linux-kernel - Re: [PATCH] timers: Provide a better debugobjects hint for delayed works

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Date:   Thu, 12 May 2022 00:57:57 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Stephen Boyd <swboyd@...omium.org>,
        John Stultz <john.stultz@...aro.org>
Cc:     linux-kernel@...r.kernel.org, patches@...ts.linux.dev,
        Tejun Heo <tj@...nel.org>,
        Lai Jiangshan <jiangshanlai@...il.com>,
        Guenter Roeck <groeck@...omium.org>
Subject: Re: [PATCH] timers: Provide a better debugobjects hint for delayed
 works

On Wed, May 11 2022 at 13:02, Stephen Boyd wrote:
> Quoting Thomas Gleixner (2022-05-10 02:20:01)
>>  static void *timer_debug_hint(void *addr)
>>  {
>> -       return ((struct timer_list *) addr)->function;
>> +       struct timer_list *timer = addr;
>> +       int i;
>> +
>> +       for (i = 0; i < ARRAY_SIZE(timer_hints); i++) {
>> +               if (timer_hints[i].function == timer->function)
>> +                       return addr + timer_hints[i].offset;
>
> This locates the correct address of the function pointer 'work.func' but
> it needs to be dereferenced to return the function's address instead of
> the pointer to the function. We don't really care about the function
> signature so we could cast it to a void function pointer and deref:
>
>                       void (**fn)(void) = addr + timer_hints[i].offset;

That's why I said: "So maybe something like the uncompiled/untested
below."

I was pretty sure that I missed some nasty detail.

> I'll send this version of the patch.

Appreciated.

Thanks,

        tglx