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Date:   Fri, 27 Mar 2020 22:55:14 -0400 (EDT)
From:   Nicolas Pitre <nico@fluxnic.net>
To:     Chen Wandun <chenwandun@huawei.com>
cc:     jslaby@suse.com, gregkh@linuxfoundation.org,
        daniel.vetter@ffwll.ch, sam@ravnborg.org, b.zolnierkie@samsung.com,
        lukas@wunner.de, ghalat@redhat.com, kilobyte@angband.pl,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH next] vt: fix a warning when kmalloc alloc large memory
In-Reply-To: <20200328021340.27315-1-chenwandun@huawei.com>
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On Sat, 28 Mar 2020, Chen Wandun wrote:

> If the memory size that use kmalloc() to allocate exceed MAX_ORDER pages,
> it will hit the WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN)), so add memory
> allocation flag __GFP_NOWARN to silence a warning, othervise, it will
> cause panic if panic_on_warn is enable.

Wow! How do you manage that? You need something like a 1024x1024 text 
screen to get such a big memory allocation.

Still, GFP_NOWARN is not a proper fix. This kmalloc() should rather be 
replaced by vmalloc(), and corresponding kfree() should then be vfree(). 
There is no need for this allocation to be physically contiguous.


Nicolas