linux-kernel - Re: [PATCH] treewide: Convert del_timer*() to timer

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Date:   Wed, 21 Dec 2022 20:47:50 +0200
From:   Kalle Valo <kvalo@...nel.org>
To:     Steven Rostedt <rostedt@...dmis.org>
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        LKML <linux-kernel@...r.kernel.org>,
        Stephen Boyd <sboyd@...nel.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Anna-Maria Gleixner <anna-maria@...utronix.de>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Julia Lawall <Julia.Lawall@...ia.fr>, linux-sh@...r.kernel.org,
        cgroups@...r.kernel.org, linux-block@...r.kernel.org,
        linux-acpi@...r.kernel.org,
        linux-atm-general@...ts.sourceforge.net, netdev@...r.kernel.org,
        drbd-dev@...ts.linbit.com, linux-bluetooth@...r.kernel.org,
        intel-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-input@...r.kernel.org, linux-leds@...r.kernel.org,
        linux-media@...r.kernel.org, intel-wired-lan@...ts.osuosl.org,
        linux-usb@...r.kernel.org, linux-wireless@...r.kernel.org,
        brcm80211-dev-list.pdl@...adcom.com,
        SHA-cyfmac-dev-list@...ineon.com, linux-scsi@...r.kernel.org,
        linux-staging@...ts.linux.dev, linux-ext4@...r.kernel.org,
        linux-nilfs@...r.kernel.org, bridge@...ts.linux-foundation.org,
        netfilter-devel@...r.kernel.org, coreteam@...filter.org,
        lvs-devel@...r.kernel.org, linux-nfs@...r.kernel.org,
        tipc-discussion@...ts.sourceforge.net, alsa-devel@...a-project.org
Subject: Re: [PATCH] treewide: Convert del_timer*() to timer_shutdown*()

Steven Rostedt <rostedt@...dmis.org> writes:

> [
>   Linus,
>
>     I ran the script against your latest master branch:
>     commit b6bb9676f2165d518b35ba3bea5f1fcfc0d969bf
>
>     As the timer_shutdown*() code is now in your tree, I figured
>     we can start doing the conversions. At least add the trivial ones
>     now as Thomas suggested that this gets applied at the end of the
>     merge window, to avoid conflicts with linux-next during the
>     development cycle. I can wait to Friday to run it again, and
>     resubmit.
>
>     What is the best way to handle this?
> ]
>
> From: "Steven Rostedt (Google)" <rostedt@...dmis.org>
>
> Due to several bugs caused by timers being re-armed after they are
> shutdown and just before they are freed, a new state of timers was added
> called "shutdown". After a timer is set to this state, then it can no
> longer be re-armed.
>
> The following script was run to find all the trivial locations where
> del_timer() or del_timer_sync() is called in the same function that the
> object holding the timer is freed. It also ignores any locations where the
> timer->function is modified between the del_timer*() and the free(), as
> that is not considered a "trivial" case.
>
> This was created by using a coccinelle script and the following commands:
>
>  $ cat timer.cocci
> @@
> expression ptr, slab;
> identifier timer, rfield;
> @@
> (
> -       del_timer(&ptr->timer);
> +       timer_shutdown(&ptr->timer);
> |
> -       del_timer_sync(&ptr->timer);
> +       timer_shutdown_sync(&ptr->timer);
> )
>   ... when strict
>       when != ptr->timer
> (
>         kfree_rcu(ptr, rfield);
> |
>         kmem_cache_free(slab, ptr);
> |
>         kfree(ptr);
> )
>
>  $ spatch timer.cocci . > /tmp/t.patch
>  $ patch -p1 < /tmp/t.patch
>
> Link: https://lore.kernel.org/lkml/20221123201306.823305113@linutronix.de/
>
> Signed-off-by: Steven Rostedt (Google) <rostedt@...dmis.org>

For wireless:

>  .../broadcom/brcm80211/brcmfmac/btcoex.c         |  2 +-
>  drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c |  2 +-
>  drivers/net/wireless/intel/iwlwifi/mvm/sta.c     |  2 +-
>  drivers/net/wireless/intersil/hostap/hostap_ap.c |  2 +-
>  drivers/net/wireless/marvell/mwifiex/main.c      |  2 +-
>  drivers/net/wireless/microchip/wilc1000/hif.c    |  6 +++---

Acked-by: Kalle Valo <kvalo@...nel.org>

-- 
https://patchwork.kernel.org/project/linux-wireless/list/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches