Re: [PATCH] futex: add WARN_ON to catch certain assymetric(get|put)_futex_key calls

From: Ingo Molnar
Date: Tue Dec 30 2008 - 00:43:28 EST



* Darren Hart <dvhltc@xxxxxxxxxx> wrote:

> Following up on my previous key reference accounting patches, this patch
> will catch puts on keys that haven't been "got". This won't catch nested
> get/put mismatches though.
>
> Build and boot tested, with minimal desktop activity and a run of the
> open_posix_testsuite in LTP for testing. No warnings logged.
>
> Signed-off-by: Darren Hart <dvhltc@xxxxxxxxxx>
> Cc: "Peter Zijlstra" <peterz@xxxxxxxxxxxxx>
> Cc: "Thomas Gleixner" <tglx@xxxxxxxxxxxxx>
> Cc: "Rusty Russell" <rusty@xxxxxxxxxxx>
> ---
>
> kernel/futex.c | 5 ++++-
> 1 files changed, 4 insertions(+), 1 deletions(-)

applied to tip/core/futexes, thanks!

I changed this:

> + WARN_ON(1);
> return;

to WARN_ON_ONCE() - warning once per bootup is good enough for
kerneloops.org to pick it up, while a ton of warnings add no extra (other
than to inconvenience the user, or even make the system unworkable).

Ingo
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