From: Doug Anderson <dianders@chromium.org>
To: Stephen Boyd <swboyd@chromium.org>
Cc: Konrad Dybcio <konrad.dybcio@linaro.org>,
Bjorn Andersson <andersson@kernel.org>,
linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
patches@lists.linux.dev,
Dan Carpenter <dan.carpenter@linaro.org>
Subject: Re: [PATCH] soc: qcom: rpmh-rsc: Ensure irqs aren't disabled by rpmh_rsc_send_data() callers
Date: Thu, 9 May 2024 12:34:59 -0700 [thread overview]
Message-ID: <CAD=FV=VP+DDQbdb-pD2JJKrZ+MrkgcuyzBj4H-4oTDVvBpTOtQ@mail.gmail.com> (raw)
In-Reply-To: <20240509184129.3924422-1-swboyd@chromium.org>
Hi,
On Thu, May 9, 2024 at 11:41 AM Stephen Boyd <swboyd@chromium.org> wrote:
>
> Dan pointed out that Smatch is concerned about this code because it uses
> spin_lock_irqsave() and then calls wait_event_lock_irq() which enables
> irqs before going to sleep. The comment above the function says it
> should be called with interrupts enabled, but we simply hope that's true
> without really confirming that. Let's add a might_sleep() here to
> confirm that interrupts and preemption aren't disabled. Once we do that,
> we can change the lock to be non-saving, spin_lock_irq(), to clarify
> that we don't expect irqs to be disabled. If irqs are disabled by
> callers they're going to be enabled anyway in the wait_event_lock_irq()
> call which would be bad.
>
> This should make Smatch happier and find bad callers faster with the
> might_sleep(). We can drop the WARN_ON() in the caller because we have
> the might_sleep() now, simplifying the code.
>
> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> Closes: https://lore.kernel.org/r/911181ed-c430-4592-ad26-4dc948834e08@moroto.mountain
> Fixes: 2bc20f3c8487 ("soc: qcom: rpmh-rsc: Sleep waiting for tcs slots to be free")
> Cc: Douglas Anderson <dianders@chromium.org>
> Signed-off-by: Stephen Boyd <swboyd@chromium.org>
> ---
> drivers/soc/qcom/rpmh-rsc.c | 7 ++++---
> drivers/soc/qcom/rpmh.c | 1 -
> 2 files changed, 4 insertions(+), 4 deletions(-)
Reviewed-by: Douglas Anderson <dianders@chromium.org>
next prev parent reply other threads:[~2024-05-09 19:35 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-09 18:41 [PATCH] soc: qcom: rpmh-rsc: Ensure irqs aren't disabled by rpmh_rsc_send_data() callers Stephen Boyd
2024-05-09 19:34 ` Doug Anderson [this message]
2024-05-28 3:32 ` Bjorn Andersson
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