linux-kernel - Re: [PATCH v4a 00/38] timers: Use timer

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Date:   Sat, 5 Nov 2022 23:12:41 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Julia Lawall <julia.lawall@...ia.fr>
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
        Stephen Boyd <sboyd@...nel.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Anna-Maria Gleixner <anna-maria@...utronix.de>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH v4a 00/38] timers: Use timer_shutdown*() before freeing
 timers

On Sun, 6 Nov 2022 11:05:14 +0800 (+08)
Julia Lawall <julia.lawall@...ia.fr> wrote:

> > Thinking that's what you meant (examples would be easier to understand,
> > than descriptions). And it didn't cover the return case. Does it only
> > cover gotos?
> >
> >   See drivers/net/wireless/intel/iwlwifi/mvm/sta.c for the false positive case:
> >
> > 	del_timer_sync(&baid_data->session_timer);
> > [..]  
> 
> But there is a kfree_rcu(baid_data, rcu_head); right below.  So it looks
> fine?

D'oh! I think you are correct. I didn't trust the script and it appears
that it was correct all along. The free was hidden in between the code
and I only noticed the kfree() in the error path. I thought that was a
bug in the script. :-/

I guess there were no false positives then. To be sure, I'll write a
script to find all that have a return or goto in between and see what
it comes up with.

I guess my original patch doesn't need any changes from the script.
I'll look more.

Thanks Julia!

-- Steve