2022-06-07 01:23:14

by Duoming Zhou

[permalink] [raw]
Subject: Re: [PATCH v5 2/2] mwifiex: fix sleep in atomic context bugs caused by dev_coredumpv

Hello,

On Mon, 6 Jun 2022 11:14:05 -0700 Brian wrote:

> On Fri, Jun 03, 2022 at 01:09:35PM +0800, Duoming Zhou wrote:
> > There are sleep in atomic context bugs when uploading device dump
> > data in mwifiex. The root cause is that dev_coredumpv could not
> > be used in atomic contexts, because it calls dev_set_name which
> > include operations that may sleep. The call tree shows execution
> > paths that could lead to bugs:
> ...
> > Fixes: f5ecd02a8b20 ("mwifiex: device dump support for usb interface")
> > Signed-off-by: Duoming Zhou <[email protected]>
> > ---
> > Changes in v5:
> > - Use delayed work to replace timer.
> >
> > drivers/net/wireless/marvell/mwifiex/init.c | 10 ++++++----
> > drivers/net/wireless/marvell/mwifiex/main.h | 2 +-
> > drivers/net/wireless/marvell/mwifiex/sta_event.c | 6 +++---
> > 3 files changed, 10 insertions(+), 8 deletions(-)
>
> Looks great! Thanks for working on this.
>
> Reviewed-by: Brian Norris <[email protected]>
>
> Some small nitpicks below, but they're definitely not critical.

Thank you for your time and approval!

> > diff --git a/drivers/net/wireless/marvell/mwifiex/init.c b/drivers/net/wireless/marvell/mwifiex/init.c
> > index 88c72d1827a..3713f3e323f 100644
> > --- a/drivers/net/wireless/marvell/mwifiex/init.c
> > +++ b/drivers/net/wireless/marvell/mwifiex/init.c
> > @@ -63,9 +63,11 @@ static void wakeup_timer_fn(struct timer_list *t)
> > adapter->if_ops.card_reset(adapter);
> > }
> >
> > -static void fw_dump_timer_fn(struct timer_list *t)
> > +static void fw_dump_work(struct work_struct *work)
> > {
> > - struct mwifiex_adapter *adapter = from_timer(adapter, t, devdump_timer);
> > + struct mwifiex_adapter *adapter = container_of(work,
> > + struct mwifiex_adapter,
> > + devdump_work.work);
>
> Super nitpicky: the hanging indent style seems a bit off. I typically
> see people try to align to the first character after the parenthesis,
> like:
>
> struct mwifiex_adapter *adapter = container_of(work,
> struct mwifiex_adapter,
> devdump_work.work);
>
> It's not a clearly-specified style rule I think, so I definitely
> wouldn't insist.
>
> On the bright side: I think the clang-format rules (in .clang-format)
> are getting better, so one can make some formatting decisions via tools
> instead of opinion and close reading! Unfortunately, we probably can't
> do that extensively and automatically, because I doubt people will love
> all the reformatting because of all the existing inconsistent style.
>
> Anyway, to cut to the chase: clang-format chooses moving to a new line:
>
> struct mwifiex_adapter *adapter =
> container_of(work, struct mwifiex_adapter, devdump_work.work);
>
> More info if you're interested:
> https://www.kernel.org/doc/html/latest/process/clang-format.html
>
> >
> > mwifiex_upload_device_dump(adapter);
> > }

Thanks for your suggestions! I will use clang-format to adjust the format.

> > diff --git a/drivers/net/wireless/marvell/mwifiex/main.h b/drivers/net/wireless/marvell/mwifiex/main.h
> > index 332dd1c8db3..6530c6ee308 100644
> > --- a/drivers/net/wireless/marvell/mwifiex/main.h
> > +++ b/drivers/net/wireless/marvell/mwifiex/main.h
> > @@ -1055,7 +1055,7 @@ struct mwifiex_adapter {
>
> Nitpick: main.h is probably missing a lot of #includes, but you could
> probably add <linux/workqueue.h> while you're at it.

I will add <linux/workqueue.h> in main.h.

>
> > /* Device dump data/length */
> > void *devdump_data;
> > int devdump_len;
> > - struct timer_list devdump_timer;
> > + struct delayed_work devdump_work;
> >
> > bool ignore_btcoex_events;
> > };

Best regards,
Duoming Zhou