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Message-ID: <87r14kzdqz.fsf@kernel.org>
Date: Mon, 23 May 2022 14:31:48 +0300
From: Kalle Valo <kvalo@...nel.org>
To: duoming@....edu.cn
Cc: "Greg KH" <gregkh@...uxfoundation.org>,
linux-wireless@...r.kernel.org, amitkarwar@...il.com,
ganapathi017@...il.com, sharvari.harisangam@....com,
huxinming820@...il.com, davem@...emloft.net, edumazet@...gle.com,
kuba@...nel.org, pabeni@...hat.com, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org, rafael@...nel.org,
Johannes Berg <johannes@...solutions.net>
Subject: Re: [PATCH v3] mwifiex: fix sleep in atomic context bugs caused by dev_coredumpv
(adding Johannes)
duoming@....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. Is there any
other option? What about adding a gfp_t parameter to dev_set_name()? Or
is there an alternative for dev_set_name() which can be called in atomic
contexts?
Johannes&Greg, any ideas?
--
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