linux-kernel - Re: [PATCH 34/40] lib: code tagging context capture support

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Message-ID: <b8ab89e6-0456-969d-ed31-fa64be0a0fd0@intel.com>
Date:   Wed, 3 May 2023 08:26:40 -0700
From:   Dave Hansen <dave.hansen@...el.com>
To:     Suren Baghdasaryan <surenb@...gle.com>,
        Michal Hocko <mhocko@...e.com>
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Subject: Re: [PATCH 34/40] lib: code tagging context capture support

On 5/3/23 08:18, Suren Baghdasaryan wrote:
>>> +static inline void rem_ctx(struct codetag_ctx *ctx,
>>> +                        void (*free_ctx)(struct kref *refcount))
>>> +{
>>> +     struct codetag_with_ctx *ctc = ctx->ctc;
>>> +
>>> +     spin_lock(&ctc->ctx_lock);
>> This could deadlock when allocator is called from the IRQ context.
> I see. spin_lock_irqsave() then?

Yes.  But, even better, please turn on lockdep when you are testing.  It
will find these for you.  If you're on x86, we have a set of handy-dandy
debug options that you can add to an existing config with:

	make x86_debug.config

That said, I'm as concerned as everyone else that this is all "new" code
and doesn't lean on existing tracing or things like PAGE_OWNER enough.