Messages in this thread Patch in this message | | | From | Frederic Weisbecker <> | Subject | [PATCH] lockdep: Fix redundant_hardirqs_on incremented with irqs enabled | Date | Thu, 15 Apr 2010 15:37:50 +0200 |
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When a path restore the flags while irqs are already enabled, we update the per cpu var redundant_hardirqs_on in a racy fashion and debug_atomic_inc() warns about this situation.
In this particular case, we need to explictly disable the irqs before updating this stat var in order to update it safely.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: David Miller <davem@davemloft.net> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- kernel/lockdep.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 78325f8..65d4336 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -2298,7 +2298,11 @@ void trace_hardirqs_on_caller(unsigned long ip) return; if (unlikely(curr->hardirqs_enabled)) { + unsigned long flags; + + raw_local_irq_save(flags); debug_atomic_inc(redundant_hardirqs_on); + raw_local_irq_restore(flags); return; } /* we'll do an OFF -> ON transition: */ -- 1.6.2.3
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