Messages in this thread | | | From | Kalle Valo <> | Subject | Re: [PATCH v3 1/1] bus: mhi: host: Fix up null pointer access in mhi_irq_handler | Date | Tue, 26 Jul 2022 20:53:58 +0300 |
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Manivannan Sadhasivam <mani@kernel.org> writes:
> +ath11k, Kalle > > On Fri, Jul 22, 2022 at 11:17:18AM +0800, Qiang Yu wrote: >> The irq handler for a shared IRQ ought to be prepared for running >> even now it's being freed. So let's check the pointer used by >> mhi_irq_handler to avoid null pointer access since it is probably >> released before freeing IRQ. >> >> Signed-off-by: Qiang Yu <quic_qianyu@quicinc.com> > > Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
This fixes the crash and my regression tests pass now, thanks. But please see my question below.
Tested-by: Kalle Valo <kvalo@kernel.org>
>> + /* >> + * If CONFIG_DEBUG_SHIRQ is set, the IRQ handler will get invoked during __free_irq() >> + * and by that time mhi_ctxt() would've freed. So check for the existence of mhi_ctxt >> + * before handling the IRQs. >> + */ >> + if (!mhi_cntrl->mhi_ctxt) { >> + dev_dbg(&mhi_cntrl->mhi_dev->dev, >> + "mhi_ctxt has been freed\n"); >> + return IRQ_HANDLED; >> + }
I don't see any protection accessing mhi_cntrl->mhi_ctxt, is this really free of race conditions?
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