Re: [PATCH] treewide: Convert del_timer*() to timer_shutdown*()

Kalle Valo
2022-12-21T18:48:07Z

Steven Rostedt <rostedt@goodmis.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@goodmis.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@goodmis.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@kernel.org>

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