807a9bd3a31cc4e142b53.zip | |
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.c | 4 |
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) 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)) return; if (unlikely(in_interrupt())) { |