From: Kalle Valo <kvalo@kernel.org>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: duoming@zju.edu.cn, linux-wireless@vger.kernel.org,
amitkarwar@gmail.com, ganapathi017@gmail.com,
sharvari.harisangam@nxp.com, huxinming820@gmail.com,
davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
pabeni@redhat.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, rafael@kernel.org,
Johannes Berg <johannes@sipsolutions.net>
Subject: Re: [PATCH v3] mwifiex: fix sleep in atomic context bugs caused by dev_coredumpv
Date: Mon, 23 May 2022 19:27:00 +0300 [thread overview]
Message-ID: <87ilpwz02z.fsf@kernel.org> (raw)
In-Reply-To: <YouPEdlNbU2ea1Cx@kroah.com> (Greg KH's message of "Mon, 23 May 2022 15:41:37 +0200")
Greg KH <gregkh@linuxfoundation.org> writes:
> On Mon, May 23, 2022 at 02:31:48PM +0300, Kalle Valo wrote:
>> (adding Johannes)
>>
>> duoming@zju.edu.cn writes:
>>
>> >> > --- a/lib/kobject.c
>> >> > +++ b/lib/kobject.c
>> >> > @@ -254,7 +254,7 @@ int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
>> >> > if (kobj->name && !fmt)
>> >> > return 0;
>> >> >
>> >> > - s = kvasprintf_const(GFP_KERNEL, fmt, vargs);
>> >> > + s = kvasprintf_const(GFP_ATOMIC, fmt, vargs);
>> >> > if (!s)
>> >> > return -ENOMEM;
>> >> >
>> >> > @@ -267,7 +267,7 @@ int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
>> >> > if (strchr(s, '/')) {
>> >> > char *t;
>> >> >
>> >> > - t = kstrdup(s, GFP_KERNEL);
>> >> > + t = kstrdup(s, GFP_ATOMIC);
>> >> > kfree_const(s);
>> >> > if (!t)
>> >> > return -ENOMEM;
>> >>
>> >> Please no, you are hurting the whole kernel because of one odd user.
>> >> Please do not make these calls under atomic context.
>> >
>> > Thanks for your time and suggestions. I will remove the gfp_t
>> > parameter of dev_coredumpv in order to show it could not be used in
>> > atomic context.
>>
>> In a way it would be nice to be able to call dev_coredump from atomic
>> contexts, though I don't know how practical it actually is.
>
> Dumping core information from atomic context feels very very wrong to
> me.
>
> Why not just not do that?
I was wondering why dev_coredumpm() has the gfp parameter in the first
place. But yeah, removing gfp from devcoredump API altogether sounds
like the best thing to do.
--
https://patchwork.kernel.org/project/linux-wireless/list/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
next prev parent reply other threads:[~2022-05-23 16:27 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-23 5:28 [PATCH v3] mwifiex: fix sleep in atomic context bugs caused by dev_coredumpv Duoming Zhou
2022-05-23 6:31 ` Greg KH
[not found] ` <41a266af.2abb6.180efa8594d.Coremail.duoming@zju.edu.cn>
2022-05-23 11:31 ` Kalle Valo
2022-05-23 13:41 ` Greg KH
2022-05-23 16:27 ` Kalle Valo [this message]
2022-05-23 13:43 ` Johannes Berg
2022-05-23 14:20 ` Eric W. Biederman
2022-05-23 15:58 ` duoming
2022-05-23 16:31 ` Kalle Valo
2022-05-24 2:08 ` duoming
2022-05-23 19:42 ` Brian Norris
2022-05-24 1:54 ` duoming
2022-05-23 17:55 ` Brian Norris
2022-05-23 8:03 duoming
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